Title of Invention	ALPHA-KETOAMIDE DERIVATIVE, AND PRODUCTION METHOD AND USE THEREOF
Abstract	The present invention provides a compound represented by the formula (I): (INSERT CHEMICAL FORMULA) (wherein R1 is a lower alkyl substituted by a lower alkoxy or a heterocyclic group, or a heterocyclic group; R2 is a lower alkyl optionally substituted by a phenyl; and R3 is a lower alkyl optionally substituted by a halogen, a lower alkoxy or a phenyl, or a fused polycyclic hydrocarbon group), which is well absorbed orally, exhibits durability of good blood level and has potent calpain inhibitory aclivity.

Title of Invention

ALPHA-KETOAMIDE DERIVATIVE, AND PRODUCTION METHOD AND USE THEREOF

Abstract

The present invention provides a compound represented by the formula (I): (INSERT CHEMICAL FORMULA) (wherein R1 is a lower alkyl substituted by a lower alkoxy or a heterocyclic group, or a heterocyclic group; R2 is a lower alkyl optionally substituted by a phenyl; and R3 is a lower alkyl optionally substituted by a halogen, a lower alkoxy or a phenyl, or a fused polycyclic hydrocarbon group), which is well absorbed orally, exhibits durability of good blood level and has potent calpain inhibitory aclivity.

Full Text	DESCRIPTION ALPHα-ketoamide DERIVATIVE, AND PRODUCTION METHOD AND USE THEREOF Technical Field The present invention relates to a novel α-ketoamide derivative having calpain inhibitory activity. Also, the present invention relates to a medicament comprising the novel 1379/KOLNP/2006 α-ketoamide derivative. Background Art Calpain is one of the intracellular proteases ubiquitously present in a living body, which is activated by Ca2+. It has been elucidated to this day that abnormal activation of calpain is involved in various diseases such as cerebral apoplexy, subarachnoid hemorrhage, Alzheimer's disease, ischemic disease, muscular dystrophy, cataract, platelet aggregation disorder, arthritis and the like (see Non-patent literature 1). On the other hand, it has been reported that a calpain inhibitor is effective for maintaining permeability of lens in an experimental cataract model of cultured lens and is useful as a therapeutic agent for cataract, etc. (see Non-patent literature 2, Patent literature 1). Examples of calpain inhibitors which have been so far reported are peptide halomethane derivatives, peptide diazomethane derivatives, peptidyl aldehyde derivatives, peptidyl α-ketoamide derivatives and the like (for example, see Patent literatures 2 to 6, Non-patent literatures 3 to 4) . (Patent literature 1) WO 93/23032 (Patent literature 2) JP-B-29229/1994 (Patent literature 3) EP-A-0771565 (Patent literature 4) U.S. Patent No. 6057290 (Patent literature 5) JP-A-147564/1998 (Patent literature 6) WO 92/12140 (Non-patent literature 1) Trends in Pharmacological Sciences, vol. 15, page 412, 1994 (Non-patent literature 2) Current Eye Research, vol. 10, Pages 657 to. 666, 1991 (Non-patent literature 3) The Biochemical Journal, vol. 253, pages 751 to 758, 1988 (Non-patent literature 4) Journal of Medicinal Chemistry, vol.35, pages 216 to 220, 1992 Disclosure of the Invention An object of the present invention is to provide a compound having potent calpain inhibitory activity, which is well absorbed orally and exhibits durability of good blood level. The present inventors have conducted intensive studies to create a calpain inhibitor having tissue transport and absorbability, especially good oral absorbability and durability of good blood level. The present inventors designed α-ketoamide derivatives having an amphiphatic group in the molecule thereof, and found among those compounds a compound having calpain protease inhibitory activity and good oral absorbability. They have conducted further studies and thus completed the present invention. Namely, the present invention relates to (1) A compound represented by the formula (I) wherein R1 is a lower alkyl substituted by a lower alkoxy or a heterocyclic group, or a heterocyclic group; R2 is a lower alkyl optionally substituted by a phenyl; and R3 is hydrogen, a lower alkyl optionally substituted by a halogen, a lower alkoxy or a phenyl, or a fused polycyclic hydrocarbon group, (2) the compound according to the above (1), wherein the lower alkyl represented by R1 which is substituted by a lower alkoxy is a group the formula (IIa) in which R4 is a lower alkyl, R5 is a lower alkylene, and m is an integer of 1 to 6, ( 3) the compound according to the above (1) , wherein the lower alkyl represented by R1 which is substituted by a lower alkoxy is a group of the formula (IIb) in which n is an integer of 1 to 6, (4) the compound according to the above (1), wherein the heterocyclic group which is a substituent for the lower alkyl represented by R1 is pyridyl optionally having a lower alkyl, (5) the compound according to the above (1), wherein the hetero atom of the heterocyclic group represented by R1 is an oxygen atom, (6) the compound according to any one of the above (1) to ( 5) , wherein the lower alkyl represented by R3 is cyclopropyl, (7) ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3- (cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 2-methoxyethyl ester, ((1S)-1-((((1S)-1-benzyl-2,3-dioxo- 3-(cyclopropylamino)propyl)amino)carbonyl) - 3 - methylbutyl)carbamic acid 5-methoxy-3-oxapentyl ester, ((1S)-1-((((1S)-1-benzyl-2,3-dioxo- 3-(cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 8-methoxy-3,6-dioxaoctyl ester, ((1S)-1-((((1S)-1-benzyl-2,3-dioxo- 3-(cyclopropylamino)propyl)amino)carbonyl) - 3 - methylbutyl) carbamic acid ll-methoxy-3 , 6 , 9-trioxaundecanyl ester, or ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2, 3- dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-(pyridin-2-yl)ethyl ester, (8) a medicament comprising the compound according to the above (1) or (7), (9) the medicament according to the above (8) , which is a calpain inhibitor, (10) the medicament according to the above (9) , which is a therapeutic agent for a disease related to calpain, and (11) the medicament according to the above (10), wherein the disease related to calpain is ischemic disease, immunologic disease, multiple sclerosis, Alzheimer's disease, osteoporosis, diseases caused by brain tissue damage, cataract, glaucoma, retinal disease, retinochoroiditis, posterior eyeball complications due to photocoagulation or a disease involving neovascularization. The compound of the present invention is a calpain inhibitor which is well absorbed orally and exhibits durability of good blood level, and thus said compound can be used as an agent for prophylaxis or treatment of diseases related to calpain such as ischemic disease, immunologic disease, multiple sclerosis, Alzheimer's disease, osteoporosis, diseases caused by brain tissue damage, cataract, glaucoma, retinochoroiditis flisease (diabetic retinopathy, retinal vein occulusion, macular degeneration, retinitis pigmentosa, hypertensive retinopathy, retinal detachment, etc.), posterior eyeball complications due to photocoagulation (e.g. macular edema, retinal detachment, optic neuritis, visual field defect, light sense defect, dyschromatopsia, etc.), a disease involving neovascularization and the like. Since the compound of the present invention has high oral absorbability, a medicament containing the compound of the present invention can be administered orally. In addition, the compound of the present invention has low toxicity, and thus can be used safely. Brief Description of the Accompanying Drawing Fig. 1: A graph showing viable cell count in the ganglion cell layer after 7-day retinal ischemia reperfusion in rats. Each column represents the mean ± S.E. In the graph, "Normal" means a normal group (n=8), "Control" means a control group (n=8) , and "Compound 17" means a group to which compound 17 is administered (n=9). The symbol (*) shows significant difference (P control group. Best Mode for Carrying Out the Invention In the above formula (I), preferable examples of lower alkyl as the lower alkyl substituted by a lower alkoxy or a heterocyclic group represented by R1 include a straight or branched C1-6 alkyl group, specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, 1-methylbutyl, 2-methylbutyl, 1,2-dimethylpropyl, hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpenty1, 4-methylpenty1, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1-ethyl-2-methylpropyl, 1,1,2-trimethylpropyl, etc. More preferable examples of the lower alkyl for R1 include a straight or branched C2-3 alkyl group , and the most preferable example includes ethyl. A preferable example of the lower alkoxy which is a substituent for the lower alkyl represented by R1 includes a C1-6 lower alkoxy such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy, neopentyloxy, tert-pentyloxy, 1-methylbutoxy, 2-methylbutoxy, 1,2-dimethylpropoxy, hexyloxy, 1-methylpentyloxy, 2-methylpentyloxy, 3-methylpentyloxy, 4-methylpentyloxy, 1,1-dimethylbutoxy, 1,2-dimethylbutoxy, 1,3-dimethylbutoxy, 2,2-dimethylbutoxy, 2,3-dimethylbutoxy, 3,3-dimethylbutoxy, 1-ethylbutoxy, 2-ethylbutoxy, l-ethyl-2-methylpropoxy, 1,1,2-trimethylpropoxy, etc. Said alkoxy groupwhich is further substituted by said lower alkoxy may be used preferably. A preferable example of the lower alkyl represented by R1 which is substituted by a lower alkoxy includes a group the formula (Ha) in which R4 is a lower alkyl, R5 is a lower alkylene, and m is an integer of 1 to 6, and more preferable example includes a group of the formula (IIb) in which n is an integer of 1 to 6. Examples of the lower alkyl represented by R4 in the above formula (IIa) include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, etc., preferably methyl, isopropyl or tert-butyl, and more preferably methyl. A preferable example of the lower alkylene represented by R5 in the above formula (IIa) includes a C1-4 alkylene, specifically methylene, ethylene, trimethylene and tetramethylene, and a more preferable example is ethylene. The lower alkylene represented by R5 may have a substituent. Examples of the substituent include methyl, ethyl, etc. In the above formula (IIa), m is an integer of 1 to 6, preferably an integer of 2 to 5. In the above formula (IIb), n is an integer of 1 to 6, preferably an integer of 1 to 5, and more preferably an integer of 2 to 5. A preferable example of the heterocyclic group which is a substituent for the lower alkyl represented by R1 includes a pyridyl optionally having a lower alkyl. Examples of the pyridyl include 2-pyridyl, 3-pyridyl and 4-pyridyl. A preferable example of the lower alkyl optionally included in said pyridyl is a C1-3 lower alkyl, specifically, methyl, ethyl, propyl, isopropyl, etc. Examples of the heterocyclic group represented by R1 include 5- to 7-membered aromatic group containing one to three atom(s) identically or differently selected from the group consisting of sulfur, oxygen and nitrogen, or partially or fully reduced, saturated heterocyclic group, and specific examples thereof include furyl, thienyl, pyrrolyl, azepinyl, pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, 1,2,3-oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyranyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, morpholinyl, thiomorpholinyl, pyrrolidinyl, pyrrolinyl, imidazolidinyl, pyrazolidinyl, piperidinyl, piperazinyl, oxazolidinyl, isoxazolidinyl, thiazolidinyl, pyrazolidinyl. tetrahydrofuranyl, tetrahydropyranyl, tetrahydrothiophenyl, etc. , preferably saturated heterocyclic group, more preferably 5- to 7-membered saturated heterocyclic group containing oxygen atom(s), and most preferably tetrahydrofuranyl, tetrahydropyranyl, etc. Examples of the lower alkyl represented by R2 are the same as the said lower alkyl as the lower alkyl substituted by a lower alkoxy or a heterocyclic group represented by R1, and include preferably methyl, ethyl and isobutyl. The lower alkyl represented by R2 is preferably substituted by a phenyl group. Preferable examples of such phenyl-substituted lower alkyl group include benzyl, phenethyl, etc. Examples of the lower alkyl represented by R3 are the same as the said lower alkyl as the lower alkyl substituted by a lower alkoxy or a heterocyclic group represented by R1, and may include a cycloalkyl group. Such cycloalkyl group can be cyclopropane, cyclobutane, cyclopentane, cyclohexane, etc., among which cyclopropane and cyclobutane are preferable. Examples of the halogen by which the above lower alkyl group may be substituted include fluorine, chlorine, bromine, etc., among which fluorine is preferable. Examples of the fused polycyclic hydrocarbon group include indanyl, indenyl, naphthyl, pentalenyl, azulenyl, etc. , among which indanyl is preferable. In addition, the compounds of the present invention include a variety of solvates, polymorphs and pro-drugs. The compounds of the present invention can be prepared, for example, according to the following method. (wherein R is a protecting group, and other groups have the same meaning as defined above) Step a is a process which comprises adding a protecting group into an amino group of amino acids of the formula (III) , converting the protected product into a mixed anhydride, and reducing the mixed anhydride with a reducing agent to yield a compound of the formula (V) (hereinafter referred to as compound (V)). The above-mentioned addition and deprotection procedures of the protecting group(s) can be carried out by the conventional method. Examples of such protecting groups used are formyl, optionally substituted C1-6 alkylcarbonyl (e.g. acetyl, propionyl, etc.), optionally substituted phenylcarbonyl, optionally substituted C1-6 alkyl-oxycarbonyl (e.g. methoxycarbonyl, ethoxycarbonyl, tert-butoxycarbonyl, etc.), optionally substituted phenyloxycarbonyl and optionally substituted C7-10 aralkyloxycarbonyl (e.g. phenyl-C1-4 alkyloxycarbonyl such as benzyloxycarbonyl, etc.) . As the substituent, halogen (e.g. fluorine, chlorine, bromine, iodine, etc. ) , nitro or the like is used, and the number of such substituents is approximately 1 to 3. Preferable substituent may be tert-butoxycarbonyl (Boc). Examples of the reducing agent used in the above reaction include lithium aluminum hydride, sodium borohydride, sodium bis(2-methoxyethoxy)aluminum hydride or the like, among which sodium borohydride is preferable. The reaction temperature is -40°C to 30°C, preferably -20°C to 0°C. The compound (V) may be prepared by adding an amino-protecting group to an amino alcohol of the formula (IV) in a similar manner (step a'). Step b is a process of oxidizing a compound (V) with dimethyl sulfoxide (DMSO) in the presence of an activating reagent for DMSO to yield a compound of the formula (VI) (hereinafter referred to as compound (VI) ) . The DMSO oxidation can be carried out by the conventional method. For example, the compound (V) is dissolved in DMSO alone or in a mixture of DMSO and a solvent not inhibiting the oxidation (e.g. tetrahydrofuran, dichloromethane, chloroform, ethyl acetate, benzene, ether, etc.), and diisopropylethylamine is usually added thereto in an amount of approximately 1- to 10-fold in a molar ratio per one mole of compound (V) . The amount of DMSO used in the above reaction is approximately 1 to 20 mL to 1 g of compound (V). As the above activating reagent for DMSO, there are advantageously employed sulfur trioxide- pyridine complex, oxalyl chloride, dicyclohexylcarbodiimide, acetic anhydride or the like. Inter alia, sulfur trioxide-pyridine complex is preferably used. Step c is a process of preparing a compound of the formula (VII) (hereinafter referred to as compound (VII)) as a diastereomer mixture, which comprises treating a compound (VI) with sodium hydrogen sulfite, reacting the product with sodium cyanide to yield a cyanohydrin compound, hydrolyzing the cyanohydrin compound with an acid or alkali catalyst without purification to yield a diastereomer mixture of α-hydroxy-β-amino acid, and adding again the above amino-protecting group to the α-hydroxy-β-amino acid in a similar manner. This hydrolysis reaction is carried out by heating or by heating under reflux with an acid (e.g. hydrochloric acid, sulfuric acid, acetic acid, formic acid, etc. ) or an alkali (e.g . sodium hydroxide, potassium hydroxide, barium hydroxide, etc.) . The heating temperature is about 50°C to about 100°C. As the solvent, a mixture of water and an organic solvent (e.g. dioxane , tetrahydrofuran, etc.) is preferably used. Step d is a process of condensing a compound (VII) with a variety of amines to yield a compound of the formula (VIII) (hereinafter referred to as VIII). As to an amine, a suitable amine can be appropriately selected depending on the objective compound. Examples of such amines include ethylamine, propylamine, cyclopropylamine, butylamine, cyclobutylamine, methoxyethylamine, 2-phenoxyethylamine, 2-aminoindane, 2,2,2-trifluoroethylamine or the like. It is preferable to carry out the above condensation in the presence of a dehydrative condensing agent such as 1 - ethyl - 3 - (3 - dimethylaminopropyl) carbodiimide hydrochloride, N,N-dicyclohexylcarbodiimide, etc. Examples of the organic solvent used in the condensation reaction include N,N-dimethylformamide, DMSO, tetrahydrofuran, dichloromethane, methanol, ethanol, benzene, toluene, ethyl acetate, etc., and a mixture thereof, among which N,N-dimethylformamide is preferable. The reaction temperature is within the range of ice-cooling to room temperature. The step e is a process of deprotecting amino-protecting group(s) of a compound (VIII) under acidic condition with hydrochloric acid to yield an amine hydrochloride of the formula (IX) (hereinafter referred to as compound (IX)). Such deprotection of amino-protecting group(s) can be carried out by the conventional method. For example, the compound (VIII) is dissolved in an organic solvent which is commonly used, and then the solution is stirred in the presence of an acid to remove the amino-protecting group(s). Examples of the acid include hydrochloric acid, trifluoroacetic acid, p-toluenesulfonic acid or the like. Alternatively, commercially available HCl/ethyl acetate or HCl/dioxane may be used to remove amino-protecting group(s) . The reaction temperature is within the range of ice-cooling to room temperature. Step f is a process of condensing a compound of the formula (IX) with a compound of the formula (X) (hereinafter referred to as compound (X) ) in the presence of triethylamine to yield a compound of the formula (XI) (hereinafter referred to as compound (XI). The above compound (X) can be prepared according to the general reaction scheme given below. (wherein each symbol has the same meaning as defined above) An alcohol of the formula (XIII) (hereinafter referred to as alcohol (XIII)) is reacted with di(N-succinimidyl) carbonate to yield a mixed carbonic ester of the formula (XIV) , which is then condensed with L-leucine ethyl ester hydrochloride in the presence of triethylamine to yield a compound of the formula (XV). Alkali saponification of the compound (XV) affords a compound of the formula (XVI) (hereinafter referred to as (XVI)). Alternatively, the compound (XVI) may be obtained by direct reaction between L-leucine and chloroformate. The compound (XVI) is reacted with hydroxysuccinimide (HOSu) to yield a succinimide ester of the formula (X) (hereinafter referred to as compound (X)). Step g is a process of oxidation of a compound. (XI) to produce a compound of the formula (XII) (hereinafter referred to as compound (XII). The oxidation reaction is carried out by per se conventional methods , including those classified into (i) chromium oxidation such as pyridinium dichromate (PDC) oxidation, pyridinium chlorochrornate (PCC) oxidation, Jones oxidation and Collins oxidation, and (ii) DMSO oxidation such as Swern oxidation, DMSO/sulfur trioxide-pyridine complex oxidation, DMSO/dicyclohexcylcarbodiimide oxidation, DMSO/oxalyl chloride oxidation, Dess-Martin oxidation using Dess-Martin , periodinane, hypohalogen acid oxidation and N-halogenocarboxylic amide oxidation, among which Dess-Martin oxidation is preferable. In carrying out Dess-Martin oxidation, the compound (XI) is dissolved in a commonly used organic solvent and Dess-Martin reagent is added thereto. Examples of the commonly used organic solvents include conventional solvents not adversely affecting the reaction or a mixture thereof, such as dichloromethane, N,N- dimethylformamide, DMSO, tetrahydrofuran, methanol, ethanol, benzene, toluene, ethyl acetate or the like, among which dichloromethane is preferable. The amount of the Dess-Martin reagent is approximately 1- to 20-fold mole equivalents, preferably 1- to 3-fold mole equivalents of the compound (XI). The reaction temperature is not particularly limited, and it is within the range of ice-cooling to room temperature. The compound (XII) thus obtained can be separated and purified by conventional methods including, for example, concentration, concentration in vacuo, solvent extraction, crystallization, recrystallization, solvent transfer, chromatography or the like. The each step as mentioned above is carried out in a commonly used solvent not adversely affecting the reaction, and a mixture thereof. Examples of such a solvent not adversely affecting the reaction include dichloromethane, N,N-dimethylformamide, DMSO, tetrahydrofuran, methanol, ethanol, benzene, toluene, ethyl acetate or the like. Specific examples of compounds (I) of the formula prepared according to the above method include ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3- (ethylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 1), ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3- (ethylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid (3S)-tetrahydro-furan-3-yl ester(Compound 2), ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3- (ethylamino)propyl)amino)carbonyl)-3-methylbutyl)carbamic acid tetrahydro-4H-pyran-4-yl ester (Compound 3), ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3- (cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 4), ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3- dioxo-propyl)amino)carbonyl)-3-methylbutyl)carbamic acid (3S)-tetrahydro-furan-3-yl ester (Compound 5), ((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2,3- dioxo-propyl)amino)carbonyl)-3-methylbutyl)carbamic acid tetrahydro-4H-pyran-4-yl ester (Compound 6), ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3- (propylamine)) propyl) amino) carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 7), ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3- (cyclobutylamino) propyl) amino) carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 8), ((1S)-1-((((1S)-1-benzyl-3-butylamino-2,3- dioxo -propyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid 2-methoxyethyl ester (Compound 9), ((1S)-1-((((1S)-1-benzyl~2,3-dioxo-3-(2,2,2- trif luoroethylamino) propyl) amino) carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 10) , ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-(2- indanylamino) propyl) amino) carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 11) , ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-(2- methoxyethylamino) propyl) amino) carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 12) , ((1S)-1-((((1S)-2,3-Dioxo-3-ethylamino-1- (phenylethyl) propyl) amino) carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 13) , ((1S)-1-((((1S)-2,3-dioxo-3-ethylamino-1- (phenylethyl)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid (3S)-tetrahydro-furan-3-yl ester (Compound 14), ((1S)-1-((((1S)-2,3-dioxo-3-cyclopropylamino-1- (phenylethyl)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 15) , ((1S)-1-((((1S)-2,3-dioxo-3-cyclopropylamino-1- (phenylethyl)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid (3S)-tetrahydro-furan-3-yl ester (Compound 16), ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3- (cyclopropylamino)propyl)amino)carbony1)-3- methylbutyl) carbamic acid 5-methoxy-3-oxapentyl ester (Compound 17), ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3- (cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 8-methoxy-3,6-dioxaoctyl ester (Compound 18), ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3- (cyclopropylamino)propyl)amino)carbonyl) - 3 - methylbutyl) carbamic acid 11-methoxy-3, 6, 9-trioxaundecanyl ester (Compound 19), ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3- (cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 14-methoxy-3,6,9,12- tetraoxa-tetradecanyl ester (Compound 20), ((1S)-1-((((1S)-2,3-dioxo-1-(2-methylpropyl)-3-(2- phenoxyethyl)aminopropyl)amino)carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester(Compound 21), ((1S)-1-((((1S)-2.3-dioxo-1-(2-methylpropyl)-3-(2- phenoxyethyl)aminopropyl)amino)carbonyl)-3- methylbutyl) carbamic acid 5-methoxy-3-oxa-pentyl ester (Compound 22), ((1S)-1-((((1RS)-3-amino-1-benzyl-2,3-dioxo- propyl)amino)carbonyl)-3-methylbutyl)carbamic acid 5-methoxy-3-oxa-pentyl ester (Compound 23), ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3- dioxo-propyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-(pyridin-2-yl)ethyl ester (Compound 24), ( (lS)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3- dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-(6-methylpyridin-2-yl)ethyl ester (Compound 25), ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3- dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-(5-ethylpyridin-2-yl)ethyl ester (Compound 26), ((1S)-1-((((1S)-1-benzyl-3~(cyclopropylamino)-2,3- dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-tert-butoxyethyl ester (Compound 27), ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3- dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-isopropoxyethyl ester (Compound 28) and the like, among which compounds 4, 17, 18, 19 and 24 are preferable. These compounds of the present invention have not yet been reported in literatures, and thus are novel. As shown in Test Examples which will be hereinafter described, the compounds of the present invention have an excellent calpain inhibitory activity. Accordingly, a medicament containing a compound of the present invention as active ingredient, optionally together with a combination of carriers which will be hereinafter described, is useful as a calpain inhibitor. The medicament containing a compound of the present invention is useful as a prophylactic or therapeutic agent for mammal (e.g. human, rat, mouse, rabbit, cattle, pig, dog, cat) diseases related to calpain such as ischemic disease, immunologic disease, multiple sclerosis, Alzheimer's disease, osteoporosis , diseases caused by brain tissue damage, cataract, glaucoma, retinochoroiditis disease (diabetic retinopathy, retinal vein occulusion, macular degeneration, retinitis pigmentosa, hypertensive retinopathy, retinal detachment, etc.), posterior eyeball complications due to photocoagulation (e.g. macular edema, retinal detachment, optic neuritis, visual field defect, light sense defect, dyschromatopsia, etc.), a disease involving neovascularization or the like. In addition, a compound of the present invention has excellent tissue transport and high absorbability as well as high safety with very low toxicity. The medicament containing a compound of the present invention can be administered systemically or locally. Besides oral administration. The systemic administration includes, besides oral administration, parenteral administration route such as intravenous injection, subcutaneous injection, intramuscular injection or the like. In case of the local administration, the medicament is applied via transdermal, mucous membrane, nasal or ophthalmic route, etc. The dosage form of the medicament containing a compound of the present invention includes solid preparations (e.g. powders, granules, tablets, capsules, suppositories, etc.) and liquid preparations (e.g. syrups, injections, eyedrops, nasal drops, etc.). In the production of granules or tablets, any dosage form can be prepared with the use of pharmaceutically acceptable additives such as excipients (e.g. lactose, sucrose, glucose, starch, crystalline cellulose, etc.), lubricants (e.g. magnesium stearate, talc, stearic acid, calcium stearate), disintegrators (e.g. starch, carmellose sodium, calcium carbonate, etc.), or binders (e.g. starch paste, hydroxypropylcellulose solution, carmellose solution, gum arable solution, gelatin solution, sodium alginate solution, etc.). Further, granules and tablets may be coated with a coating agent (e.g. gelatin, white sugar, gum arable, carnauba wax, etc.) or an enteric coating agent (e.g. cellulose acetate phthalate, methacrylic copolymer, hydroxypropylcellulose phthalate, carboxymethylethyl cellulose, etc.). In the production of capsules, conventional excipients such as magnesium stearate, calcium stearate, talc and light silicic acid, anhydride, etc., for improving flowability and lubricity; crystalline cellulose and lactose for increasing flowability under pressure; and the above-mentioned disintegrators are appropriately selected, and mixed or granulated homogenously with the compound of the present invention, then filled in capsules. Alternatively, the granulated products may be coated with a suitable coating agent, then filled in capsules, or may be encapsulated with an appropriate capsule base (e.g. glycerin) having increased plasticity endowed with addition of glycerin or sorbitol. If required, coloring agents, preservatives (e.g. sulfur dioxide, parabens such as methyl p-oxybenzoate, ethyl p-oxybenzoate and propyl p-oxybenzoate), etc. may be added to the capsule preparations. Enteric coated capsules, gastric resistant capsules or release controlled capsules may be formulated in addition to conventional capsule preparations. In the case of enteric coated capsule preparations, they are prepared by filling regular capsules with the compound of the present invention which is coated with an enteric coating agent or to which said appropriate excipient is added, or alternatively, they are prepared by filling capsules coated with an enteric coating agent or capsules made from an enteric polymer as a base material with the compound of the present invention optionally together with said appropriate excipient. In the production of suppositories, an appropriate suppository base (e.g. cacao butter, macrogol, etc.) can be used. In the production of syrups, stabilizers (e.g. sodium edetate, etc.), suspending agents (e.g. gum arablc, carmellose, etc.), corrigents (e.g. simple syrup, glucose, etc.), perfumes or the like can be appropriately used. Injections, eye-drops or nasal drops of the present invention can be produced by dissolving or dispersing the compound of the present invention in a solution containing an appropriate isotonic (e.g. sodium chloride, potassium chloride, glycerin, mannitol, sorbitol, boric . acid, borax, glucose, propylene glycol, etc.), buffer (e.g. phosphate buffer, acetate buffer, borate buffer, carbonate buffer, citrate buffer, Tris buffer, glutamate buffer, e-aminocapronate buffer, etc.), preservative (e.g. methyl p-oxybenzoate, ethyl p-oxybenzoate, propyl p-oxybenzoate, chlorobutanol, benzyl alcohol, benzalkonium chloride, sodium dehydroacetate, sodium edetate, boric acid, borax, etc.), thickener (e.g. hydroxyethylcellulose, hydroxypropylcellulose, polyvinyl alcohol, polyethylene glycol, etc.), stabilizer (e.g. sodium hydrogensulfite, sodium thiosulfate, sodium edetate, sodium citrate, ascorbic acid, dibutylhydroxytoluene, etc.), pH controlling agent (e.g. hydrochloric acid, sodium hydroxide, phosphoric acid, acetic acid, etc.) or the like. Although the amount of the additive to the above injection, eye drop or nasal drop depends on the kind and the purpose of the additive to be added, it is sufficient to add the amount of the additive that can achieve the purpose. Usually, an isotonic is preferably added in an amount of about 0.5 to about 5.0 w/v % so that the osmotic pressure reaches about 229 mOsm to about 343 mOsm. Preferred concentrations of buffer, thickner and stabilizer to be added are about 0.01 to about 2.0 w/v %, about 0.01 to about 1.0 w/v % and about 0.001 to about 1.0 w/v %, respectively. A pH controlling agent is appropriately added to adjust the pH usually to about 3 to about 9, preferably about 4 to about 8. The dose of the compound of the present invention depends on the target diseases, symptom of the disease, subject to be administered, administration route or the like. For example, in the case of oral administration to an adult patient, the dose is about 1 to about 200 mg, preferably about 10 to about 100 mg for a single dose, once to several times a day. In the case of injection to an adult patient, the dose is about 0.1 to about 50 mg, preferably about 1 to about 30 mg, once a day. For topical administration to the eyes, it is preferable to administer eye drops containing usually about 0.001 to about 1.0 w/v %, preferably about 0.01 to about 0.5 w/v %, in an amount of about 20 to about 50 µL per dose, several times a day. Examples The present invention will be explained in detail by way of Reference Examples, Examples, Test Examples and Formulation Examples, however, the invention is not restricted thereto. In the analytical data of the compounds described in the Examples, melting points were determined on a Yanaco micro melting point apparatus without correction. 1H-NMR spectra were recorded on a Varian Gemini-2000 spectrometer. Chemical shifts are reported in parts per million, and coupling constants (J) are reported in hertz. Matrix-assisted laser desorption ionization time-of-flight mass spectra (MALDI-TOF-MS) were obtained on a Perseptive Voyager DE mass spectrometer, and the mass numbers were corrected with an internal standard (a-cyano-4-hydroxycinnamic acid) and displayed accurately. Reference Example 1 N- ((2-Methoxyethoxy)carbonyl)-1-leucine N-hydroxy- succinimide ester (1) To a solution of L-leucine (25 g, 0.19 mol) was dissolved in 2M NaOH (0.12 L) was slowly added 2-methoxyethyl chloroformate (30 g, 0.22 mol) and 1M NaOH at the same time under the ice-cooled condition. The mixture was stirred at room temperature for 18 hours, diluted into water (600 mL) and washed with ethyl ether (2 x 200 mL) . The aqueous phase was cooled in an ice bath and acidified to pH 3 with 6M HC1. This mixture was extracted with ethyl acetate (EtOAc) (5 x 150 mL) . The organic phase was dried over anhydrous MgSO4 and filtered, and the filtrate was concentrated in vacuo to yield N-((2- methoxyethoxy)carbonyl)-1-leucine (41 g, 92%) as a colorless oil. (2) N-((2-Methoxyethoxy)carbonyl)-1-leucine (20 g, 86 mmol) and N-hydroxysuccinimide (13 g, 0.11 mmol) were dissolved in THF (200 mL), and a suspension of 1-ehtyl-3-(3- dimethylaminopropyl)carbodiimide hydrochloride (21 g, 0.11 mol) in CH2Cl2 (200 mL) was added thereto. The mixture was stirred at room temperature for 18 hours, and concentrated in vacuo. The residue was dissolved in EtOAc (300 mL), and the solution was washed with 1M HCl (150 mL), saturated aqueous NaHCO3 (150 mL) and saturated aqueous NaCl (150 mL) , dried over anhydrous MgSO4, and concentrated in vacuo to give the title compound (27 g, 95%) as a colorless oil. 1H-NMR (300MHz,DMSO-d6) δ 0.89 (d,3H,J=6.6),0.93(d,3H,J= 6.6) , 1.57-1.84(m,3H),2.81(s,4H),3.26(s,3H),3.51(t,2H,J=4.7), 4.10(t,2H,J=4.7),4.40(m,lH),8.04(d,lH,J=8.1). Reference Example 2 (1)N-(((3S)-Tetrahydrofuran-3-yloxy)carbonyl)-1- leucine N-hydroxysuccinimide ester To a stirred solution of (S)-3-hydroxytetrahydrofuran (1.0 g, 11 mmol) in acetonitrile (50 mL) at room temperature were added N,N'-disuccinimidyl carbonate (4.3 g, 17 mmol) and triethylamine (4.4 g, 17 mmol, 4.8 mL) . The resulting mixture was stirred at room temperature for 18 hours, and concentrated in vacuo .' The residue was diluted with saturated aqueous NaHCO3 (100 mL) and extracted with EtOAc (200 mL) . The combined organic extracts were washed with saturated aqueous NaCl (100 mL), dried over anhydrous MgSO4, and concentrated in vacuo to give N-succinimidyl (3S)-3-tetrahydrofranyl carbonate (2.6 g) as a brown oil in a quantitative yield. ( 2) To a solution of L-leucine ethyl ester hydrochloride (2.7 g, 14 mmol) and triethylamine (2.9 g, 2 8 mmol) in dichloromethane (50 mL) was added a solution of N-succinimidyl (3S)-3-tetrahydrofurnaylcarbonate (2.6 g, 11 mmol) in dichloromethane (20 mL), and the mixture was stirred at room temperature for 18 hours, then concentrated in vacuo. The residue was dissolved in ethyl acetate (200 mL), and the solution was washed successively with 1M hydrochloric acid, saturated aqueous NaHCO3 and saturated aqueous NaCl, dried over anhydrous magnesium sulfate, and concentrated in vacuo. The residue was washed with hexane to give N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine ethyl ester (3.1 g, 98%) as a white solid. (3) To a solution of N-(((3S)-tetrahydrofuran-3- yloxy)carbonyl)-1-leucine ethyl ester (2.9 g, 11 mmol) in EtOH (100 mL) was added 1M NaOH (33 mL) . The mixture was stirred under ice-cooling condition for 3 hours, and then adjusted to pH 3 by the addition of HCl thereto. The solution was concentrated in vacuo, and the residue was extracted with ethyl acetate (100mL) . Then, the organic layer was separated, washed with 1M HCl and saturated aqueous NaCl, dried over anhydrous MgSO4 and concentrated in vacuo. The residue was crystallized from ethyl acetate and hexane to give N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine (2.6 g, 85%) as colorless crystals. M.p. 94.9-96.0°C (4) Following the reaction in an analogous manner to Reference Example 1(2) and using N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine in place of N-((2-methoxyethoxy)carbonyl)-1-leucine, there was obtained the title compound as a colorless oil. 1H-NMR(300MHz,DMSO-d6) δ 0.89 (d,3H,J=6.0),0.92(d, 3H, J=6.3), 1.55-1.82(m,3H),1.88 (m, 1H),2.12(m, 1H),2.81(s,4H), 3.64-3.84 (m,4H),4.39(m,lH),5.l5(m,lH),8.04(d,1H,J=7.8). Reference Example 3 N- ((Tetrahydro-4H-pyran-4-yloxy)carbonyl) -1-leucine N-hydroxysuccinimide ester (1) N-Succinimidyl tetrahydro-4H-pyran-4-ylcarbonate was obtained as a brown oil in a manner similar to Reference Example 2(1), using 4-hydroxytetrahydro-4H-pyran in place of (S)-3-hydroxytetrahydrofuran, there was obtained N-succinimidyl tetrahydro-4H-pyran-4-ylcarbonate as a brown oil. (2) Following the reaction in an analogous manner to Reference Example 2(2) and using N-succinimidyl tetrahydro- 4H-pyran-4-ylcarbonate in place of N-succinimidyl (3S)-3-tetrahydrofuranyl carbonate, there was obtained N-( (tetrahydro-4H-pyran-4-yloxy)carbonyl)-1-leucine ethyl ester as a colorless solid. (3) Working up in a manner similar to Reference Example 2(3) and using N-(5-methoxy-3-oxaopentyloxy)carbonyl)-1- leucine ethyl ester in place of N-(((3S)-tetrahydrofuran- 3-yloxy)carbonyl) -1-leucine ethyl ester, there was obtained N- ((tetrahydro-4H-pyran-4-yloxy)carbonyl)-1-leucine as a colorless solid. (4) Using N-((tetrahydro-4H-pyran-4-yloxy)carbonyl)- L-leucine) in place of N-(2-(methoxyethoxy)carbonyl)- L-leucine, a similar reaction to Reference Example 1(2) gave the title compound as a colorless oil. 1H-NMR(300MHz,DMSO-d6) δ 0.89(d,3H,J=6.0),0.92(d,3H,J= 6.3), 1.43-1.93(m,7H),2.80(s,4H),3.42(m,2H),3.78-3.82(m, 2H) , 4.39 (m,1H),4.72(m,1H),7.94(d,1H,J=7.8). Reference Example 4 N-((5-Methoxy-3-oxapentyloxy)carbonyl)-1-leucine N-hydroxysuccinimide ester (1) Following the reaction in an analogous manner to Reference Example 2(1) and using diethylene glycol monomethyl ether in place of (S)-3-hydroxytetrahydrofuran, there was obtained 5-methoxy-3-oxapentyl N-succinimidyl carbonate as a colorless oil. (2) Following the reaction in an analogous manner to Reference Example 2(2) and using 5-methoxy-3-oxapentyl N-succinimidyl carbonate in place of N-succinimidyl (3S)-3-tetrahydrofuranyl carbonate, there was obtained N- ((5-methoxy-3-oxapentyloxy)carbonyl) -1-leucine ethyl ester as a colorless oil. (3) Following the reaction in an analogous manner to Reference Example 2(3) and using N- ((5-methoxy-3- oxapentyloxy)carbonyl)-1-leucine ethyl ester in place of N- ((3S)-tetrahydrof uran-3-yloxycarbonyl)-1-leucine ethyl ester, there was obtained N-((5-methoxy~3- oxapentyloxy)carbonyl)-1-leucine as a colorless oil. (4) Following the reaction in an analogous manner to Reference Example 1(2) and using N- ((5-methoxy-3- oxapentyloxy)carbonyl)-1-leucine in place of N-((2- methoxyethoxy)carbonyl-1-leucine, there was obtained the title compound as a colorless oil. 1H-NMR(300MHz,DMSO-d6) δ 0.90(dd,6H,J=9.5,6.5),1.56-1.80(m. 3H),2.80(s,4H),3.24(s,3H),3.41-3.46(m,2H),3.50-3.54(m,2H), 3.56-3.60(m,2H),4.08-4.11(m,2H),4.39(m,1H),8.05(d,1H,J=7.8). Reference Example 5 N-((8-Methoxy-3,6-dioxaoctyloxy)carbonyl)-1-leucine N-hydroxysuccinimide ester (1) Following the reaction in an analogous manner to Reference Example 2(1) and using triethylene glycol monomethyl ether in place of (S)-3-hydroxytetrahydrofuran, there was obtained 8-methoxy-3,6-dioxaoctyl N-succinimidyl carbonate as a colorless oil. (2) Following the reaction in an analogous manner to Reference Example 2(2) and using 8-methoxy-3,6-dioxaoctyl N- succinimidyl carbonate in place of N-succinimidyl (3S)-3-tetrahydrofuranyl carbonate, there was obtained N-((8-methoxy-3,6-dioxaoctyloxy)carbonyl)-1-leucine ethyl ester as a colorless oil. (3) Following the reaction in an analogous manner to Reference Example 2(3) and using N- (8-methoxy-3,6- dioxaoctyloxy)carbonyl)-1-leucine ethyl ester in place of N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl-1-leucine ethyl ester, there was obtained N-((8-methoxy-3,6- dioxaoctyloxy)carbonyl)-1-leucine as a colorless oil. (4) Following the reaction in an analogous manner to Reference Example 1(2) and using N-((8-methoxy-3,6- dioxaoctyloxy)carbonyl)-1-leucine in place of N-((2- methoxyethoxy)carbonyl)-1-leucine, there was obtained the title compound as a colorless oil. 1H-NMR(300MHz,DMSO-d6) δ 0.89(d,3H,J=6.3),0.92(d,3H,J=6.3), 1.56-1.82(m,3H),2.81(s,4H),3.24(s,3H),3.43(m,2H),3.52(m, 6H),3.59(m,2H),4.10(m,2H),4.40(m,1H),8.06(d,1H,J=7.8). Reference Example 6 N-((11-Methoxy-3,6,9-trioxaundecanyloxy)carbonyl)-1- leucine N-hydroxysuccinimide ester (1) Following the reaction in an analogous manner to Reference Example 2(1) and using tetraethylene glycol monomethyl ether in place of (S)-3-hydroxytetrahydrofuran, there was obtained 111-methoxy-3, 6,9-trioxaundecanyl N-succinimidyl carbonate as a colorless oil. (2) Following the reaction in an analogous manner to Reference Example 2(2) and using 111-methoxy-3, 6 , 9-trioxaundecanyl N-succinimidyl carbonate in place of N-succinimidyl (3S)-3-tetrahydrofurahyl carbonate, there was obtained N-((111-methoxy-3,6,9- trioxaundecanyloxy)carbonyl-1-leucine ethyl ester as a colorless oil. (3) Following the reaction in an analogous manner to Reference Example 2(3) and using N- ((111-methoxy-3,6,9- trioxa-undecanyloxy)carbonyl-1-leucine ethyl ester in place of N- (((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine ethyl ester, there was obtained N- ((111-methoxy-3,6,9- trioxa-undecanyloxy)carbonyl)-1-leucine as a colorless oil. (4) Following the reaction in an analogous manner to Reference Example 1(2) and using N- ((111-methoxy-3,6,9- trioxaundecanyloxy)carbonyl)-1-leucine in place of N-((2- methoxyethoxy)carbonyl)-1-leucine, there was obtained the title compound as a colorless oil. 1H-NMR(300 MHz,DMSO-d6) δ 0. 91 (dd, 6H, J=9 . 3 , 6 . 3) , 1. 56-1. 77(m, 3H),2.81(s,4H),3.24(s,3H),3.41-3.44(m,2H),3.49-3.52(m,10H) , 3.59(t,2H,J=4.7),4 . 08-4.11(m,2H),4.38(m,1H),8.06(d,1H,J=7 . 8 ). Reference Example 7 N-((14-Methoxy-3,6,9,12-tetraoxatetradecanyloxy)carbonyl)- L-leucine N-hydroxysuccinimide ester (1) Following the reaction in an analogous manner to Reference Example 2(1) and using pentaethylene glycol monomethyl ether in place of (S)-3-hydroxytetrahydrofuran, there was obtained 14-methoxy-3 , 6 , 9 ,12-tetraoxa-tetradecanyl N-succinimidyl carbonate as a colorless oil. (2) Following the reaction in an analogous manner to Reference Example 2(2) and using 14-methoxy-3 , 6,9,12-tetraoxa-tetradecanyl AT-succinimidyl carbonate in place of N-succinimidyl (3S)-3-tetrahydrofuranyl carbonate, there was obtained N-((14-methoxy-3,6,9,12- tetraoxa-tetradecanyloxy)carbonyl)-1-leucine ethyl ester as a colorless oil. (3) Following the reaction in an analogous manner to Reference Example 2(3) and using N- ((14-methoxy-3,6,9,12- tetraoxa-tetradecanyloxy)carbonyl-1-leucine ethyl ester in place of N-( (3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine ethyl ester, there was obtained N- ((14-methoxy-3,6,9,12- tetraoxa-tetradecanyloxy)carbonyl)-1-leucine as a colorless oil. (4) Following the reaction in an analogous manner to Reference Example 1(2) and using N- ((14-methoxy-3,6,9,12- tetraoxa-tetradecanyloxy)carbonyl L-leucine in place of N-((2-methoxyethoxy)carbonyl) -1- leucine, there was obtained the title compound as a colorless oil. 1H-NMR(300MHz,DMSO-d6) δ 0.89(d,3H,J=6.6),0.92(d,3H,J=6.3) , 1.57-1.82(m,3H),2.81(s.4H),3.24(s,3H),3.43(m,2H),3.51(m, 14H),3.59(m,2H),4.10(m,2H),4.40(m,1H),8.05(d,1H,J=7.8) . Reference Example 8 (3S) -3-Amino-N-ethyl-2-hydroxy-4-phenylbutanamide hydrochloride (1) To a solution of L-phenylalaninol (50 g, 66 mmol) in tetrahydrofuran (1.3 L) and water (630 mL) , a solution of di-t-butyl dicaxbonate (140 g, 0.67 mol) in tetrahydrofuran (500 mL) and 1M NaOH (660 mL) were added slowly at the same time under ice-cooled condition. The mixture was stirred at room temperature for 18 hours, concentrated in vacuo, and diluted with ethyl acetate (EtOAc) (1 L) . The solution was washed with 1M HCl, saturated aq. NaHCO3 and saturated aq. NaCl, dried over anhydrous MgSO4, and concentrated in vacuo. The resulting white solid was recrystalized from ethyl acetate/hexane (1:10). The crystal was filtered off to give N- (tert-butoxycarbonyl) - L-phenylalaninol (70 g, 84%) as colorless crystals. (2) N-(tert-Butoxycarbonyl) -1-phenylalaninol (69 g, 0.28 mol) was dissolved in DMSO (280 mL) and CH2Cl2 (140 mL), and the solution was in an ice-bath. N,N- diisopropylethylamine (106 g, 0.82 mol) and a suspension of purified sulfur trioxide pyridine complex (130 g, 0.82 mol) in DMSO (100 mL) were added thereto. The mixture was stirred for 1 hour under the same condition. The reaction mixture was diluted with EtOAc (1.5 L) , and the solution was washed with 1M HCl, saturated aqueous NaHCO3 and saturated aqueous NaCl, dried over anhydrous MgSO4, and concentrated in vacuo. The residue was crystallized from a mixture of hexane and EtOAc to give N- (tert-butoxycarbonyl) - L-phenylalaninal (53 g, 77%) as colorless crystals. (3) N- (tert-Butoxycarbonyl) -1-phenylalaninal (17 g, 67 mmol) was dissolved in MeOH (100 mL) and chilled to 5 °C. Sodium bisulfite (7.0 g, 67 mmol) was dissolved in water (150 mL) and chilled to 5 °C. The solution was added to the aldehyde solution, and the mixture was stirred at 5°C for 18 hours. NaCN (4.0 g, 81 mmol) was dissolved in water (100 mL) and added with EtOAc (300 mL) to the above mixture. The reaction solution was stirred at room temperature for 5 hours. The organic layer was collected, dried over anhydrous MgSO4, and concentrated in vacuo to yield the cyanohydrin as a colorless oil. The cyanohydrin was dissolved in 1,4-dioxane (250 mL) and concentrated HCl (250 mL) , and 10 mL of anisole was added. The solution was gently refluxed for 18 hours, allowed to cool to room temperature and then concentrated in vacuo to give a brown semi-solid. The residue was dissolved in water (100 mL) and washed with ethyl ether (3 x 50 mL) . The aqueous phase was then placed on a Dowex 50X8- column (100-200 mesh, H+ form; 25 x 1.8 cm). The column was washed with water until the pH 5.5, and eluted with 2M ammonium hydroxide (ca. 1.5 L) . The eluent was concentrated in vacuo to yield (3S)-3-amino-2-hydroxy- 4-phenylbutanoic acid (12 g, 88%) as a white solid. (4) (3S) -3-Amino-2-hydroxy—4-phenylbutyric acid (11 g, 56.34 mmol) was dissolved in 1M NaOH (70 mL), and to this solution was added a solution of di-t-butyl dicarbonate (12 g, 57 mmol) in dioxane (70 mL) . The mixture was stirred at room temperature for 18 hours while the pH was maintained between 10 and 11 with 1M NaOH. The mixture was diluted with water (600 mL) , and washed with diethyl ether (2 x 200 mL) . The aqueous phase was chilled in an ice bath and acidified to pH 2 with 1M HCl. This mixture was extracted with ethyl ether (3 x 250 mL) . The organic phase was dried over anhydrous MgSO4 and concentrated in vacuo to yield (3S)-3-(tert- butoxycarbonylamino) -2-hydroxy-4- phenylbutanoic acid (12 g, 72%) as a mixture of diastereomer which was a colorless solid. (5) (3S)-3-(tert-Butoxycarbonylamino)-2-hydroxy-4- phenylbutanoic acid ( 6 . 3 g, 21 mmol) and 1-hydroxybenzotriazole (HOBt) (3.0 g, 22. 4 mmol) were dissolved in DMF (45mL) and cooled in an ice bath. 1-Ethyl-3-(S-dimethylaminopropyl)carbodi- imide hydrochloride (EDC) (4.6 g, 24 mmol) was added, followed by aqueous ethylamine solution (3.0 mL). The solution was stirred for 18 hours. The solution was diluted into EtOAc (200 mL) and washed with 1M HCl, saturated aqueous NaHCO3, and saturated aqueous NaCl. The organic layer was dried over anhydrous MgSO4 and concentrated in vacuo to yield ((1S)-1-benzyl-3-ethylamino-2-hydroxy-3-oxo- propyl)carbamic acid 1,1- dimethylethyl ester (5.8 g, 84%) as a white solid. (6)((1S)-1-Benzyl-3-ethylamino-2-hydroxy-3- oxopropyl)carbamic acid 1,1-dimethylethyl ester (5.5 g, 17 mmol) was dissolved in 4N HCl/dioxane (65 mL) and was stirred for 3 hours at room temperature. The solution was concentrated in vacuo to yield the title compound as a white solid (4.4 g) in a quantitative yield. M.p. 162.8-163.3°C. (Major)1H-NMR(300MHz,DMSO-d6) δ 1.02(t,3H,J=7.2),2.93(m,2H), 3.05-3.20(m,2H),3.60(m,1H),3.88 (m,1H),6.75 (d,1H,3=6.0), 7.19-7.37(m,5H),8.08(m,1H),8.17(br s,3H). (Minor ) 1H-NMR(300MHz ,DMSO-d6) δ 0 . 97 (t, 3H, J=7 . 4) , 2 . 80(d, 2H, J =6.9),3.00(m,2H),3.69(m,1H),4.26(m,1H).6.53(d,1H,J=5.4), 7.19-7.37(m,5H),8.03(t,1H,J=5.7),8.17(br s,3H). Reference Example 9 (3S)-3-Amino-N-cyclopropyl-2-hydroxy-4-phenylbutanamide hydrochloride Following the reaction in an analogous manner to Reference Example 8(5) and using cyclopropylamine in place of aqueous ethylamine, there was obtained ((1S)-1-benzyl-3- cyclopropylamino-2-hydroxy-3-oxopropyl)carbamic acid 1,1-dimethylethyl ester as a white solid. Following the reaction in an analogous manner to Reference Example 8(6) and using ((1S)-1-benzyl-3- cyclopropylamino-2-hydroxy-3-oxopropyl)carbamic acid 1,1-dimethyl ester in place of ((1S)-1-benzyl-3- ethylamino-2-hydroxy-3-oxopropyl)carbamic acid 1,1- dimethyl ethyl ester, there was obtained the title compound as a white solid. M.p. 162.9-163.3°C 1H-NMR(300MHz ,DMSO-d6) δ 0.44(m,2H),0.57(m,2H),2.50(m,0.5H), 2.65(m,0.5H),2.82(d,1H,J=6.9),2.94(m,1H),3.60(m,0.5H),3.70 (m,0.5H),3.87(m,0.5H),4.26(d,0.5H,J=2.4),6.45(br s,0.5H), 6.69(br s,0.5H),7.23-7.35(m,5H),7.99(d,0.5H,J=4.2),8.08(br s,1.5H),8.09(d,0.5H,J=4.5),8.23(br s,1.5H). Reference Example 10 (3S)-3-Amino-2-hydroxy-4-phenyl-W-propylbutanamide hydrochloride Following the reaction in an analogous manner to Reference Example 8(5) and using propylamine in place of aqueous ethylamine, there was obtained ((1S)-1-benzyl-2-hydroxy-3-oxo-3- (propylamino)propyl)carbamic acid 1,1-dimethylethyl ester as a white solid. Following the reaction in an analogous manner to Reference Example 8(6) and using ((1S)-1-benzyl-2-hydroxy- 3-OXO-3-(propylamino)propyl)carbamic acid 1,1-dimethylethyl ester in place of ((1S)-1-benzyl-3-ethylamino-2-hydroxy-3- oxopropyl)carbamic acid 1,1-dimethylethyl ester, there was obtained the title compound as a white solid. M.p. 127.8-129.5°C 1H-NMR(300MHz ,DMSO-d6) δ 0.82(m,3H) , 1. 35-1. 47(m, 2H) ,2.82 (m, 0.5H),2.95(m,3H),3.09(m,0.5H),3.58(m,0.5H),3.70(m,0.5H), 3.92(m,0.'5H),4.31(m,0.5H) , 6 . 55 (d, 0 . 5H, J=4 .8) , 6 . 77 (d, 0 . 5H, J=6.6),7.21-7.36(m,5H),7.98-8.15(m,2.5H),8.24(br s,1.5H). Reference Example 11 (3S) -3- Amino-AT-cyclobutyl- 2 -hydroxy- 4 -phenylbutanamide hydrochloride Following the reaction in an analogous manner to Reference Example 8(5) and using cyclobutylamine in place of aqueous ethylamine, there was obtained ((1S)-1-benzyl-3- cyclobutylamino - 2 -hydroxy- 3 - oxopropyl) carbamic acid 1,1- dimethylethyl ester as a white solid. Following the reaction in an analogous manner to Reference Example 8(6) and using ((1S)-1-benzyl-3- cyclobu tylamino - 2 -hydroxy- 3 - oxopropyl) carbamic acid 1,1-dimethylethy1 ester in place of ((1S)-1-benzyl-3- ethylamino-2-hydroxy-3-oxopropyl) carbamic acid 1,1- dimethylethyl ester, there was obtained the title compound as a white solid. M.p.l62.5-163°C. 1H-NMR(300 MHz,DMSO-d6) δ 1.59(m,2H),1.88-2.18(m,4H),2.80(d, 1H,J=6.6),2.91(m,1H),3.58(m,0.5H),3.69(m,0.5H),3.87(m, 0.5H),4.08(m,0.5H),4.16-4.24(m,1H),6.50(d,0.5H,J=5.4), 6.72(d,0.5H,J=6.0),7.21-7.33(m,5H),8.05(br s,1.5H),8.19(d, 0.5H,J=7.8),8.20(br s,1.5H),8.29(d,0.5H,J=8.1). Reference Example 12 (3S)-3-Amino-N-butyl-2-hydroxy-4-phenyl-butanamide hydrochloride Following the reaction in an analogous manner to Reference Example 8(5) and using butylamine in place of aqueous ethylamine, there was obtained ((1S)-1-benzyl-3-butylamino- 2-hydroxy-3-oxopropyl)carbamic acid 1,1-dimethylethy1 ester as a white solid. Following the reaction in an analogous manner to Reference Example 8(6) and using ((1S)-1-benzyl-3-butylamino- 2-hydroxy-3-oxopropyl)carbamic acid 1,1-dimethylethyl ester in place of ((1S)-1-benzyl-3-ethylamino-2-hydroxy-3- oxopropyl)carbamic acid 1,1-dimethylethyl ester, there was obtained the title compound as a white solid. M.p. 141.0-141.4°C 1H-NMR(300MHz,DMSO-d6) δ 0 .86 (m, 3H) , 1.16-1. 47(m, 4H) , 2 . 80 (m, 0.5H),2.99(m,3H).3.13(m,0.5H),3.57(m,0.5H),3.70 (m,0.5H), 3.92(m,0.5H),4.30(m,0.5H),6.53(br s,0.5H),6.77(d,0.5H,J= 6.6),7.19-7.39 (m,5H),7.97-8.15(m,2.5H),8.22(s,1.5H). Reference Example 13 (3S)-3-Amino-2-hydroxy-4-phenyl-N~ (2,2,2- trifluoroethyl)butanamide hydrochloride Following the reaction in an analogous manner to Reference Example 8(5) and using 2 , 2 , 2-trif luoroethylamine in place of aqueous ethylamine, there was obtained ((1S)-1- benzyl-2-hydroxy-3-oxo-3-(2,2,2- trifluoroethylamino)propyl)carbamic acid 1,1-dimethylethy1 ester as a white solid. Following the reaction in an analogous manner to Reference Example 8(6) and using ((1S)-1-benzyl-2-hydroxy-3-oxo-3-(2,2,2- trifluoroethylamino)propyl)carbamic acid 1,1-dimethylethyl ester in place of (((1S)-1-benzyl-3-ethylamino-2-hydroxy- 3-oxopropyl)carbamic acid 1,1-dimethylethyl ester, there was obtained (3S)-3-amino-2-hydroxy-4-phenyl-N-(2,2,2- trifluoroethyl)butanamide hydrochloride as a white solid. M.p. 103.0-108.5°C 1H-NMRt300MHz,DMSO-d6) δ 2.71-2.85(m,1H),2.88-2.97(m,1H), 3.60-3.82(m,2.5H),3.91-4.05(m,1H),4.45(m,0.5H),6.75(d,0.5H, J=5.7),6.98(d,0.5H,J=6.3),7.20-7.35(m, 5H),8.12 (brs,1.5H), 8.25(br s,1.5H),8.70(m,1H). Reference Example 14 (3 S) - 3 - Amino - 2 - hy dr oxy -N- (2 -indany 1) - 4 - phenylbutanamide hydrochloride Following the reaction in an analogous manner to Reference Example 8(5) and using 2-aminoindane in place of aqueous ethylamine, there was obtained ((1S)-1-benzyl-3- (2-indanylamino)-2-hydroxy-3-oxo-propyl)carbamic acid 1,1- dimethylethyl ester as a white solid. Following the reaction in an analogous manner to Reference Example 8(6) and using ((1S)-1-benzyl-3- (2-indanylamino)-2-hydroxy-3-oxopropyl)carbamic acid 1,1- dimethylethyl ester in place of ((1S)-1-benzyl-3- ethylamino- 2-hydroxy-3-oxo- propyl)carbamic acid 1,1-dimethylethyl ester, there was obtained (3S) -3-amino-2-hydroxy-N- (2-indanyl) -4- phenylbutanamide hydrochloride as a white solid. M.p. 183.0-184.8°C 1H-NMR(300MHz ,DMSO-d6) δ 2 . 76-2.96(m,4H),3.01-3.18(m,2H), 3.62(m,0.5H),3.74(m,0.5H),3.92(m,0.5H),4.25-4.39(m,1H), 4.49(m,0.5H),6.48(d,0.5H,J=5.7),6.72(d,0.5H,J=5.7),7.13- 7.35(m,9H),8.15(m,3.5H),8.26(d,0.5H,J=7.2). Reference Example 15 (3S)-3-Amino-2-hydroxy-N- (2-methoxyethyl) - 4 - phenylbutanamide hydrochloride Following the reaction in an analogous manner to Reference Example 8(5) and using methoxyethylamine in place of aqueous ethylamine, there was obtained ((1S)-1-benzyl-2- hydroxy-3-(2-methoxyethyl)-3-oxopropyl)carbamic acid 1,1- dimethylethyl ester as a white solid. Following the reaction in an analogous manner to Reference Example 8(6) and using ((1S)-1-benzyl-2- hydroxy-3-(2-methoxyethyl)-3-oxopropyl)carbamic acid 1,1- dimethylethyl ester in place of ((1S)-1-benzyl-3- ethylamino-2-hydroxy-3-oxopropyl)carbamic acid 1,1- dimethylethyl ester, there was obtained ((3S)-3-amino-2- hydroxy-N- ( 2-methoxyethyl) -4-phenylbutanamide hydrochloride as a white solid. M.p. 113.9-117.7°C 1H-NMR(300MHz ,DMSO-d6) δ 2.82(d, 1H, J=6.6 ),2.95 (m, 1H) , 3 .10- 3.19(m,2H),3.22(s,1.5H),3.23(s,1.5H),3.28-3.34(m,2H),3.57 (m,0.5H),3.70(m,0.5H),3.92(m,0.5H),4.32 (m,0.5H),6.59(d, 0.5H,J=4.5),6.87(d,0.5H,J=6.0),7.22-7.36(m,5H),7.92 t,0.5H, J=5.7),7.98(t.0.5H,J=5.1),8.09(br s,1.5H),8.24(br s,1.5H). Reference Example 16 (3S)-3-Amino-N-ethyl-2-hydroxy-5-phenylpentanamide hydrochloride (1) To a solution of Boc-1-homophenylalanine (20 g, 72 mmol) in dlmethoxyethane (100 mL) were added N-methylmorpholine (7.2 g, 72 mmol) and isobutyl chloroformate (9.8 g, 72 mmol) in an ice-salt bath. After 1 hour with stirring, the reaction mixture was filtered and the filtrate was cooled in an ice-salt bath, and a solution of NaBH4 (4.1 g, 107 mmol) in water (10 mL) was added, followed by water (300 mL) . The resultant precipitates were collected by filtration, and the residue was washed with water and methanol to give N- (tert-butoxycarbonyl)-1-homo-phenylalaninol (15 g, 79%) as colorless crystals. (2) Following the reaction in an analogous manner to Reference Example 8(2) and using N-(tert-butoxycarbonyl)-1- homophenylalaninol in place of N- (tert-butoxycarbonyl)- L-phenylalaninol, there was obtained N- (tert-butoxycarbonyl) - L-phenylalaninal as a colorless oil. (3) Following the reaction in an analogous manner to Reference Example 8(3) and using N-(tert-butoxycarbonyl)- L-homophenylalaninal in place of N- (tert-butoxycarbonyl)- L-homophenylalaninal, there was obtained (3S)-3-amino-2- hydroxy-5-phenylpentanoic acid as a white solid. (4) Following the reaction in an analogous manner to Reference Example 8(4) and using (3S)-3-amino-2-hydroxy- 5-phenylpentanoic acid in place of (3S)-3-amino-2-hydroxy- 4-phenylbutyric acid, there was obtained (3S)-3-(tert-butoxycarbonylamino)-2-hydroxy-5- phenylpentanoic acid as a colorless oil. (5) Following the reaction in an analogous manner to Reference Example 8(5) and using (3S)-3-(tert- butoxycarbonylamino) -2-hydroxy-5-phenylpentanoic acid in place of (3S)-3-(tert-butoxycarbonylamino)-2-hydroxy-4- phenylbutanoic acid, there was obtained ((1S)-3- ethylamino-2-hydroxy-3-oxo-1-(phenylethyl)propyl)carbamic acid 1,1-dimethylethyl ester as a white solid. (6) Following the reaction in an analogous manner.to Reference Example 8(6) and using (1S)-3-ethylamino-2- hydroxy-3-oxo-1-(phenylethyl)propyl)carbamic acid 1,1- dimethylethyl ester in place of ((1S)-1-benzyl-3- ethylamino-2-hydroxy-3-oxopropyl)carbamic acid 1,1- dimethylethyl ester, there was obtained (3S) -3-amino- N-ethyl-2-hydroxy-5-phenylpentanamide hydrochloride as a white solid. M.p. 134.4-134.9°C 1H-NMR(300 MHz ,DMSO-d6) δ 0 . 99-1. 06 (m, 3H) , 1. 65-1. 96 (m, 2H) , 2.54-2.76(m,2H),3.07-3.23(m,2H),4.15(br s,0.5H),4.25(br s, 0.5H),6.44(br s,0.5H),6.55(br s,0.5H),7.17-7.33(m,5H).7.99 (br s,1.5H),8.15(t,1H,J=6.2),8.23(br s,1.5H). Reference Example 17 (3S) -3-Amino-N-cyclopropyl-2-hydroxy-5~phenylpentanamide hydrochloride Following the reaction in an analogous manner to Reference Example 16(5) and using cyclopropylamine in place of aqueous ethylamine, there was obtained ((1S)-3- cyclopropylamino-2-hydroxy-3-oxo-1- (phenylethyl)propyl)carbamic acid 1,1-dimethylethyl ester as a white solid. Following the reaction in an analogous manner to Reference Example 16(6) and using ((1S)-3-cyclopropylamino- 2-hydroxy-3-oxo-1-(phenylethyl)propyl)carbamic acid 1,1- dimethylethyl ester in place of ((1S)-1-benzyl-3-ethylamino- 2-hydroxy-3-oxopropyl)carbamic acid 1,1-dimethylethyl ester, there was obtained (3S)-3-amino-N-cyclopropyl-2- hydroxy-5-phenylpentanamide hydrochloride as a white solid. M.p. 140.2-141.3°C 1H-NMR(300MHz,DMSO-d6) δ 0.46-0.64(m,4H),1.64-1.99(m,2H) , 2.54-2.78(m,3H),3.35(m,1H),4.13(br s,0.5H),4.26(br s,0.5H), 6.37(br s,0.5H),6.51(br s,0. 5H) , 7.17-7.33(m,5H),8.05(br s. 1.5H),8.15(d,0.5H,J=4.5 ) ,8.20(d,0.5H,J=4.8),8.27(br s, 1.5H). Reference Example 18 (3S) -3-Amino-2-hydroxy-5-methyl-N-( 2-phenoxyethyl) - hexanamide hydrochloride (1) Following the reaction in an analogous manner to Reference Example 8(1) and using L-leucinol in place of L-phenylalaninol, there was obtained N- (tert-butoxycarbonyl) - L-leucinol (70 g, 84 %) as a colorless oil. (2) Following the reaction in an analogous manner to Reference Example 8(2) and using N-(tert-butoxycarbonyl)- L-leucinol in place of N-(tert-butoxycarbonyl)-1- phenylalaninol, there was obtained N-(tert-butoxycarbonyl)- L-leucinal as a colorless oil. (3) Following the reaction in an analogous manner to Reference Examples 8(3) and 8(4) and using N-(tert- butoxycarbonyl)-1-leucinal in place of N-(tert- butoxycarbonyl)-1-phenylalaninal, there was obtained (3S)- 3-(tert-butoxycarbonylamino)-2-hydroxy-5-methylhexanoic acid as a colorless oil. (4) Following the reaction in an analogous manner to Reference Example 8(5) and using (3S)-3-(tert- butoxycarbonylamino ) -2-hydroxy- 5 -methylhexanoic acid in place of (3S)-3-(tert-butoxycarbonylamino)-2-hydroxy- 4-phenylbutanoic acid, and 2-phenoxcyethylamine in place of aqueous ethylamine, there was obtained ((1S)-2-hydroxy-1- (2-methylpropyl)-3-oxo-3-(2-phenoxyethyl)amino- propyl)carbamic acid 1,1-dimethylethyl ester as a colorless oil. (5) Following the reaction in an analogous manner to Reference Example 8(6) and using ((1S)-2-hydroxy-1-(2- methylpropyl) - 3 - oxo - 3 - ( 2 -phenoxyethyl) aminopropy 1) carbamic acid 1,1-dimethylethyl ester in place of ((1S)-1-benzyl-3- ethylamino-2-hydroxy-3-oxopropyl) carbamic acid 1,1- dimethylethyl ester, there was obtained the title compound as a white solid. M.p. 93.6-96.2°C 1H-NMR( 300MHz,DMSO-d6) δ 0 . 71-0 . 89 (m, 6H) , 1. 35-1. 47 (m, 2H) , 1.72(m,1H),3.48-3.54(m,4H),4.00-4.07(m,2H),4.12(d,0.5H,J= 3.6) ,4.33(d,0.5H,J=1.8),6.91-6.96(m,3H),7.27-7.32(m,2H), 7.95(br s,1.5H),8.19-8.29(m,2.5H). Reference Example 19 3-Amino-2-hydroxy-5-phenylpentanamide hydrochloride Following the reaction in an analogous manner to Reference Example 8(5) and using ammonia gas in place of aqueous ethylamine, there was obtained l-benzyl-3-amino-2-hydroxy- 3-oxopropyl)carbamic acid 1,1-dimethylethyl ester as a white solid. Following the reaction in an analogous manner to Reference Example 8(6) and using (1-benzyl-3-amiino—2- hydroxy—3-oxopropyl)carbamic acid 1,1-dimethylethyl ester in place of ((1S)~l-benzyl-3-ethylamino-2-hydroxy-3-oxo- propyl)carbamic acid 1,1-dimethylethyl ester, there was obtained the title compound as a white solid. 1H-NMR(300MHz,DMSO-d6) δ 2.82(m,1H),2.93(m,1H),3.61(m,1H), 3.85(m,0.5H),4.26(m,0.5H),6.48(d,0.5H,J=4.8),6.75(d,0.5H, J=5.7),7.24-7.35(m,5H),7.52(m,2H),8.04(brs,1.5H),8.17(brs, 1.5H). Reference Example 20 N-((2-(Pyridine-2-yl)ethyl)carbonyl)-1-leucine N-hydroxysuccinimide ester (1) Following the reaction in an analogous manner to Reference Example 2(1) and using (2-pyridyl)ethanol in place of (S)-3-hydroxytetrahydrofuran, there was obtained N-succinimidyl 2-(pyridin-2-yl)ethylcarbonate as a brown oil. (2) Following the reaction in an analogous manner to Reference Example 2(2) and using N-succinimidyl 2-(pyridin-2-yl)ethylcarbonate in place of N-succinimidyl (3S)-3-tetrahydrofuranyl carbonate, there was obtained N-{ (2- (pyridin-2-yl)ethyloxy)carbonyl) -1-leucine ethyl ester as a colorless oil. (3) Following the reaction in an analogous manner to Reference Example 2(3) and using N- ((2-(pyridin-2- yl)ethyloxy)carbonyl)-1-leucine ethyl ester in place of W-(((S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine ethyl ester, there was obtained N-((2-(pyridin-2- yl)ethyloxy)carbonyl)-1-leucine as a white solid. (4) Following the reaction in an analogous manner to Reference Example 1(2) and using N-((2-(pyridin-2- yl)ethyloxy)carbonyl)-1-leucine in place of N-((2- methoxyethoxy)carbonyl-L-leucine, there was obtained the title compound as a colorless oil. 1H-NMR(300 MHz,DMSO-d6) δ 0 . 82-0 . 91(m, 6H) , 1. 42-1. 76 (m, 3H) , 2. 76-2.81(m,4H),3.00-3.06 (m,2H),4.30-4.40(m,3H),7.23(dd,1H, J=7.1,5.3),7.30(d,1H,J=7.8),7.71(m,1H),7.90 (d,1H,J=8.1), 8.50(d,1H,J=4.5). Reference Example 21 N-((2-(6-Methylpyridin-2-yl)ethyloxy)carbonyl)-1-leucine N-hydroxysuccinimide ester (1) Following the reaction in an analogous manner to Reference Example 2(1) and using 2-(6-methylpyridin-2-yl)ethanol in place of (S)-3-hydroxytetrahydrofuran, there was obtained N-succinimidyl 2-(6-methylpyridin-2-yl)ethylcarbonate as a brown oil. (2) Following the reaction in an analogous manner to Reference Example 2(2) and using N-succinimidyl 2-(6-methylpyridin-2-yl)ethylcarbonate in place of N-succinimidyl (3S)-3-tetrahydrofuranyl carbonate, there was obtained N-((2-(6-methylpyridin-2-yl)ethyloxy)carbonyl)-1- leucine ethyl ester as a colorless oil. (3) Following the reaction in an analogous manner to Reference Example 2(3) and using N- ((2-(6-methylpyridin-2- yl)ethylbxy)carbonyl)-1-leucine ethyl ester in place of N- (((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine ethyl ester, there was obtained N-((2-(6-methylpyridin-2- yl)ethyloxy)carbonyl)-1-leucine as a colorless oil. (4) Following the reaction in an analogous manner to Reference Example 1(2) and using N-((2-(6-methylpyridin-2-yl)ethyloxy)carbonyl)-1-leucine in place of N-((2-methoxyethoxy)carbonyl)-1-leucine, there was obtained the title compound as a colorless oil. 1H-NMR (300 MHz, DMSO-d6) δ 0.83-0.92 (m, 6H) , 1.49-1.77 (m, 3H), 2.43 (s, 3H) , 2.81 (s, 4H) , 2.99 (t, 2H, J = 6.5), 4.29-4.42 (m, 3H), 7.07-7.09 (m, 2H) . 7.58 (t, 1H, J = 7.7), 7.91 (d, 1H, J = 8.4) . Reference Example 22 N-((2-(5-Ethylpyridin-2-yl)ethyloxy)carbonyl)-1-leucine N-hydroxysuccinimide ester (1) Following the reaction in an analogous manner to Reference Example 2(1) and using (5-ethylpyridin-2-yl)ethanol in place of (S)-3-hydroxytetrahydrofuran, there was obtained N-succinimidyl 2-(5-ethylpyridin-2-yl)ethylcarbonate as a brown oil. (2) Following the reaction in an analogous manner to Reference Example 2(2) and using N-succinimidyl 2-(5-ethylpyridin-2-yl)ethylcarbonate in place of N-succinimidyl (3S)-3-tetrahydrofuranyl carbonate, there was obtained N-((2-(5-ethylpyridin-2-yl)ethyloxy)carbonyl)-1- leucine ethyl ester as a colorless oil. (3) Following the reaction in an analogous manner to Reference Example 2(3) and using N-(((2-(5-ethylpyridin-2-yl)ethyloxy)carbonyl)-1-leucine ethyl ester in place of N-(((3S)-tetrahydrofuran-3- yloxy)carbonyl)-1-leucine ethyl ester, there was obtained N-((2-(5-ethylpyridin-2-yl)ethyloxy)carbonyl)-1-leucine as a colorless oil. (4) Following the reaction in an analogous manner to Reference Example 1(2) and using N- ((2-(5-ethylpyridin-2- yl)ethyloxy)carbonyl)-1-leucine in place of N-((2- methoxyethoxy)carbonyl)-1-leucine, there was obtained the title compound, as a colorless oil. 1H-NMR (300 MHz, DMSO-d6) δ 0.75-0.92 (m, 6H) , 1.12-1.25 (m, 3H), 1.36-1.72 (m, 3H), 2.54-2.63 (m, 2H), 2.81-2.83 (m, 4H) , 2.96-3.02 (m, 2H), 4.04 (m, 1H), 4.29-4.37 (m, 2H) , 7.21 (d, 1H, J = 7.8), 7.53 (m, 1H) , 7.90 (d, 1H, J = 7.8) , 8.34 (m, 1H) . Reference Example 23 N-((2-tert-Butoxyethyloxy)carbonyl)-1-leucine N-hydroxysuccinimide ester (1) Following the reaction in an analogous manner to Reference Example 2(1) and using ethylene glycol tert-butyl ether in place of (S)-3-hydroxytetrahydrofuran, there was obtained N-succinimidyl 2-tert-butoxyethyl carbonate as a colorless oil. (2) Following the reaction in an analogous manner to Reference Example 2(2) and using N-succinimidyl 2-tert-butoxyethyl carbonate in place of N-succinimidyl (3S)-3-tetrahydrofuranyl carbonate, there was obtained N-((2-tert-butoxyethyloxy)carbonyl)-1-leucine ethyl ester as a colorless oil. (3) Following the reaction in an analogous manner to Reference Example 2(3) and using N-((2-tert- butoxye thyloxy) carbonyl)-1-leucine ethyl ester in place of N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine ethyl ester, there was obtained N-((2-tert- butoxye thyloxy) carbonyl) -1-leucine as a colorless oil. (4) Following the reaction in an analogous manner to Reference Example 1(2) and using N-((2-tert-butoxyethyloxy) carbonyl) -1-leucine in place of N-((2-methoxyethyloxy)carbonyl)-1-leucine, there was obtained the title compound as a colorless oil. 1H-NMR(300 MHz, DMSO-d6) δ 0.89 (d, 3H, J = 6.3), 0.92 (d, 3H, J = 6.3), 1.13 (s, 9H), 1.61 (m, 1H), 1.74 (m, 2H), 2.81 (s, 4H), 3.48 (t, 2H, J = 4.7), 4.04 (m, 2H), 4.40 (m, 1H), 8.00 (d, 1H, J = 7.8). Reference Example 24 N-((2-Isopropoxyethyloxy)carbonyl)-1-leucine N-hydroxysuccinimide ester (1) Following the reaction in an analogous manner to Reference Example 2(1) and using ethylene glycol isopropyl ether in place of (S)-3-hydroxytetrahydrofuran, there was obtained N-succinimidyl 2-isopropoxyethyl carbonate as a colorless oil. (2) Following the reaction in an analogous manner to Reference Example 2(2) and using N-succinimidyl 2-isopropoxyethyl carbonate in place of N-succinimidyl (3S)-3-tetrahydrofuranyl carbonate, there was obtained N-((2-isopropoxyethyloxy) carbonyl)-1-leucine ethyl ester as a colorless oil. (3) Following the reaction in an analogous manner to Reference Example 2(3) and using N-((2-isopropoxyethyloxy)carbonyl)-1-leucine ethyl ester in place of N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl)- L-leucine ethyl ester, there was obtained N-((2-isopropoxyethyloxy)carbonyl)-1-leucine as a colorless oil. (4) Following the reaction in an analogous manner to Reference Example 1(2) and using N-{{2- isopropoxyethyloxy)carbonyl)-1-leucine in place of N-{{2- methoxyethyloxy)carbonyl)-1-leucine, there was obtained the title compound as a colorless oil. 1H-NMR (300 MHz, DMSO-d6) δ 0.89 (d, 3H, J = 6.6) , 0.92 (d, 3H, J = 6.3), 1.08 (d, 6H, J = 6.3), 1.61 (m, 1H), 1.74 (m, 2H), 2.81 (s, 4H), 3.53 (m, 2H), 3.57 (m, 1H), 4.07 (m, 2H), 4.40 (m, 1H), 8.02 (d, 1H, J = 7.8). Example 1 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3- (ethylamino)propyl)amino)carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 1) To a solution of the compound of Reference Example 1(1.2 g, 3.6 mmol) and the compound of Reference Example 8 (1.0 g, 4.0 mmol) in DMF was added triethylamine (1.1 g, 11 mmol, 1.5 mL) . The mixture was stirred at room temperature for 18 hours, and concentrated in vacuo. The residue was dissolved in ethyl acetate (EtOAc), and the solution was washed with 1M HCl, saturated aqueous NaHCO3 and saturated aqueous NaCl, dried over anhydrous MgSO4, and concentrated in vacuo. The resulting white solid was washed with a mixture of EtOAc and hexane (1 : 9) to give ((1S) -1- ((( (1S) -1-benzyl-3-ethylamino-2-hydroxy- 3-oxopropyl)amino)carbonyl) -3-methylbutyl)carbamic acid. 2-methoxyethyl ester (0.75 g, 47%) as a white solid. To a solution of ((1S)-1-((((1S)-1-benzyl-3-ethylamino- 2-hydroxy-3-oxo-propyl)amino)carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester (0.7 g, 1.6 mmol) in CH2Cl2 (70 mL) was added Dess-Martin periodinane (1.0 g, 2.4 mmol) . The mixture was stirred at room temperature for 18 hours. Aqueous 10% Na2S203 (35 mL) and saturated aqueous NaHCO3 (35 mL) were added thereto, and the mixture was stirrer at room temperature for 30 minutes. The organic layer was separated, washed with 1M HCl, saturated aqueous NaHCO3 and saturated aqueous NaCl, dried over MgSO4, and concentrated in vacuo. The residue was crystallized from EtOAc/hexane to give the title compound (0.62 g, 88%) as colorless crystals. M.p. 138.0-138.3°C. 1H-NMR(300 MHz, DMSO-d6) δ 0 . 83(d,3H,J=7.5),0.85(d,3H,J=7.2) 1.04(t,3H,J=7.1),1.35(m,2H),1.56(m,1H),2.82(m,1H),3.14(m, 3H),3.25(s,3H),3.47(t,2H,J=4.5),4.04(m,3H),5.19(m,1H), 7.16-7.33(m,6H),8.24(d,1H,J=7.2),8.70(m,1H). MALDI-TOF-MS calcd for C22H33N3O6 (M+Na) + , 458.2267, Fount 458.2361. Example 2 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3- (ethylamino)propyl)amino)carbonyl)-3-methylbutyl)carbamic acid (3S)-tetrahydrofuran-3-yl ester (Compound 2) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 2 in place of the compound of Reference Example 1, there was obtained the title compound as colorless crystals, via ((1S)-1-((((1S)-1- benzyl- 3 -ethylamiino—2 -hydroxy- 3 -oxopropyl) amino) carbonyl) - 3-methylbutyl)carbamic acid (3S)-tetrahydrofuran-3-yl ester. M.p. 158.9-160.7°C 1H-NMR(300MHz,DMSO-d6) δ 0.83(d,3H,J=6.6),0.85(d,3H,J=6.9), 1.04(t,3H,J=7.1),1.35(m,2H),1.55(m,1H),1.83(m,1H),2.08(m, 1H),2.82(m,1H),3.14(m,3H),3.61-3.78(m,4H),4.01(m,1H),5.07 (m,1H),5.19(m,1H),7.17-7.33(m,6H),8.22(d,1H,J=7.2),8.69(t, 1H,J=5.7). MALDI-TOF-MS:C23H33N3O6(M+H)+ , 448.2447, Found: 448 .2509 . Example 3 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3- (ethylamino) propyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid tetrahydro-4H-pyran-4-yl ester (Compound 3) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 3 in place of the compound of Reference Example 1, there was obtained the title compound as colorless crystals, via ((1S)-1-((((1S)-1- benzyl- 3 -ethylamino - 2 -hydroxy- 3 -oxopropyl) amino) carbonyl) - 3-methylbutyl)carbamic acid tetrahydro-4H-pyran-4-yl ester. M.p. 140.0-141.8°C 1H-NMR(300MHz,DMSO-d6) δ 0.84(m,6H),1.04(t,3H,J=7.2),1.35 (m, 2H),1.49(m,3H),1.79(m,2H),2.82 (m,1H),3.14(m,3H),3.41(m,2H), 3.78(m,2H),4.02(m,1H) ,4.66(m,1H),5.19(m,1H),7.15-7.33(m, 6H),8.22(d,1H,J=7.2), 8.69(t,1H,J=5.7). MALDI-TOF-MS:C24H35N3O6(M+Na)+ , 484.2424, Found: 484.2486. Example 4 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3- (cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 4) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 9 in place of the compound of Reference Example 8, there was obtained the title compound as colorless crystals, via ( (1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy- 3-oxo-propyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-methoxyethyl ester. M.p. 112.4-113.5°C 1H-NMR(300MHz,DMSO-d6) δ 0 . 58(m, 2H) , 0 . 65 (m, 2H) , 0 . 83 (d, 3H, J=6.6),0.85(d,3H,3=6.6),1.35(m,2H),1.56(m,1H),2.68-2.88 (m,2H),3.11(m,1H),3.25(s,3H),3.47(t,2H,J=4.5),4.04(m,3H), 5.l7(m,1H),7.17-7.34(m,6H),8.25(dr1H,J=7.2),8.73(d,1H, J=4.8). MALDI-TOF-MS:C23H33N306(M+Na) + , 470 . 2267 , Found: 470 . 2441. [α]D25+6.3° (c0.20,DMSO) Example 5 ((1S)-1-((((1S)-1-Benzyl-3-(cyclopropylamino)-2,3-dioxo- propyl)amino)carbonyl)-3-methylbutyl)carbamic acid (3S)- tetrahydrofuran-3-yl ester (Compound 5) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 2 in place of the compound of Reference Example 1, and the compound of Reference Example 9 in place of the compound of Reference Example 8, there was obtained the title compound as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy-3- oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid (3S)-tetrahydrofuran-3-yl ester. M.p. 169.2-170.5°C 1H-NMR(300MHz,DMSO-d6) δ 0.58(m,2H),0.65(m,2H),0.83(d,3H, J=8.1),0.85(d,3H,J=6.9),1.34(m,2H),1.55(m,1H),1.83(m,1H), 2.08(m,1H),2.79(m,2H),3.12(m,1H),3.61-3.80(m,4H),4.02 (m, 1H),5.08(m,1H),5.17(m,1H),7.22-7.35(m,6H),8.24(d,1H,J=6.6), 8.74(d,1H,J=5.1). MALDI-TOF-MS:C24H33N3O6(M+Na)+, 482.2267, Found: 482.2586. Example 6 ((1S)-1-((((1S)-1-Benzyl-3-cyclopropylamino-2,3- dioxo-propyl)amino)carbonyl)-3-methylbutyl)carbamic acid tetrahydro-4H-pyran-4-yl ester (Compound 6) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 3 in place of the compound of Reference Example 1, and the compound of Reference Example 9 in place of the compound of Reference Example 8, there was obtained the title compound as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy-3- oxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid tetrahydro-4H-pyran-4-yl ester. M.p. 137.0-138.2°C 1H-NMRt 300MHz, DMSO-d6) 6 0 . 58 (m, 2H) , 0 . 65 (m, 2H) , 0 . 84(m, 6H) . 1.35(ra 2H) ,1.48(m,3H),1.80(m,2H),2.79(m,2H),3.11(m,1H),3.41 (m,2H),3.79(m,2H),4.03(m,1H),4.65(m,1H),5.18(m,1H),7.15- 7.30(m,6H) ,8.23(d,1H,J=6.9),8.73(d,1H,J=5.4). MALDI-TOF-MS:C25H35N306(M+H)+ , 474.2604, Found: 474.2643. Example 7 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3- ( propylamino) propyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid 2-methoxyethyl ester (Compound 7) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 10 in place of the compound of Reference Example 8, there was obtained the title compound as colorless crystals, via ((1S)-1-((((1S)- 1-benzyl-2-hydroxy-3-oxo-3- (propylamino)propyl) amino)carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester. M.p.l08.8-109.9°C 1H-NMR(30 MHz,DMS0-d6) δ 0.83(m,9H),1.35(m,2H),1.46(m,2H), 1.55(m,1H),2.83(dd,1H,J=14.0,9.2),3.08(m,3H),3.25(s,3H), 3.48(t,2H,J=4.4),4.04(m,3H),5.19(m,1H),7.22-7.28(m,6H), 8.24(d,1H,J=6.9),8.68(t,1H,J=5.6). MALDI-TOF-MS:C23H35N3O6(M+H) + , 450.2604, Found: 450.2832. Example 8 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3- (cyclobutylamino) propyl) amino) carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 8) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 11 in place of the compound of Reference Example 8, there was obtained the title compound as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-3-cyclobutylamino-2-hydroxy-3- oxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid 2-methoxyethyl ester. M.p. 114.2-115.3°C 1H-NMR(300MHz,DMSO-d6) δ 0.84(m, 6H),1.34(m,2H),1.49-1.72(m, 3H),2.10(m,4H),2.81(dd,1H,J=13.8,9.3),3.10(m,1H),3.25(s, 3H),3.47(m,2H),4.03(m,3H),4.22(m,1H),5.15(m,1H),7.24(m,6H), 8.24(d,1H,J=7.2),8.91(d,1H,J=7.8). MALDI-TOF-MS:C24H35N3O6(M+Na)+ , 484.2424, Found: 484.2400. Example 9 ((1S)-1-((((1S)-1-Benzyl-3-butylamino-2,3-dioxo- propyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 9) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 12 in place of the compound of Reference Example 8, there was obtained the title compound as colorless crystals, via ((1S)-1-((((1S)- 1-benzyl-3-butylamino-2 -hydroxy- 3 -oxopropyl) amino) carbonyl) -3-methylbutyl)carbamic acid 2-methoxyethyl ester. M.p. 94.0-95.2°C 1H-NMR(300MHz,DMSO-d6) δ 0.85(m,9H),1.25(m,2H),1.35(m,2H), 1.42(m,2H),1.56(m,1H),2.83(dd,1H,J=13.8,9.0),3.10(m,3H), 3.25(s,3H),3.47(t,2H,J=4.5),4.04(m,3H),5.l8(m,1H),7.21- 7.29(m,6H),8.23(d,1H,J=6.6),8.67(t,1H,J=6.0). MALDI-TOF-MS:C24H37N3O6(M+H)+ , 464.2760, Found: 464 . 2870 . Example 10 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-(2,2,2- trifluoroethylamino)propyl)amino)carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 10) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 13 in place of the compound of Reference Example 8, there was obtained the title compound as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-2-hydroxy-3-oxo-3-(2,2,2- trifluoroethyl-amino)propyl)amino)carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester. M.p. 152.5-153.9°C 1H-NMR(300MHz, DMSO-d6) δ 0.84(m,6H),1.34(m,2H),1.55(m,1H), 2.86(dd,1H,J=14.0,8.6),3.10(dd,1H,J=14.1,4.8),3.25(s,3H), 3.48(t,2H,J=4.7),3.90(m,2H),4.04(m,3H),5.14(m,1H),7.21- 7.31(m,6H),8.34(d,1H,J=6.9),9.29(m,1H). MALDI-TOF-MS:C22H3oF3N3O6(M+H)+ , 490.2165, Found: 490.2434. Example 11 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-(2- indanylamino)propyl)amino)carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 11) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 14 in place of the compound of Reference Example 8, there was obtained the title compound as colorless crystals, via ((1S)-1-((((1S)- 1-benzyl-2-hydroxy-3-(2-indanylamino)-3- oxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid 2-methoxyethyl ester. M.p. 141.9-143.5°C 1H-NMR(300MHz,DMSO-d6) δ 0.83(d,3H,J=6.9),0.86(d,3H,J=6.9), 1.36(m,2H),1.57(m,1H),2.80-2.96(m,3H),3.10-3.18(m,3H),3.24 (s,3H),3.47(t,2H,J=4.7),4.04(m,3H),4.50(m,1H),5.19(m,1H), 7.13-7.30(m,10H),8.29(d,1H,J=6.9),8.97(d,1H,J=7.2). MALDI-TOF-MS:C29H37N3O6(M+H) + , 524.2760, Found: 524.2810.0 Example 12 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-(2- methoxyethylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 12) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 15 in place of the compound of Reference Example 8, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-1-benzyl- 2-hydroxy-3- (2-methoxyethylamino) -3-oxopropyl)amino)carbonyl) -3-methylbutyl)carbamic acid 2-methoxyethyl ester M.p. 127.0-127.9°C 1H-NMR(300MHz,DMSO-d6) δ 0.83(d,3H,J=6.9),0.86(d,3.J=6.9), 1.35(m,2H),1.56(m,1H),2.83(dd,1H,J=13.8,9.0),3.11(dd,1H,J=l 4.0,4.4),3.24(s,3H),3.25(s,3H),3.16-3.34(m,2H),3.39(m, 2H),3 .48(t,2H,J=4.5),4.04(m,3H),5.20(m,1H),7.18-7.30(m,6H),8.21( d,1H,J=6.9),8.66(t,1H,J=5.4). MALDI-TOF-MS :C23H35N3O7(M+Na) + , 488 . 2373 , Found: 488 . 2680 . Example 13 ((1S)-1-((((1S)-2,3-Dioxo-3-ethylamino-1- (phenylethyl)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 13) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 16 in place of the compound of Reference Example 8, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-3- ethylamino-2-hydroxy-3-oxo-1- (phenylethyl)propyl)amino)carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester. M.p. 119.1-120.4°C 1H-NMR( 300MHz,DMSO-d6) δ 0.89(t,6H,J=6.3),1.03(t,3H,J=7.2) , 1.43(t,2H,J=7.2).1.61-1.85(m,2H),2.07(m,1H),2.56-2.74 (m,2H),3.07-3.17(m,2H),3.25(s,3H),3.49(t,2H,J=4.7),4.05- 4.14(m,3H),4.89(m,1H),7.16-7.36(m,5H),7.34(d,1H,J=8.4), 8.33(d,1H,J=6.9),8.65(t,1H,J=5.9). MALDI-TOF-MS:C23H35N3O6(M+H)+, 450 . 2604 ,Found: 450. 2701. Example 14 ((1S)-1-((((1S)-2,3-Dioxo-3-ethylamino-1- (phenylethyl)propyl)amino)carbonyl)-3- methylbutyl) carbamic acid (3S)-tetrahydrofuran-3-yl ester (Compound 14) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 2 and 16 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-3-ethylamino-2-hydroxy-3-oxo-1- (phenylethyl)propyl)amino)carbonyl)-3-methylbutyl)carbamic acid (3S)-tetrahydrofuran-3-yl ester. M.p. 111.9-114.5°C 1H-NMR(300MHz,DMSO-d6) δ 0 . 89 (t, 6H , J=6 . 3) , 1. 03 (t, 3H, J=7.2), 1.43(t,2H,J=7.4),1.60-1.91(m,3H),2.09(m,2H),2.56-2.76(m, 2H),3.07-3.17(m,2H),3.63-3.82(m,4H),4.02-4.13(m,1H),4.88 (m,1H), 5.09-5.13(m,1H),7.16-7.31(m,5H),7.34(d,1H,J=8.4),8.3 4(d,1H,J=6.9),8.66(t,1H,J=5.7). MALDI-TOF-MS:C24H35N3O6(M+H) + , 462. 2604,Found: 462. 2870. Example 15 ((1S)-1-((((1S)-2,3-Dioxo-3-cyclopropylamino-1- (phenylethyl) propyl) amino) carbonyl) - 3 -methylbutyl} carbamic acid 2-methoxyethyl ester (Compound 15) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Example 17 in place of the compound of Reference Example 8, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-3- cyclopropylamino-2-hydroxy-3-oxo-1- (phenylethyl)propyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-methoxyethyl ester M.p. 109.7-111.1°C 1H-NMR(300MHz,DMSO-d6) δ 0.53-0.68(m, 4H),0.87-0.91(m,6H), 1.43(t,3H,J=7.2),1.59-1.85(m,2H),2.01-2.13(m,1H),2.56-2.74 (m,3H),3.25(s,3H),3.48-3.51(m,2H),4.05-4.14(m,3H),4.87(m,lH ),7.17-7.36(m,6H),8.34(d,1H,J=6.6),8.69(d,1H,J=5.1). MALDI-TOF-MS:C24H35N3O6(M+H)+ , 462. 2604, Found :462.2742. Example 16 ((1S)-1-((((1S)-2,3-Dioxo-3-cyclopropylamino-1- (phenylethyl)propyl)amino)carbonyl) - 3 - methylbutyl)carbamic acid (3S)-tetrahydro-furan-3-yl ester (Compound 16) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 2 and 17 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-3-cyclopropylamino-2-hydroxy- 3-oxo-1-(phenylethyl)propyl)amino)carbonyl) - 3 - methylbutyl)carbamic acid (3S)-tetrahydrofuran-3-yl ester. M.p. 115.8-116.2°C 1H-NMR(300MHzDMSO-d6) δ 0.56-0.59(m,4H),0.88(t,6H,J=6.3), 1.42(t,2H,J=7.4),1.60-1.91(m,3H),2.09(m,2H),2.56-2.76(m, 3H),3.63-3.81(m,4H),4.05-4.13(m,1H),4.87(m,1H),5.09-5.13(m, 1H),7.20-7.35(m,6H),8.34(d,1H,J=6.9),8.69(d,1H,J=5.1). MALDI-TOF-MS:C25H35N3O6(M+H) + , 474. 2604,Found: 474 . 2598 . Example 17 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3- (cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 5-methoxy-3-oxapentyl ester (Compound 17) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 4 and 9 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy-3- oxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid 5-methoxy-3-oxapentyl ester. M.p. 127.9-128.7°C 1H-NMR(300MHzDMSO-d6) δ 0 . 54-0 . 66 (m, 4H) , 0 . 81-0 . 86 (m, 6H) , 1.30-1-42(m,2H),1.57(m, 1H),2.73(m,1H),2.82(dd,1H,J=14.3, 9.2),3.11(dd,1H,J=13.8,4.2),3.24(s,3H),3.42-3.44(m,2H), 3.50-3.57(m,4H),3.99-4.04(m,3H),5.17(m,1H),7.22-7.30(m,6H) , 8.22(d,1H,J=6.9),8.71(d,1H,J=4.8). MALDI-TOF-MS :C25H37N3O7(M+Na) + , 514 . 2530 .Found: 514 . 2944 . [α]D25+13.9° (c 0.20,DMSO) Example 18 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3- (cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 8-methoxy-3,6-dioxaoctyl ester (Compound 18) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 5 and 9 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy-3- oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 8-methoxy-3,6-dioxaoctyl ester. M.p. 116.0-117.2°C. 1H-NMR(300MHz,DMSO-d6) δ 0 . 58 (m, 2H) , 0 . 65 (m, 2H) , 0 . 83 (d, 3H, J=7.8),0.85(d,3H,J=6.9),1.35(m,2H),1.57(m,1H),2.73-2.86 (m,2H) ,3.11(m,1H),3.24(s,3H),3.44(m,2H),3.51(m,6H),3.56(t,2 H, J=4.7),4.04(m,3H),5.17(m,1H),7.22-7.31(m,6H),8.25(d,1H,J= 6.9),8.73(d,1H,J=5.1). MALDI-TOF-MS:C27H4iN3O8(M+Na) +, 558 . 2792 ,Found: 558 .2111. [α]D25+2.5° (c 0.20.DMSO) Example 19 ((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3- (cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 111-methoxy-3 , 6 , 9-trioxaundecanyl ester (Compound 19) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 6 and 9 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy-3- oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 111-methoxy-3,6,9-trioxaundecanyl ester. M.p. 97.5-98.5°C 1H-NMR(300MHz,DMSO-d6) δ 0.54-0.66(m,4H),0.81-0.86(m,6H), 1.32-1.37(m,2H),1.56(m,1H),2.73(m,1H),2.82(dd,1H,J=14.0,9.2 ),3.11(dd,1H,J=14.1,4.2),3.24(s,3H),3.41-3.44(m.2H),3.50-3. 51(m,10H),3.54-3.57(m,2H),3.99-4.08(m,3H),5.16(m,1H),7.22-7 .31(m,6H),8.25(d,1H,J=7.2),8.73(d,1H,J=5.1). MALDI-TOF-MS :C29H45N3O9(M+Na) + , 602 . 3054 .Found: 602 . 3427 . [α]D25+6.9° (c 0.20,DMSO) Example 20 ((1S)-1-((((lS}-1-Benzyl-2,3-dioxo-3- (cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 14-methoxy-3,6,9,12-tetraoxa- tetradecanyl ester (Compound 20) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 7 and 9 in place of the compounds of Reference Examples 1 and 7 respectively, the title compound was obtained as colorless crystals, via ( (IS) -1- ( ( ( (,lS)-1-benzyl-3-cyclopropylamino-2-hydroxy-3- oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 14-methoxy-3,6,9,12-tetraoxatetradecanyl ester. M.p. 98.5-99.9°C 1H-NMR(300MHz,DMSO-d6) δ 0.58(m,2H),0.65(m,2H),0.83 (d,3H, J=6.9),0.85(d,3H,J=7.8),1.35(m,2H),1.57(m,1H),2.73-2.86 (m,2H),3.11(m,1H),3.24(s,3H),3.42(m,2H),3.51(m,14H),3.56 (t.2H,J=3.3),4.04(m,3H),5.17(m,1H),7.22-7.30(m,6H),8.24( d, 1 H,J=6.9),8.72(d,1H,J=4.5). MALDI-TOF-MS:C31H49N3O10(M+Na)+ , 646 . 3316 ,Found: 646 . 3404 . Example 21 ((1S)-1-((((1S)-2,3-Dioxo-1-(2-methylpropyl)-3-(2- phenoxyethyl)aminopropyl)amino)carbonyl)-3- methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 21) Following the reaction in an analogous manner to Example 1 and using the compound of Reference Examples 18 in place of the compound of Reference Example 8, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-2- hydroxy-1- ( 2-methylpropyl) -3-oxo-3- (2- phenoxyethyl) aminopropyl) amino) carbonyl) - 3 - methylbutyl)carbamic acid 2-methoxyethyl ester. M.p. 99.7-100.5°C 1H-NMR(300MHz,DMS0-d6) δ 0.88(dd,12H,J=12.0,6.3),1.35-1.54 (m,4H),1.58-1.75(m,2H),3.25(s,3H),3.46-3.53 (m, 4H) ,4.03-4.07 (m,5H),5.06(m,1H),6.91-6.95(m,3H),7.26-7.31(m,3H),8.15(d,lH ,J=7.2),8.81(t,1H,J=5.9). MALDI-TOF-MS :C25H39N3O7(M+H)+ , 494 . 2866 , Found: 494 . 2967 . Example 22 ((1S)-1-("( ((1S)-2,3-Dioxo-1-(2-methylpropyl)-3-(2- phenoxyethyl)aminopropyl)amino)carbonyl)-3- methylbutyl)carbamic acid 5-methoxy-3-oxapentyl ester (Compound 22) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 4 and 18 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ((1S)-!-((((1S)-2-hydroxy-1-(2-methylpropyl)-3-oxo-3-(2- phenoxyethyl)aminopropyl)amino)carbonyl) - 3 - methylbutyl)carbamic acid 5-methoxy-3-oxapentyl ester. M.p. 53.5-54.1°C 1H-NMR(300MHz,DMSO-d6) δ 0.87(dd,12H,J=12.2,6.5),1.35-1.54 (m,4H),1.58-1.75(m,2H),3.24(s,3H),3.41-3.45(m,2H),3.47-3.57 (m,6H),4.03-4.07(m,5H),5.06(m,1H),6.91-6.96(m,3H),7.26-7.31 (m,3H),8.17(d,1H,J=6.9),8.83(t,1H,J=5.7). MALDI-TOF-MS :C27H43N3O8(M+H) + , 538 . 3128 , Found: 538 . 3140 . Example 23 ((1S)-1-((((lRS)-3-amino-1-benzyl-2,3- dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 5-methoxy-3-oxapentyl ester (Compound 23) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 4 and 19 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ((1S)-1-((((lRS)-3-amino-1-benzyl-2-hydroxy-3-oxo- propyl)amino)carbonyl)-3-methylbutyl)carbamic acid 5- methoxy-3-oxapentyl ester. 1H-NMR(300MHz,DMSO-d6) δ0 . 77(d,3H,J=6.3),0.83(d,1.5H,J=6.6), 0.86(d,1.5H,J=6.9),1.05-1.63(m,3H),2.68-2.85(m,1H),3.12(m,l H),3.23(s,3H),3.42(m,2H),3.51-3.56(m,4H),4.03(m,3H),5.22(m, 1H),7.21-7.31(m,6H),7.81(d,1H,J=14),8.06(d,1H,J=18),8.19(d, 0.5H,J=6.9),8.26(d,0.5H,J=7.5). Example 24 ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3-dioxo- propyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-(pyridin-2-yl)ethyl ester (Compound 24) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 20 and 9 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2-hydroxy-3- oxopropyl)amino)carbonyl)-3-methylbutyl}carbamic acid 2-(pyridin-2-yl)ethyl ester. 1H-NMR(300MHz,DMSO-d6) δ 0.58-0.66(m,4H),0.83(t,6H,J=7.1), 1.31-1.35(m,2H),1.53(m,1H),2.74(m,1H).2.81(dd,1H,J=14.1,9.3 ),3.02(t,2H,J=6.3),3.11(dd,1H,J=14.0,4.1),4.01(m,1H),4.28-4 .32(m,2H),5.17(m,1H),7.14-7.34(m,8H),7.75(t,1H,J=6.8),8.23{ d,1H,J= 7.2),8.51(d,1H,J=4.2),8.71(d,1H,J=4.5). Example 25 ( (1S)-1-((((1S)-1-Benzyl-3-(cyclopropylamino)-2,3- dioxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid 2-(6-methylpyridin-2-yl)ethyl ester (Compound 25) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 21 and 9 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ( ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2-hydroxy-3- oxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid 2-(6-methylpyridin-2-yl)ethyl ester. M.p. 162.0-163.6°C 1H-NMR (300 MHz, DMSO-d6) δ 0.54-0.66 (m, 4H) , 0.76-0.86' (m, 6H), 1.54 (m, 1H), 2.43 (s, 3H), 2.73-2.86 (m, 2H), 2.96 (t, 2H, J = 6.5), 3.11 (m, 1H), 4.03 (m, 1H), 4.21-4.34 (m, 2H), 5.17 (m, 1H), 7.07-7.30 (m, 8H), 7.58 (t, 1H, J = 7.7), 8.23 (d, 1H, J = 6.9), 8.72 (d, 1H, J = 4.8). Example 26 ((1S)-1-((((1S)-1-Benzyl-3-(cyclopropylamino)-2,3- dioxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid 2-(5-ethylpyridin-2-yl)ethyl ester (Compound 26) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 22 and 9 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2-hydroxy-3-o xopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-(5-ethylpyridin-2-yl)ethyl ester. M.p. 119. 9-121. 0°C 1H-NMR (300 MHz, DMS0-d6) δ 0.58-0.66 (m, 4H) , 0.75-0.85 (m, 6H) , 1.17 (t, 3H, J = 7.7), 1.33-1.36 (m, 2H), 1.53 (m, 1H), 2.58 (dd, 2H, J = 15.5, 8.3), 2.74-2.85 (m, 2H) , 2.94-2.98 (m, 2H) , 3.12 (m, 1H), 4.04 (m, 1H), 4.28-4.29 (m, 2H), 5.17 (m, 1H), 7.13-7.26 (m, 7H), 7.55 (d, 1H, J = 8.1), 8.22-8.35 (m, 2H) , 8.75 (m, 1H). Example 27 ((1S)-1-((((1S)-1-Benzyl-3-(cyclopropylamino)-2,3- dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-tert-butoxyethyl ester (Compound 27) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 23 and 9 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2-hydroxy-3- oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-tert-butoxyethyl ester. 1H-NMR (300 MHz, DMSO-d6) δ 0.58 (m, 2H) , 0.65 (m, 2H) , 0.83 (d, 3H, J = 7.5), 0.85 (d, 3H, J = 6.9), 1.12 (s, 9H) , 1.35 (m, 2H), 1.57 (m, 1H), 2.74 (m, 1H), 2.82 (m, 1H), 3.11 (m, 1H) , 3.45 (m, 2H), 3.98 (m, 3H), 5.17 (m, 1H), 7.24 (m, 6H), 8.23 (d, 1H, J = 6.6), 8.71 (d, 1H, J = 4.8). Example 28 ((1S)-1-((((1S)-1-Benzyl-3-(cyclopropylamino)-2,3- dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-isopropoxyethyloxyl ester (Compound 28) Following the reaction in an analogous manner to Example 1 and using the compounds of Reference Examples 24 and 9 in place of the compounds of Reference Examples 1 and 8 respectively, the title compound was obtained as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2-hydroxy-3- oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid 2-isopropoxyethyl ester. 1H-NMR (300 MHz, DMSO-d6) δ 0.58 (m, 2H) , 0.65 (m, 2H) , 0.83 (d, 3H, J = 7.2), 0.85 (d, 3H, J = 6.9), 1.07 (d, 6H, J = 5.7), 1.35 (m, 2H), 1.57 (m, 1H) , 2.74 (in, 1H) , 2.82 (m, 1H) , 3.12 (m, 1H) , 3.50 (m, 2H) , 3.55 (m, 1H) , 4.01 (m, 3H) , 5.17 (m, 1H) , 7.24 (m, 6H), 8.22 (d, 1H, J = 6.9), 8.71 (d, 1H, J = 3.6). Test Example 1 (1) Measurement of inhibitory activity against µ-calpain and m-calpain The inhibitory activity against [X-calpain and m-calpain was assayed according to the method described in Anal. Biochem. 1993, vol. 208, p. 387-392. That is, to 2.5 µL of a DMSO solution containing a varying concentration of the test sample in a 96-well plate was added 200 µL of a reaction solution containing 0.5 mg/mL casein, 50mM Tris-HCl buffer (pH 7.4), 20 mM dithiothreitol and 1.0 nmol µ-calpain (derived from human red blood cells; available from Cosmo Bio Co. Ltd.) or m-calpain (derived from porcine kidney; available from Cosmo Bio Co. Ltd. ) . After 20mM aqueous calcium chloride (50 µL) was added thereto, the mixture was incubated at 30°C for 60 minutes. Then, 100 µL of the reaction solution was transferred to another 96-well plate, and purified water (50 µL) and 50% aqueous solution (100 µL) of Protein Assay Dye Reagent (available from Bio-Rad Laboratories, Inc.; catalogue No. 500-600) were added thereto. The reaction mixture was allowed to stand at room temperature for 15 minutes, and its absorbance was measured at 59 5 nm. The absorbance of a reaction mixture prepared in the same manner as mentioned above, except that a DMSO solution contained no sample, was used as a control value, and that of a reaction mixture prepared in the same manner as mentioned above, except that 1 mM aqueous EDTA solution (50 µL) was used in place of 20 mM aqueous calcium chloride, was used as a blank value. Inhibition rate was calculated by means of the following equation, and the concentration required for 50% inhibition (IC50) was determined. Inhibition rate (%)={1-(measured value minus blank value)/ (control value minus blank value)} x 100 The calpain inhibitory activities are shown in Table 1, which indicates that the compounds of the present invention strongly inhibited activities of µ-calpain and m-calpain. Test Example 2: Solubility Solubility of the compounds of the present invention in 10 mM phosphate buffer (pH 7.0) was measured. The solubility of the compounds of the present invention is shown in Table 2. Table 2 Test Example 3: Permeability test with Caco-2 cells 1 x 105/cm2 of Caco-2 cells (Catalog No. HTB-37, available from ATCC, passage number: 56) were seeded into a culture insert (polycarbonate porous filter: FALCON(trade mark) 3096, pore diameter 3 µm; area 0.31 cm2), and incubated for 22 days under the conditions of 37°C and 5% CO2 to prepare a monolayer cell. As a culture medium for the incubation, Dulbecco's modified Eagle's minimum essential medium (GIBCO BRL) supplemented with 10% fetal calf serum (GIBCO BRL), antibiotic-antimycotic mixture, liquid (GIBCO BRL) , non-essential amino acid solution. (GIBCO BRL) and 2 mmol/L L-glutamine (GIBCO BRL) was used. The cells were preincubated in advance in a Hanks' Balanced Salt Solution (apical membrane side: pH 6.5, basolateralt membrane side: pH 7.4) containing no sample or no control substance at 37°C for one hour. A Hanks' Balanced Salt Solution (pH 6.5, 37°C) containing a 10 pm sample or a control substance was run to the apical membrane side (250 µL) , and the sample (950 µL) permeated through the basolateral membrane was quantified. That is , 500 µL was collected from the basolateral membrane side after one or two hours, and the permeation coefficient was measured. Propranolol was used as a positive control, and 14C-mannitol was used as a negative control. LC-MS/MS was used for quantitative analysis of samples, and a liquid scintillation counter was used for quantitative analysis of 14C-mannitol. An amount of the sample or the control substance which had been permeated through the basolateral membrane of Caco-2 monolayer cells was determined, and apparent permeation coefficient (Papp) was calculated according to the formula: PaPP= (δQ/δt) x (1/60AC0). Papp : apparent permeation coefficient (cm/sec) δQ/5t : permeation velocity (pmol/min) A : area of monolayer cell = 0.33 cm2 C0 : initial concentration at apical membrane side (pmol/mL) Test Example 4 : Measurement of partition coefficient using I AM column Analysis by HPLC system was carried out under the conditions given below, and retention time of each substance was measured. Column: IAM fast screening mini-column (Regis Technologies, Inc.) Mobile phase: Dulbecco's phosphate buffer (pH 7.4) Detection wavelength: 250 nm Column temperature: room temperature Injection amount: 5.0 to 20 µL Flow rate: 0.5 mL/min Sample solution: 5 mg of sample was dissolved in 100 µL of acetonitrile, and a mobile phase was added to make 1 mL of a sample solution. The measured value was inserted into the following formula, and the partition coefficient (K'IAM) was calculated, k' IAM = (tR-to)/t0 t0: retention time of the peak derived from acetonitrile tR: retention time of the peak of the sample The membrane permeability of the compounds of the present invention was evaluated on the basis of the partition coefficient (K'IAM) calculated from the permeability through Caco-2 cell membrane (PapP (apical membrane side -> basolateral membrane side)) and/or the correlated retention time in IAM column analysis. The results of Caco-2 cell permeability assay showed that all compounds measured showed Papp = 10-6 or higher, a value indicating that the permeability is not a rate-limiting step in absorption. Also, an IAM column analysis revealed that the compound tested showed k' IAM = 0.7 or higher, which was considered to be equivalent to Caco-2 cell permeability of Papp=10-6. According to these results, it was considered that oral administration would not cause any problem on membrane permeability in the digestive tract during absorption. Test Example 5: Measurement of transportation rate into blood The compound of the present invention was administered orally to Macaca fascicularis (crab-eating monkey) at a dose of 10 mg/kg. The blood was collected with the lapse of time, and the concentration of each compound in the plasma was measured. The maximum plasma concentration (Cmax) and the area under the blood concentration-time curve (AUC) were shown in Table 4. When the compound of the present invention was administered orally, it was transported into the blood with a higher enzyme inhibitory activity (IC50) than that shown in Test Example 1, elucidating that the compound of the present invention has excellent pharmakokinetics. Table 4 Experimental Example 6 Effect on rat retinal ischemia reperfusion injury Male SD rats (body weight: 150-200 g, purchased from Charles River Japan, Inc.) were used. For anesthesia, a mixture of equivalent amounts of 50 mg/mL ketamine injection and 20 mg/mL xylazine injection was administered intramuscularly at 1.0 mL/Kg body weight into the femora of the rats 15 minutes before ischemia. To achieve ischemia, the optic nerve including central retinal artery was ligated using a Sugita Clip minitype (No. 98), and the blood flow was blocked for 55 minutes . Such ligation was released 55 minutes after the above ligation, and blood flow was made to run again into retina (hereinafter, referred to as ischemia reperfusion). For normal group, central retinal artery was only exposed and ischemia was not set up. After 7 days from reperfusion in ischemia, a tissue specimen was prepared. For preparation of the tissue specimen, an excess amount of pentobarbital solution was intraperitoneally administered to sacrifice the animal, and eyeball was enucleated. The enucleated eyeball was dipped and fixed for 24 hours in a fixing solution of 2% paraformaldehyde and 2.5% glutaraldehyde (0.1 Mphosphate buffer, pH 7 . 4) . After fixing, a paraffin embedded block of eyeball was prepared, and such a paraffin embedded eyeball was sliced with a microtome in a thickness of 3 µm at the section passing through the center of the optic disc. The sections were stained with hematoxylin and eosin (HE) in a conventional manner. The stained sections were observed under an optical microscope, and ganglion cells of retina per 0.25 mm width of retina section at 1-2 mm from the center of the optic disc were counted. Compound 17 was used as a drug to be tested. A solution obtained by dissolving sodium carboxymethylcellulose in distilled water to a concentration of 0.5% (CMC solution) was orally administered to the control group, and a solution obtained by suspending Compound 17 in a CMC solution at 1.0 %, such that Compound 17 was administered at 100 mg/Kg body weight, was orally administered to the drug group, both at 15 minutes before start of ischemia and immediately after release from ischemia (Compound 17 administration group). A CMC solution was administered to control group and normal group in a similar manner. The results thereof are shown in Fig. 1. The ganglion cell count decreased to about 1/4 of that of the normal group (control group) due to ischemia reperfusion. In contrast. Compound 17 administration (drug group) significantly suppressed the decrease due to ischemia reperfusion in the ganglion cell count. The above results suggest that Compound 17 of the present invention has an effect to improve retinal ischemic disorder. Compound 4, starch and lactose were blended well, and formulated into granules for tableting according to the wet granule tableting method. After addition of magnesium stearate, the granules were compressed to make 400 tablets . The tablets were, if required, coated with an enteric coating agent (methacrylic acid copolymer). The above components were mixed under sterile conditions according to the conventional method to prepare eye drops. Formulation Example 3: Injection Compound 17 100 mg Sodium chloride 900 mg IN Sodium hydroxide q.s. Distilled water for injection total volume 100 mL The above components were mixed under sterile conditions according to the conventional method to prepare an injection preparation. Industrial Applicability Since the compounds of the formula (I) of the present invention have excellent calpain inhibitory activity and good oral absorbability, they are useful as a prophylactic and therapeutic agent for various diseases related to calpain such as ischemic disease, immunologic disease, multiple sclerosis Alzheimer's disease, osteoporosis, diseases caused by brain tissue damage, cataract, glaucoma, retinal disease, retinochoroiditis (diabetic retinopathy, retinal vein occulusion, macular degeneration, retinitis pigmentosa, hypertensive retinopathy, retinal detachment, etc.), posterior eyeball complications due to photocoagulation or a disease involving neovascularization. WE CLAIM: 1. A compound represented by the formula (I) wherein R1 is (1) a group represented by the formula (IIb) in which n is an integer of 2 to 5, (2) a straight or branched C1-6 alkyl substituted by a pyridyl group optionally having a C1-3 alkyl substituent on the pyridine ring, or (3) a tetrahydrofuranyl group or a tetrahydropyranyl group; R2 is a straight or branched C1-6 alkyl, optionally substituted by a phenyl; and R3 is hydrogen, a straight or branched C1-6 alkyl or is selected from the group consisting of cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. 2. The compound as claimed in Claim 1, wherein R1 is a group of the formula (IIb) in which n is an integer of 2 to 5. 3. The compound as claimed in Claim 1, wherein R3 is cyclopropyl. 4. The compound as claimed in claim 1 selected from the group consisting of ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-(cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 5-methoxy-3-oxapentyl ester, ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-(cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 8-methoxy-3,6-dioxaOctyl ester, ((1S)-1 -((((1S)-1 -benzyl-2,3-dioxo-3-(cyclopropylamino)propyl)amino)carbonyl)-3- methylbutyl)carbamic acid 11-methoxy-3,6,9-trioxaundecanyl ester, or ((1 S)-1-((((1S)-1 -benzyl-3-(cyclopropyIamino)-2,3-dioxopropyl)amino)carbonyl)-3 - methylbutyl)carbamic acid 2-(pyridin-2-yl)ethyl ester. 5. A medicament comprising the compound as claimed in Claim 1. 6. The compound as claimed in Claim 1, which is ((1S)-1-((((1S)-1- benzyl-2,3-dioxo-3-(cyclopropylamino)propyl)amino)carbonyl)-3-methylbutyl)carbamic acid 5- methoxy-3-oxapentyl ester. (54) Title: ALPHA-KETOAMIDE DERIVATIVE, AND PRODUCTION METHOD AND USE THEREOF (57) Abstract: The present invention provides a compound represented by the formula (I): (INSERT CHEMICAL FORMULA) (wherein R1 is a lower alkyl substituted by a lower alkoxy or a heterocyclic group, or a heterocyclic group; R2 is a lower alkyl optionally substituted by a phenyl; and R3 is a lower alkyl optionally substituted by a halogen, a lower alkoxy or a phenyl, or a fused polycyclic hydrocarbon group), which is well absorbed orally, exhibits durability of good blood level and has potent calpain inhibitory aclivity.

Full Text

DESCRIPTION
ALPHα-ketoamide DERIVATIVE, AND PRODUCTION METHOD AND USE
THEREOF
Technical Field
The present invention relates to a novel α-ketoamide
derivative having calpain inhibitory activity. Also, the
present invention relates to a medicament comprising the novel
1379/KOLNP/2006
α-ketoamide derivative.
Background Art
Calpain is one of the intracellular proteases
ubiquitously present in a living body, which is activated by
Ca2+. It has been elucidated to this day that abnormal
activation of calpain is involved in various diseases such as
cerebral apoplexy, subarachnoid hemorrhage, Alzheimer's
disease, ischemic disease, muscular dystrophy, cataract,
platelet aggregation disorder, arthritis and the like (see
Non-patent literature 1).
On the other hand, it has been reported that a calpain
inhibitor is effective for maintaining permeability of lens in
an experimental cataract model of cultured lens and is useful
as a therapeutic agent for cataract, etc. (see Non-patent
literature 2, Patent literature 1).
Examples of calpain inhibitors which have been so far
reported are peptide halomethane derivatives, peptide
diazomethane derivatives, peptidyl aldehyde derivatives,
peptidyl α-ketoamide derivatives and the like (for example,

see Patent literatures 2 to 6, Non-patent literatures 3 to 4) .
(Patent literature 1) WO 93/23032
(Patent literature 2) JP-B-29229/1994
(Patent literature 3) EP-A-0771565
(Patent literature 4) U.S. Patent No. 6057290
(Patent literature 5) JP-A-147564/1998
(Patent literature 6) WO 92/12140
(Non-patent literature 1) Trends in Pharmacological
Sciences, vol. 15, page 412, 1994
(Non-patent literature 2) Current Eye Research, vol. 10,
Pages 657 to. 666, 1991
(Non-patent literature 3) The Biochemical Journal, vol.
253, pages 751 to 758, 1988
(Non-patent literature 4) Journal of Medicinal Chemistry,
vol.35, pages 216 to 220, 1992
Disclosure of the Invention
An object of the present invention is to provide a compound
having potent calpain inhibitory activity, which is well
absorbed orally and exhibits durability of good blood level.
The present inventors have conducted intensive studies
to create a calpain inhibitor having tissue transport and
absorbability, especially good oral absorbability and
durability of good blood level. The present inventors designed
α-ketoamide derivatives having an amphiphatic group in the
molecule thereof, and found among those compounds a compound
having calpain protease inhibitory activity and good oral
absorbability. They have conducted further studies and thus
completed the present invention.

Namely, the present invention relates to
(1) A compound represented by the formula (I)

wherein
R1 is a lower alkyl substituted by a lower alkoxy or a
heterocyclic group, or a heterocyclic group;
R2 is a lower alkyl optionally substituted by a phenyl;
and
R3 is hydrogen, a lower alkyl optionally substituted by
a halogen, a lower alkoxy or a phenyl, or a fused polycyclic
hydrocarbon group,
(2) the compound according to the above (1), wherein the
lower alkyl represented by R1 which is substituted by a lower
alkoxy is a group the formula (IIa)

in which R4 is a lower alkyl, R5 is a lower alkylene, and m is
an integer of 1 to 6,
( 3) the compound according to the above (1) , wherein the
lower alkyl represented by R1 which is substituted by a lower
alkoxy is a group of the formula (IIb)

in which n is an integer of 1 to 6,
(4) the compound according to the above (1), wherein the
heterocyclic group which is a substituent for the lower alkyl
represented by R1 is pyridyl optionally having a lower alkyl,
(5) the compound according to the above (1), wherein the
hetero atom of the heterocyclic group represented by R1 is an
oxygen atom,
(6) the compound according to any one of the above (1)
to ( 5) , wherein the lower alkyl represented by R3 is cyclopropyl,
(7) ((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-
(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 2-methoxyethyl ester,
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-
3-(cyclopropylamino)propyl)amino)carbonyl) - 3 -
methylbutyl)carbamic acid 5-methoxy-3-oxapentyl ester,
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-
3-(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 8-methoxy-3,6-dioxaoctyl ester,
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-
3-(cyclopropylamino)propyl)amino)carbonyl) - 3 -
methylbutyl) carbamic acid ll-methoxy-3 , 6 , 9-trioxaundecanyl
ester, or ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2, 3-
dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-(pyridin-2-yl)ethyl ester,
(8) a medicament comprising the compound according to the
above (1) or (7),

(9) the medicament according to the above (8) , which is
a calpain inhibitor,
(10) the medicament according to the above (9) , which is
a therapeutic agent for a disease related to calpain, and
(11) the medicament according to the above (10), wherein
the disease related to calpain is ischemic disease, immunologic
disease, multiple sclerosis, Alzheimer's disease,
osteoporosis, diseases caused by brain tissue damage, cataract,
glaucoma, retinal disease, retinochoroiditis, posterior
eyeball complications due to photocoagulation or a disease
involving neovascularization.
The compound of the present invention is a calpain
inhibitor which is well absorbed orally and exhibits durability
of good blood level, and thus said compound can be used as an
agent for prophylaxis or treatment of diseases related to
calpain such as ischemic disease, immunologic disease, multiple
sclerosis, Alzheimer's disease, osteoporosis, diseases caused
by brain tissue damage, cataract, glaucoma, retinochoroiditis
flisease (diabetic retinopathy, retinal vein occulusion,
macular degeneration, retinitis pigmentosa, hypertensive
retinopathy, retinal detachment, etc.), posterior eyeball
complications due to photocoagulation (e.g. macular edema,
retinal detachment, optic neuritis, visual field defect, light
sense defect, dyschromatopsia, etc.), a disease involving
neovascularization and the like.
Since the compound of the present invention has high oral
absorbability, a medicament containing the compound of the
present invention can be administered orally.

In addition, the compound of the present invention has
low toxicity, and thus can be used safely.
Brief Description of the Accompanying Drawing
Fig. 1: A graph showing viable cell count in the ganglion
cell layer after 7-day retinal ischemia reperfusion in rats.
Each column represents the mean ± S.E. In the graph, "Normal"
means a normal group (n=8), "Control" means a control group
(n=8) , and "Compound 17" means a group to which compound 17 is
administered (n=9). The symbol (*) shows significant
difference (P control group.
Best Mode for Carrying Out the Invention
In the above formula (I), preferable examples of lower
alkyl as the lower alkyl substituted by a lower alkoxy or a
heterocyclic group represented by R1 include a straight or
branched C1-6 alkyl group, specifically, methyl, ethyl, propyl,
isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl,
isopentyl, neopentyl, tert-pentyl, 1-methylbutyl,
2-methylbutyl, 1,2-dimethylpropyl, hexyl, 1-methylpentyl,
2-methylpentyl, 3-methylpenty1, 4-methylpenty1,
1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl,
2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl,
1-ethylbutyl, 2-ethylbutyl, 1-ethyl-2-methylpropyl,
1,1,2-trimethylpropyl, etc. More preferable examples of the
lower alkyl for R1 include a straight or branched C2-3 alkyl group ,
and the most preferable example includes ethyl.
A preferable example of the lower alkoxy which is a

substituent for the lower alkyl represented by R1 includes a
C1-6 lower alkoxy such as methoxy, ethoxy, propoxy, isopropoxy,
butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy,
isopentyloxy, neopentyloxy, tert-pentyloxy, 1-methylbutoxy,
2-methylbutoxy, 1,2-dimethylpropoxy, hexyloxy,
1-methylpentyloxy, 2-methylpentyloxy, 3-methylpentyloxy,
4-methylpentyloxy, 1,1-dimethylbutoxy, 1,2-dimethylbutoxy,
1,3-dimethylbutoxy, 2,2-dimethylbutoxy, 2,3-dimethylbutoxy,
3,3-dimethylbutoxy, 1-ethylbutoxy, 2-ethylbutoxy,
l-ethyl-2-methylpropoxy, 1,1,2-trimethylpropoxy, etc. Said
alkoxy groupwhich is further substituted by said lower alkoxy
may be used preferably.
A preferable example of the lower alkyl represented by
R1 which is substituted by a lower alkoxy includes a group the
formula (Ha)

in which R4 is a lower alkyl, R5 is a lower alkylene, and m is
an integer of 1 to 6, and more preferable example includes a
group of the formula (IIb)

in which n is an integer of 1 to 6.
Examples of the lower alkyl represented by R4 in the above
formula (IIa) include methyl, ethyl, propyl, isopropyl, butyl,
isobutyl, sec-butyl, tert-butyl, etc., preferably methyl,
isopropyl or tert-butyl, and more preferably methyl.

A preferable example of the lower alkylene represented
by R5 in the above formula (IIa) includes a C1-4 alkylene,
specifically methylene, ethylene, trimethylene and
tetramethylene, and a more preferable example is ethylene. The
lower alkylene represented by R5 may have a substituent.
Examples of the substituent include methyl, ethyl, etc.
In the above formula (IIa), m is an integer of 1 to 6,
preferably an integer of 2 to 5. In the above formula (IIb),
n is an integer of 1 to 6, preferably an integer of 1 to 5, and
more preferably an integer of 2 to 5.
A preferable example of the heterocyclic group which is
a substituent for the lower alkyl represented by R1 includes
a pyridyl optionally having a lower alkyl. Examples of the
pyridyl include 2-pyridyl, 3-pyridyl and 4-pyridyl. A
preferable example of the lower alkyl optionally included in
said pyridyl is a C1-3 lower alkyl, specifically, methyl, ethyl,
propyl, isopropyl, etc.
Examples of the heterocyclic group represented by R1
include 5- to 7-membered aromatic group containing one to three
atom(s) identically or differently selected from the group
consisting of sulfur, oxygen and nitrogen, or partially or fully
reduced, saturated heterocyclic group, and specific examples
thereof include furyl, thienyl, pyrrolyl, azepinyl, pyrazolyl,
imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl,
1,2,3-oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl,
pyranyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl,
morpholinyl, thiomorpholinyl, pyrrolidinyl, pyrrolinyl,
imidazolidinyl, pyrazolidinyl, piperidinyl, piperazinyl,
oxazolidinyl, isoxazolidinyl, thiazolidinyl, pyrazolidinyl.

tetrahydrofuranyl, tetrahydropyranyl, tetrahydrothiophenyl,
etc. , preferably saturated heterocyclic group, more preferably
5- to 7-membered saturated heterocyclic group containing oxygen
atom(s), and most preferably tetrahydrofuranyl,
tetrahydropyranyl, etc.
Examples of the lower alkyl represented by R2 are the same
as the said lower alkyl as the lower alkyl substituted by a lower
alkoxy or a heterocyclic group represented by R1, and include
preferably methyl, ethyl and isobutyl. The lower alkyl
represented by R2 is preferably substituted by a phenyl group.
Preferable examples of such phenyl-substituted lower alkyl
group include benzyl, phenethyl, etc.
Examples of the lower alkyl represented by R3 are the same
as the said lower alkyl as the lower alkyl substituted by a
lower alkoxy or a heterocyclic group represented by R1, and may
include a cycloalkyl group. Such cycloalkyl group can be
cyclopropane, cyclobutane, cyclopentane, cyclohexane, etc.,
among which cyclopropane and cyclobutane are preferable.
Examples of the halogen by which the above lower alkyl
group may be substituted include fluorine, chlorine, bromine,
etc., among which fluorine is preferable.
Examples of the fused polycyclic hydrocarbon group
include indanyl, indenyl, naphthyl, pentalenyl, azulenyl, etc. ,
among which indanyl is preferable.
In addition, the compounds of the present invention
include a variety of solvates, polymorphs and pro-drugs.
The compounds of the present invention can be prepared,
for example, according to the following method.

(wherein R is a protecting group, and other groups have the same
meaning as defined above)
Step a is a process which comprises adding a protecting
group into an amino group of amino acids of the formula (III) ,
converting the protected product into a mixed anhydride, and
reducing the mixed anhydride with a reducing agent to yield a
compound of the formula (V) (hereinafter referred to as compound
(V)). The above-mentioned addition and deprotection
procedures of the protecting group(s) can be carried out by the
conventional method. Examples of such protecting groups used
are formyl, optionally substituted C1-6 alkylcarbonyl (e.g.
acetyl, propionyl, etc.), optionally substituted
phenylcarbonyl, optionally substituted C1-6 alkyl-oxycarbonyl

(e.g. methoxycarbonyl, ethoxycarbonyl, tert-butoxycarbonyl,
etc.), optionally substituted phenyloxycarbonyl and
optionally substituted C7-10 aralkyloxycarbonyl (e.g.
phenyl-C1-4 alkyloxycarbonyl such as benzyloxycarbonyl, etc.) .
As the substituent, halogen (e.g. fluorine, chlorine, bromine,
iodine, etc. ) , nitro or the like is used, and the number of such
substituents is approximately 1 to 3. Preferable substituent
may be tert-butoxycarbonyl (Boc).
Examples of the reducing agent used in the above reaction
include lithium aluminum hydride, sodium borohydride, sodium
bis(2-methoxyethoxy)aluminum hydride or the like, among which
sodium borohydride is preferable. The reaction temperature is
-40°C to 30°C, preferably -20°C to 0°C.
The compound (V) may be prepared by adding an
amino-protecting group to an amino alcohol of the formula (IV)
in a similar manner (step a').
Step b is a process of oxidizing a compound (V) with
dimethyl sulfoxide (DMSO) in the presence of an activating
reagent for DMSO to yield a compound of the formula (VI)
(hereinafter referred to as compound (VI) ) . The DMSO oxidation
can be carried out by the conventional method. For example,
the compound (V) is dissolved in DMSO alone or in a mixture of
DMSO and a solvent not inhibiting the oxidation (e.g.
tetrahydrofuran, dichloromethane, chloroform, ethyl acetate,
benzene, ether, etc.), and diisopropylethylamine is usually
added thereto in an amount of approximately 1- to 10-fold in
a molar ratio per one mole of compound (V) . The amount of DMSO
used in the above reaction is approximately 1 to 20 mL to 1 g
of compound (V). As the above activating reagent for DMSO,

there are advantageously employed sulfur trioxide- pyridine
complex, oxalyl chloride, dicyclohexylcarbodiimide, acetic
anhydride or the like. Inter alia, sulfur trioxide-pyridine
complex is preferably used.
Step c is a process of preparing a compound of the formula
(VII) (hereinafter referred to as compound (VII)) as a
diastereomer mixture, which comprises treating a compound (VI)
with sodium hydrogen sulfite, reacting the product with sodium
cyanide to yield a cyanohydrin compound, hydrolyzing the
cyanohydrin compound with an acid or alkali catalyst without
purification to yield a diastereomer mixture of
α-hydroxy-β-amino acid, and adding again the above
amino-protecting group to the α-hydroxy-β-amino acid in a
similar manner.
This hydrolysis reaction is carried out by heating or by
heating under reflux with an acid (e.g. hydrochloric acid,
sulfuric acid, acetic acid, formic acid, etc. ) or an alkali (e.g .
sodium hydroxide, potassium hydroxide, barium hydroxide, etc.) .
The heating temperature is about 50°C to about 100°C. As the
solvent, a mixture of water and an organic solvent (e.g. dioxane ,
tetrahydrofuran, etc.) is preferably used.
Step d is a process of condensing a compound (VII) with
a variety of amines to yield a compound of the formula (VIII)
(hereinafter referred to as VIII).
As to an amine, a suitable amine can be appropriately
selected depending on the objective compound. Examples of such
amines include ethylamine, propylamine, cyclopropylamine,
butylamine, cyclobutylamine, methoxyethylamine,
2-phenoxyethylamine, 2-aminoindane,

2,2,2-trifluoroethylamine or the like.
It is preferable to carry out the above condensation in
the presence of a dehydrative condensing agent such as
1 - ethyl - 3 - (3 - dimethylaminopropyl) carbodiimide hydrochloride,
N,N-dicyclohexylcarbodiimide, etc. Examples of the organic
solvent used in the condensation reaction include
N,N-dimethylformamide, DMSO, tetrahydrofuran,
dichloromethane, methanol, ethanol, benzene, toluene, ethyl
acetate, etc., and a mixture thereof, among which
N,N-dimethylformamide is preferable. The reaction
temperature is within the range of ice-cooling to room
temperature.
The step e is a process of deprotecting amino-protecting
group(s) of a compound (VIII) under acidic condition with
hydrochloric acid to yield an amine hydrochloride of the formula
(IX) (hereinafter referred to as compound (IX)). Such
deprotection of amino-protecting group(s) can be carried out
by the conventional method. For example, the compound (VIII)
is dissolved in an organic solvent which is commonly used, and
then the solution is stirred in the presence of an acid to remove
the amino-protecting group(s). Examples of the acid include
hydrochloric acid, trifluoroacetic acid, p-toluenesulfonic
acid or the like. Alternatively, commercially available
HCl/ethyl acetate or HCl/dioxane may be used to remove
amino-protecting group(s) . The reaction temperature is within
the range of ice-cooling to room temperature.
Step f is a process of condensing a compound of the formula
(IX) with a compound of the formula (X) (hereinafter referred
to as compound (X) ) in the presence of triethylamine to yield

a compound of the formula (XI) (hereinafter referred to as
compound (XI).
The above compound (X) can be prepared according to the
general reaction scheme given below.

(wherein each symbol has the same meaning as defined above)
An alcohol of the formula (XIII) (hereinafter referred
to as alcohol (XIII)) is reacted with di(N-succinimidyl)
carbonate to yield a mixed carbonic ester of the formula (XIV) ,
which is then condensed with L-leucine ethyl ester
hydrochloride in the presence of triethylamine to yield a
compound of the formula (XV). Alkali saponification of the
compound (XV) affords a compound of the formula (XVI)
(hereinafter referred to as (XVI)). Alternatively, the
compound (XVI) may be obtained by direct reaction between
L-leucine and chloroformate. The compound (XVI) is reacted
with hydroxysuccinimide (HOSu) to yield a succinimide ester of
the formula (X) (hereinafter referred to as compound (X)).

Step g is a process of oxidation of a compound. (XI) to
produce a compound of the formula (XII) (hereinafter referred
to as compound (XII). The oxidation reaction is carried out
by per se conventional methods , including those classified into
(i) chromium oxidation such as pyridinium dichromate (PDC)
oxidation, pyridinium chlorochrornate (PCC) oxidation, Jones
oxidation and Collins oxidation, and (ii) DMSO oxidation such
as Swern oxidation, DMSO/sulfur trioxide-pyridine complex
oxidation, DMSO/dicyclohexcylcarbodiimide oxidation,
DMSO/oxalyl chloride oxidation, Dess-Martin oxidation using
Dess-Martin , periodinane, hypohalogen acid oxidation and
N-halogenocarboxylic amide oxidation, among which Dess-Martin
oxidation is preferable. In carrying out Dess-Martin
oxidation, the compound (XI) is dissolved in a commonly used
organic solvent and Dess-Martin reagent is added thereto.
Examples of the commonly used organic solvents include
conventional solvents not adversely affecting the reaction or
a mixture thereof, such as dichloromethane, N,N-
dimethylformamide, DMSO, tetrahydrofuran, methanol, ethanol,
benzene, toluene, ethyl acetate or the like, among which
dichloromethane is preferable. The amount of the Dess-Martin
reagent is approximately 1- to 20-fold mole equivalents,
preferably 1- to 3-fold mole equivalents of the compound (XI).
The reaction temperature is not particularly limited, and it
is within the range of ice-cooling to room temperature. The
compound (XII) thus obtained can be separated and purified by
conventional methods including, for example, concentration,
concentration in vacuo, solvent extraction, crystallization,
recrystallization, solvent transfer, chromatography or the

like.
The each step as mentioned above is carried out in a
commonly used solvent not adversely affecting the reaction, and
a mixture thereof. Examples of such a solvent not adversely
affecting the reaction include dichloromethane,
N,N-dimethylformamide, DMSO, tetrahydrofuran, methanol,
ethanol, benzene, toluene, ethyl acetate or the like.
Specific examples of compounds (I) of the formula
prepared according to the above method include
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-
(ethylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 1),
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-
(ethylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid (3S)-tetrahydro-furan-3-yl
ester(Compound 2),
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-
(ethylamino)propyl)amino)carbonyl)-3-methylbutyl)carbamic
acid tetrahydro-4H-pyran-4-yl ester (Compound 3),
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-
(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 4),
((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3-
dioxo-propyl)amino)carbonyl)-3-methylbutyl)carbamic acid
(3S)-tetrahydro-furan-3-yl ester (Compound 5),
((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2,3-
dioxo-propyl)amino)carbonyl)-3-methylbutyl)carbamic acid
tetrahydro-4H-pyran-4-yl ester (Compound 6),
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-

(propylamine)) propyl) amino) carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 7),
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-
(cyclobutylamino) propyl) amino) carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 8),
((1S)-1-((((1S)-1-benzyl-3-butylamino-2,3-
dioxo -propyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid
2-methoxyethyl ester (Compound 9),
((1S)-1-((((1S)-1-benzyl~2,3-dioxo-3-(2,2,2-
trif luoroethylamino) propyl) amino) carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 10) ,
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-(2-
indanylamino) propyl) amino) carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 11) ,
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-(2-
methoxyethylamino) propyl) amino) carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 12) ,
((1S)-1-((((1S)-2,3-Dioxo-3-ethylamino-1-
(phenylethyl) propyl) amino) carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 13) ,
((1S)-1-((((1S)-2,3-dioxo-3-ethylamino-1-
(phenylethyl)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid (3S)-tetrahydro-furan-3-yl ester
(Compound 14),
((1S)-1-((((1S)-2,3-dioxo-3-cyclopropylamino-1-
(phenylethyl)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 15) ,
((1S)-1-((((1S)-2,3-dioxo-3-cyclopropylamino-1-
(phenylethyl)propyl)amino)carbonyl)-3-

methylbutyl)carbamic acid (3S)-tetrahydro-furan-3-yl ester
(Compound 16),
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-
(cyclopropylamino)propyl)amino)carbony1)-3-
methylbutyl) carbamic acid 5-methoxy-3-oxapentyl ester
(Compound 17),
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-
(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 8-methoxy-3,6-dioxaoctyl ester
(Compound 18),
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-
(cyclopropylamino)propyl)amino)carbonyl) - 3 -
methylbutyl) carbamic acid 11-methoxy-3, 6, 9-trioxaundecanyl
ester (Compound 19),
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-
(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 14-methoxy-3,6,9,12-
tetraoxa-tetradecanyl ester (Compound 20),
((1S)-1-((((1S)-2,3-dioxo-1-(2-methylpropyl)-3-(2-
phenoxyethyl)aminopropyl)amino)carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester(Compound 21),
((1S)-1-((((1S)-2.3-dioxo-1-(2-methylpropyl)-3-(2-
phenoxyethyl)aminopropyl)amino)carbonyl)-3-
methylbutyl) carbamic acid 5-methoxy-3-oxa-pentyl ester
(Compound 22),
((1S)-1-((((1RS)-3-amino-1-benzyl-2,3-dioxo-
propyl)amino)carbonyl)-3-methylbutyl)carbamic acid
5-methoxy-3-oxa-pentyl ester (Compound 23),
((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3-

dioxo-propyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-(pyridin-2-yl)ethyl ester (Compound 24),
( (lS)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3-
dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-(6-methylpyridin-2-yl)ethyl ester (Compound 25),
((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3-
dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-(5-ethylpyridin-2-yl)ethyl ester (Compound 26),
((1S)-1-((((1S)-1-benzyl-3~(cyclopropylamino)-2,3-
dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-tert-butoxyethyl ester (Compound 27),
((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3-
dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-isopropoxyethyl ester (Compound 28) and the like, among which
compounds 4, 17, 18, 19 and 24 are preferable.
These compounds of the present invention have not yet been
reported in literatures, and thus are novel. As shown in Test
Examples which will be hereinafter described, the compounds of
the present invention have an excellent calpain inhibitory
activity. Accordingly, a medicament containing a compound of
the present invention as active ingredient, optionally together
with a combination of carriers which will be hereinafter
described, is useful as a calpain inhibitor.
The medicament containing a compound of the present
invention is useful as a prophylactic or therapeutic agent for
mammal (e.g. human, rat, mouse, rabbit, cattle, pig, dog, cat)
diseases related to calpain such as ischemic disease,
immunologic disease, multiple sclerosis, Alzheimer's disease,
osteoporosis , diseases caused by brain tissue damage, cataract,

glaucoma, retinochoroiditis disease (diabetic retinopathy,
retinal vein occulusion, macular degeneration, retinitis
pigmentosa, hypertensive retinopathy, retinal detachment,
etc.), posterior eyeball complications due to photocoagulation
(e.g. macular edema, retinal detachment, optic neuritis, visual
field defect, light sense defect, dyschromatopsia, etc.), a
disease involving neovascularization or the like.
In addition, a compound of the present invention has
excellent tissue transport and high absorbability as well as
high safety with very low toxicity.
The medicament containing a compound of the present
invention can be administered systemically or locally.
Besides oral administration. The systemic administration
includes, besides oral administration, parenteral
administration route such as intravenous injection,
subcutaneous injection, intramuscular injection or the like.
In case of the local administration, the medicament is applied
via transdermal, mucous membrane, nasal or ophthalmic route,
etc.
The dosage form of the medicament containing a compound
of the present invention includes solid preparations (e.g.
powders, granules, tablets, capsules, suppositories, etc.) and
liquid preparations (e.g. syrups, injections, eyedrops, nasal
drops, etc.). In the production of granules or tablets, any
dosage form can be prepared with the use of pharmaceutically
acceptable additives such as excipients (e.g. lactose, sucrose,
glucose, starch, crystalline cellulose, etc.), lubricants (e.g.
magnesium stearate, talc, stearic acid, calcium stearate),
disintegrators (e.g. starch, carmellose sodium, calcium

carbonate, etc.), or binders (e.g. starch paste,
hydroxypropylcellulose solution, carmellose solution, gum
arable solution, gelatin solution, sodium alginate solution,
etc.). Further, granules and tablets may be coated with a
coating agent (e.g. gelatin, white sugar, gum arable, carnauba
wax, etc.) or an enteric coating agent (e.g. cellulose acetate
phthalate, methacrylic copolymer, hydroxypropylcellulose
phthalate, carboxymethylethyl cellulose, etc.).
In the production of capsules, conventional excipients
such as magnesium stearate, calcium stearate, talc and light
silicic acid, anhydride, etc., for improving flowability and
lubricity; crystalline cellulose and lactose for increasing
flowability under pressure; and the above-mentioned
disintegrators are appropriately selected, and mixed or
granulated homogenously with the compound of the present
invention, then filled in capsules. Alternatively, the
granulated products may be coated with a suitable coating agent,
then filled in capsules, or may be encapsulated with an
appropriate capsule base (e.g. glycerin) having increased
plasticity endowed with addition of glycerin or sorbitol. If
required, coloring agents, preservatives (e.g. sulfur dioxide,
parabens such as methyl p-oxybenzoate, ethyl p-oxybenzoate and
propyl p-oxybenzoate), etc. may be added to the capsule
preparations. Enteric coated capsules, gastric resistant
capsules or release controlled capsules may be formulated in
addition to conventional capsule preparations. In the case of
enteric coated capsule preparations, they are prepared by
filling regular capsules with the compound of the present
invention which is coated with an enteric coating agent or to

which said appropriate excipient is added, or alternatively,
they are prepared by filling capsules coated with an enteric
coating agent or capsules made from an enteric polymer as a base
material with the compound of the present invention optionally
together with said appropriate excipient. In the production
of suppositories, an appropriate suppository base (e.g. cacao
butter, macrogol, etc.) can be used.
In the production of syrups, stabilizers (e.g. sodium
edetate, etc.), suspending agents (e.g. gum arablc, carmellose,
etc.), corrigents (e.g. simple syrup, glucose, etc.), perfumes
or the like can be appropriately used.
Injections, eye-drops or nasal drops of the present
invention can be produced by dissolving or dispersing the
compound of the present invention in a solution containing an
appropriate isotonic (e.g. sodium chloride, potassium chloride,
glycerin, mannitol, sorbitol, boric . acid, borax, glucose,
propylene glycol, etc.), buffer (e.g. phosphate buffer, acetate
buffer, borate buffer, carbonate buffer, citrate buffer, Tris
buffer, glutamate buffer, e-aminocapronate buffer, etc.),
preservative (e.g. methyl p-oxybenzoate, ethyl p-oxybenzoate,
propyl p-oxybenzoate, chlorobutanol, benzyl alcohol,
benzalkonium chloride, sodium dehydroacetate, sodium edetate,
boric acid, borax, etc.), thickener (e.g.
hydroxyethylcellulose, hydroxypropylcellulose, polyvinyl
alcohol, polyethylene glycol, etc.), stabilizer (e.g. sodium
hydrogensulfite, sodium thiosulfate, sodium edetate, sodium
citrate, ascorbic acid, dibutylhydroxytoluene, etc.), pH
controlling agent (e.g. hydrochloric acid, sodium hydroxide,
phosphoric acid, acetic acid, etc.) or the like.

Although the amount of the additive to the above injection,
eye drop or nasal drop depends on the kind and the purpose of
the additive to be added, it is sufficient to add the amount
of the additive that can achieve the purpose. Usually, an
isotonic is preferably added in an amount of about 0.5 to about
5.0 w/v % so that the osmotic pressure reaches about 229 mOsm
to about 343 mOsm. Preferred concentrations of buffer,
thickner and stabilizer to be added are about 0.01 to about 2.0
w/v %, about 0.01 to about 1.0 w/v % and about 0.001 to about
1.0 w/v %, respectively. A pH controlling agent is
appropriately added to adjust the pH usually to about 3 to about
9, preferably about 4 to about 8.
The dose of the compound of the present invention depends
on the target diseases, symptom of the disease, subject to be
administered, administration route or the like. For example,
in the case of oral administration to an adult patient, the dose
is about 1 to about 200 mg, preferably about 10 to about 100
mg for a single dose, once to several times a day. In the case
of injection to an adult patient, the dose is about 0.1 to about
50 mg, preferably about 1 to about 30 mg, once a day. For topical
administration to the eyes, it is preferable to administer eye
drops containing usually about 0.001 to about 1.0 w/v %,
preferably about 0.01 to about 0.5 w/v %, in an amount of about
20 to about 50 µL per dose, several times a day.
Examples
The present invention will be explained in detail by way
of Reference Examples, Examples, Test Examples and Formulation
Examples, however, the invention is not restricted thereto.

In the analytical data of the compounds described in the
Examples, melting points were determined on a Yanaco micro
melting point apparatus without correction. 1H-NMR spectra
were recorded on a Varian Gemini-2000 spectrometer. Chemical
shifts are reported in parts per million, and coupling constants
(J) are reported in hertz. Matrix-assisted laser desorption
ionization time-of-flight mass spectra (MALDI-TOF-MS) were
obtained on a Perseptive Voyager DE mass spectrometer, and the
mass numbers were corrected with an internal standard
(a-cyano-4-hydroxycinnamic acid) and displayed accurately.
Reference Example 1
N- ((2-Methoxyethoxy)carbonyl)-1-leucine N-hydroxy-
succinimide ester
(1) To a solution of L-leucine (25 g, 0.19 mol) was
dissolved in 2M NaOH (0.12 L) was slowly added 2-methoxyethyl
chloroformate (30 g, 0.22 mol) and 1M NaOH at the same time
under the ice-cooled condition. The mixture was stirred at room
temperature for 18 hours, diluted into water (600 mL) and washed
with ethyl ether (2 x 200 mL) . The aqueous phase was cooled
in an ice bath and acidified to pH 3 with 6M HC1. This mixture
was extracted with ethyl acetate (EtOAc) (5 x 150 mL) . The
organic phase was dried over anhydrous MgSO4 and filtered, and
the filtrate was concentrated in vacuo to yield N-((2-
methoxyethoxy)carbonyl)-1-leucine (41 g, 92%) as a colorless
oil.
(2) N-((2-Methoxyethoxy)carbonyl)-1-leucine (20 g, 86
mmol) and N-hydroxysuccinimide (13 g, 0.11 mmol) were dissolved
in THF (200 mL), and a suspension of 1-ehtyl-3-(3-

dimethylaminopropyl)carbodiimide hydrochloride (21 g, 0.11
mol) in CH2Cl2 (200 mL) was added thereto. The mixture was
stirred at room temperature for 18 hours, and concentrated in
vacuo. The residue was dissolved in EtOAc (300 mL), and the
solution was washed with 1M HCl (150 mL), saturated aqueous
NaHCO3 (150 mL) and saturated aqueous NaCl (150 mL) , dried over
anhydrous MgSO4, and concentrated in vacuo to give the title
compound (27 g, 95%) as a colorless oil.
1H-NMR (300MHz,DMSO-d6) δ 0.89 (d,3H,J=6.6),0.93(d,3H,J= 6.6) ,
1.57-1.84(m,3H),2.81(s,4H),3.26(s,3H),3.51(t,2H,J=4.7),
4.10(t,2H,J=4.7),4.40(m,lH),8.04(d,lH,J=8.1).
Reference Example 2
(1)N-(((3S)-Tetrahydrofuran-3-yloxy)carbonyl)-1-
leucine N-hydroxysuccinimide ester
To a stirred solution of (S)-3-hydroxytetrahydrofuran
(1.0 g, 11 mmol) in acetonitrile (50 mL) at room temperature
were added N,N'-disuccinimidyl carbonate (4.3 g, 17 mmol) and
triethylamine (4.4 g, 17 mmol, 4.8 mL) . The resulting mixture
was stirred at room temperature for 18 hours, and concentrated
in vacuo .' The residue was diluted with saturated aqueous NaHCO3
(100 mL) and extracted with EtOAc (200 mL) . The combined
organic extracts were washed with saturated aqueous NaCl (100
mL), dried over anhydrous MgSO4, and concentrated in vacuo to
give N-succinimidyl (3S)-3-tetrahydrofranyl carbonate (2.6 g)
as a brown oil in a quantitative yield.
( 2) To a solution of L-leucine ethyl ester hydrochloride
(2.7 g, 14 mmol) and triethylamine (2.9 g, 2 8 mmol) in
dichloromethane (50 mL) was added a solution of N-succinimidyl

(3S)-3-tetrahydrofurnaylcarbonate (2.6 g, 11 mmol) in
dichloromethane (20 mL), and the mixture was stirred at room
temperature for 18 hours, then concentrated in vacuo. The
residue was dissolved in ethyl acetate (200 mL), and the
solution was washed successively with 1M hydrochloric acid,
saturated aqueous NaHCO3 and saturated aqueous NaCl, dried over
anhydrous magnesium sulfate, and concentrated in vacuo. The
residue was washed with hexane to give
N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine ethyl
ester (3.1 g, 98%) as a white solid.
(3) To a solution of N-(((3S)-tetrahydrofuran-3-
yloxy)carbonyl)-1-leucine ethyl ester (2.9 g, 11 mmol) in EtOH
(100 mL) was added 1M NaOH (33 mL) . The mixture was stirred
under ice-cooling condition for 3 hours, and then adjusted to
pH 3 by the addition of HCl thereto. The solution was
concentrated in vacuo, and the residue was extracted with ethyl
acetate (100mL) . Then, the organic layer was separated, washed
with 1M HCl and saturated aqueous NaCl, dried over anhydrous
MgSO4 and concentrated in vacuo. The residue was crystallized
from ethyl acetate and hexane to give
N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine (2.6 g,
85%) as colorless crystals.
M.p. 94.9-96.0°C
(4) Following the reaction in an analogous manner to
Reference Example 1(2) and using
N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine in
place of N-((2-methoxyethoxy)carbonyl)-1-leucine, there was
obtained the title compound as a colorless oil.
1H-NMR(300MHz,DMSO-d6) δ 0.89 (d,3H,J=6.0),0.92(d, 3H, J=6.3),

1.55-1.82(m,3H),1.88 (m, 1H),2.12(m, 1H),2.81(s,4H), 3.64-3.84
(m,4H),4.39(m,lH),5.l5(m,lH),8.04(d,1H,J=7.8).
Reference Example 3
N- ((Tetrahydro-4H-pyran-4-yloxy)carbonyl) -1-leucine
N-hydroxysuccinimide ester
(1) N-Succinimidyl tetrahydro-4H-pyran-4-ylcarbonate
was obtained as a brown oil in a manner similar to Reference
Example 2(1), using 4-hydroxytetrahydro-4H-pyran in place of
(S)-3-hydroxytetrahydrofuran, there was obtained
N-succinimidyl tetrahydro-4H-pyran-4-ylcarbonate as a brown
oil.
(2) Following the reaction in an analogous manner to
Reference Example 2(2) and using N-succinimidyl tetrahydro-
4H-pyran-4-ylcarbonate in place of N-succinimidyl
(3S)-3-tetrahydrofuranyl carbonate, there was obtained
N-( (tetrahydro-4H-pyran-4-yloxy)carbonyl)-1-leucine ethyl
ester as a colorless solid.
(3) Working up in a manner similar to Reference Example
2(3) and using N-(5-methoxy-3-oxaopentyloxy)carbonyl)-1-
leucine ethyl ester in place of N-(((3S)-tetrahydrofuran-
3-yloxy)carbonyl) -1-leucine ethyl ester, there was obtained N-
((tetrahydro-4H-pyran-4-yloxy)carbonyl)-1-leucine as a
colorless solid.
(4) Using N-((tetrahydro-4H-pyran-4-yloxy)carbonyl)-
L-leucine) in place of N-(2-(methoxyethoxy)carbonyl)-
L-leucine, a similar reaction to Reference Example 1(2) gave
the title compound as a colorless oil.
1H-NMR(300MHz,DMSO-d6) δ 0.89(d,3H,J=6.0),0.92(d,3H,J= 6.3),

1.43-1.93(m,7H),2.80(s,4H),3.42(m,2H),3.78-3.82(m, 2H) , 4.39
(m,1H),4.72(m,1H),7.94(d,1H,J=7.8).
Reference Example 4
N-((5-Methoxy-3-oxapentyloxy)carbonyl)-1-leucine
N-hydroxysuccinimide ester
(1) Following the reaction in an analogous manner to
Reference Example 2(1) and using diethylene glycol monomethyl
ether in place of (S)-3-hydroxytetrahydrofuran, there was
obtained 5-methoxy-3-oxapentyl N-succinimidyl carbonate as a
colorless oil.
(2) Following the reaction in an analogous manner to
Reference Example 2(2) and using 5-methoxy-3-oxapentyl
N-succinimidyl carbonate in place of N-succinimidyl
(3S)-3-tetrahydrofuranyl carbonate, there was obtained
N- ((5-methoxy-3-oxapentyloxy)carbonyl) -1-leucine ethyl ester
as a colorless oil.
(3) Following the reaction in an analogous manner to
Reference Example 2(3) and using N- ((5-methoxy-3-
oxapentyloxy)carbonyl)-1-leucine ethyl ester in place of
N- ((3S)-tetrahydrof uran-3-yloxycarbonyl)-1-leucine ethyl
ester, there was obtained N-((5-methoxy~3-
oxapentyloxy)carbonyl)-1-leucine as a colorless oil.
(4) Following the reaction in an analogous manner to
Reference Example 1(2) and using N- ((5-methoxy-3-
oxapentyloxy)carbonyl)-1-leucine in place of N-((2-
methoxyethoxy)carbonyl-1-leucine, there was obtained the
title compound as a colorless oil.
1H-NMR(300MHz,DMSO-d6) δ 0.90(dd,6H,J=9.5,6.5),1.56-1.80(m.

3H),2.80(s,4H),3.24(s,3H),3.41-3.46(m,2H),3.50-3.54(m,2H),
3.56-3.60(m,2H),4.08-4.11(m,2H),4.39(m,1H),8.05(d,1H,J=7.8).
Reference Example 5
N-((8-Methoxy-3,6-dioxaoctyloxy)carbonyl)-1-leucine
N-hydroxysuccinimide ester
(1) Following the reaction in an analogous manner to
Reference Example 2(1) and using triethylene glycol monomethyl
ether in place of (S)-3-hydroxytetrahydrofuran, there was
obtained 8-methoxy-3,6-dioxaoctyl N-succinimidyl carbonate as
a colorless oil.
(2) Following the reaction in an analogous manner to
Reference Example 2(2) and using 8-methoxy-3,6-dioxaoctyl
N- succinimidyl carbonate in place of N-succinimidyl
(3S)-3-tetrahydrofuranyl carbonate, there was obtained
N-((8-methoxy-3,6-dioxaoctyloxy)carbonyl)-1-leucine ethyl
ester as a colorless oil.
(3) Following the reaction in an analogous manner to
Reference Example 2(3) and using N- (8-methoxy-3,6-
dioxaoctyloxy)carbonyl)-1-leucine ethyl ester in place of
N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl-1-leucine ethyl
ester, there was obtained N-((8-methoxy-3,6-
dioxaoctyloxy)carbonyl)-1-leucine as a colorless oil.
(4) Following the reaction in an analogous manner to
Reference Example 1(2) and using N-((8-methoxy-3,6-
dioxaoctyloxy)carbonyl)-1-leucine in place of N-((2-
methoxyethoxy)carbonyl)-1-leucine, there was obtained the
title compound as a colorless oil.
1H-NMR(300MHz,DMSO-d6) δ 0.89(d,3H,J=6.3),0.92(d,3H,J=6.3),

1.56-1.82(m,3H),2.81(s,4H),3.24(s,3H),3.43(m,2H),3.52(m,
6H),3.59(m,2H),4.10(m,2H),4.40(m,1H),8.06(d,1H,J=7.8).
Reference Example 6
N-((11-Methoxy-3,6,9-trioxaundecanyloxy)carbonyl)-1-
leucine N-hydroxysuccinimide ester
(1) Following the reaction in an analogous manner to
Reference Example 2(1) and using tetraethylene glycol
monomethyl ether in place of (S)-3-hydroxytetrahydrofuran,
there was obtained 111-methoxy-3, 6,9-trioxaundecanyl
N-succinimidyl carbonate as a colorless oil.
(2) Following the reaction in an analogous manner to
Reference Example 2(2) and using
111-methoxy-3, 6 , 9-trioxaundecanyl N-succinimidyl carbonate in
place of N-succinimidyl (3S)-3-tetrahydrofurahyl carbonate,
there was obtained N-((111-methoxy-3,6,9-
trioxaundecanyloxy)carbonyl-1-leucine ethyl ester as a
colorless oil.
(3) Following the reaction in an analogous manner to
Reference Example 2(3) and using N- ((111-methoxy-3,6,9-
trioxa-undecanyloxy)carbonyl-1-leucine ethyl ester in place
of N- (((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine
ethyl ester, there was obtained N- ((111-methoxy-3,6,9-
trioxa-undecanyloxy)carbonyl)-1-leucine as a colorless oil.
(4) Following the reaction in an analogous manner to
Reference Example 1(2) and using N- ((111-methoxy-3,6,9-
trioxaundecanyloxy)carbonyl)-1-leucine in place of N-((2-
methoxyethoxy)carbonyl)-1-leucine, there was obtained the
title compound as a colorless oil.

1H-NMR(300 MHz,DMSO-d6) δ 0. 91 (dd, 6H, J=9 . 3 , 6 . 3) , 1. 56-1. 77(m,
3H),2.81(s,4H),3.24(s,3H),3.41-3.44(m,2H),3.49-3.52(m,10H) ,
3.59(t,2H,J=4.7),4 . 08-4.11(m,2H),4.38(m,1H),8.06(d,1H,J=7 . 8
).
Reference Example 7
N-((14-Methoxy-3,6,9,12-tetraoxatetradecanyloxy)carbonyl)-
L-leucine N-hydroxysuccinimide ester
(1) Following the reaction in an analogous manner to
Reference Example 2(1) and using pentaethylene glycol
monomethyl ether in place of (S)-3-hydroxytetrahydrofuran,
there was obtained 14-methoxy-3 , 6 , 9 ,12-tetraoxa-tetradecanyl
N-succinimidyl carbonate as a colorless oil.
(2) Following the reaction in an analogous manner to
Reference Example 2(2) and using
14-methoxy-3 , 6,9,12-tetraoxa-tetradecanyl AT-succinimidyl
carbonate in place of N-succinimidyl (3S)-3-tetrahydrofuranyl
carbonate, there was obtained N-((14-methoxy-3,6,9,12-
tetraoxa-tetradecanyloxy)carbonyl)-1-leucine ethyl ester as a
colorless oil.
(3) Following the reaction in an analogous manner to
Reference Example 2(3) and using N- ((14-methoxy-3,6,9,12-
tetraoxa-tetradecanyloxy)carbonyl-1-leucine ethyl ester in
place of N-( (3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine
ethyl ester, there was obtained N- ((14-methoxy-3,6,9,12-
tetraoxa-tetradecanyloxy)carbonyl)-1-leucine as a colorless
oil.
(4) Following the reaction in an analogous manner to
Reference Example 1(2) and using N- ((14-methoxy-3,6,9,12-

tetraoxa-tetradecanyloxy)carbonyl L-leucine in place of
N-((2-methoxyethoxy)carbonyl) -1- leucine, there was obtained
the title compound as a colorless oil.
1H-NMR(300MHz,DMSO-d6) δ 0.89(d,3H,J=6.6),0.92(d,3H,J=6.3) ,
1.57-1.82(m,3H),2.81(s.4H),3.24(s,3H),3.43(m,2H),3.51(m,
14H),3.59(m,2H),4.10(m,2H),4.40(m,1H),8.05(d,1H,J=7.8) .
Reference Example 8
(3S) -3-Amino-N-ethyl-2-hydroxy-4-phenylbutanamide
hydrochloride
(1) To a solution of L-phenylalaninol (50 g, 66 mmol)
in tetrahydrofuran (1.3 L) and water (630 mL) , a solution of
di-t-butyl dicaxbonate (140 g, 0.67 mol) in tetrahydrofuran
(500 mL) and 1M NaOH (660 mL) were added slowly at the same time
under ice-cooled condition. The mixture was stirred at room
temperature for 18 hours, concentrated in vacuo, and diluted
with ethyl acetate (EtOAc) (1 L) . The solution was washed with
1M HCl, saturated aq. NaHCO3 and saturated aq. NaCl, dried over
anhydrous MgSO4, and concentrated in vacuo. The resulting
white solid was recrystalized from ethyl acetate/hexane (1:10).
The crystal was filtered off to give N- (tert-butoxycarbonyl) -
L-phenylalaninol (70 g, 84%) as colorless crystals.
(2) N-(tert-Butoxycarbonyl) -1-phenylalaninol (69 g,
0.28 mol) was dissolved in DMSO (280 mL) and CH2Cl2 (140 mL),
and the solution was in an ice-bath. N,N-
diisopropylethylamine (106 g, 0.82 mol) and a suspension of
purified sulfur trioxide pyridine complex (130 g, 0.82 mol) in
DMSO (100 mL) were added thereto. The mixture was stirred for
1 hour under the same condition. The reaction mixture was

diluted with EtOAc (1.5 L) , and the solution was washed with
1M HCl, saturated aqueous NaHCO3 and saturated aqueous NaCl,
dried over anhydrous MgSO4, and concentrated in vacuo. The
residue was crystallized from a mixture of hexane and EtOAc to
give N- (tert-butoxycarbonyl) - L-phenylalaninal (53 g, 77%) as
colorless crystals.
(3) N- (tert-Butoxycarbonyl) -1-phenylalaninal (17 g, 67
mmol) was dissolved in MeOH (100 mL) and chilled to 5 °C. Sodium
bisulfite (7.0 g, 67 mmol) was dissolved in water (150 mL) and
chilled to 5 °C. The solution was added to the aldehyde solution,
and the mixture was stirred at 5°C for 18 hours. NaCN (4.0 g,
81 mmol) was dissolved in water (100 mL) and added with EtOAc
(300 mL) to the above mixture. The reaction solution was
stirred at room temperature for 5 hours. The organic layer was
collected, dried over anhydrous MgSO4, and concentrated in
vacuo to yield the cyanohydrin as a colorless oil. The
cyanohydrin was dissolved in 1,4-dioxane (250 mL) and
concentrated HCl (250 mL) , and 10 mL of anisole was added. The
solution was gently refluxed for 18 hours, allowed to cool to
room temperature and then concentrated in vacuo to give a brown
semi-solid. The residue was dissolved in water (100 mL) and
washed with ethyl ether (3 x 50 mL) . The aqueous phase was then
placed on a Dowex 50X8- column (100-200 mesh, H+ form; 25 x 1.8
cm). The column was washed with water until the pH 5.5, and
eluted with 2M ammonium hydroxide (ca. 1.5 L) . The eluent was
concentrated in vacuo to yield (3S)-3-amino-2-hydroxy-
4-phenylbutanoic acid (12 g, 88%) as a white solid.
(4) (3S) -3-Amino-2-hydroxy—4-phenylbutyric acid (11 g,
56.34 mmol) was dissolved in 1M NaOH (70 mL), and to this

solution was added a solution of di-t-butyl dicarbonate (12 g,
57 mmol) in dioxane (70 mL) . The mixture was stirred at room
temperature for 18 hours while the pH was maintained between
10 and 11 with 1M NaOH. The mixture was diluted with water (600
mL) , and washed with diethyl ether (2 x 200 mL) . The aqueous
phase was chilled in an ice bath and acidified to pH 2 with 1M
HCl. This mixture was extracted with ethyl ether (3 x 250 mL) .
The organic phase was dried over anhydrous MgSO4 and
concentrated in vacuo to yield (3S)-3-(tert-
butoxycarbonylamino) -2-hydroxy-4- phenylbutanoic acid (12 g,
72%) as a mixture of diastereomer which was a colorless solid.
(5) (3S)-3-(tert-Butoxycarbonylamino)-2-hydroxy-4-
phenylbutanoic acid ( 6 . 3 g, 21 mmol) and 1-hydroxybenzotriazole
(HOBt) (3.0 g, 22. 4 mmol) were dissolved in DMF (45mL) and cooled
in an ice bath. 1-Ethyl-3-(S-dimethylaminopropyl)carbodi-
imide hydrochloride (EDC) (4.6 g, 24 mmol) was added, followed
by aqueous ethylamine solution (3.0 mL). The solution was
stirred for 18 hours. The solution was diluted into EtOAc (200
mL) and washed with 1M HCl, saturated aqueous NaHCO3, and
saturated aqueous NaCl. The organic layer was dried over
anhydrous MgSO4 and concentrated in vacuo to yield
((1S)-1-benzyl-3-ethylamino-2-hydroxy-3-oxo-
propyl)carbamic acid 1,1- dimethylethyl ester (5.8 g, 84%) as
a white solid.
(6)((1S)-1-Benzyl-3-ethylamino-2-hydroxy-3-
oxopropyl)carbamic acid 1,1-dimethylethyl ester (5.5 g, 17
mmol) was dissolved in 4N HCl/dioxane (65 mL) and was stirred
for 3 hours at room temperature. The solution was concentrated
in vacuo to yield the title compound as a white solid (4.4 g)

in a quantitative yield.
M.p. 162.8-163.3°C.
(Major)1H-NMR(300MHz,DMSO-d6) δ 1.02(t,3H,J=7.2),2.93(m,2H),
3.05-3.20(m,2H),3.60(m,1H),3.88 (m,1H),6.75 (d,1H,3=6.0),
7.19-7.37(m,5H),8.08(m,1H),8.17(br s,3H).
(Minor ) 1H-NMR(300MHz ,DMSO-d6) δ 0 . 97 (t, 3H, J=7 . 4) , 2 . 80(d, 2H, J
=6.9),3.00(m,2H),3.69(m,1H),4.26(m,1H).6.53(d,1H,J=5.4),
7.19-7.37(m,5H),8.03(t,1H,J=5.7),8.17(br s,3H).
Reference Example 9
(3S)-3-Amino-N-cyclopropyl-2-hydroxy-4-phenylbutanamide
hydrochloride
Following the reaction in an analogous manner to
Reference Example 8(5) and using cyclopropylamine in place of
aqueous ethylamine, there was obtained ((1S)-1-benzyl-3-
cyclopropylamino-2-hydroxy-3-oxopropyl)carbamic acid
1,1-dimethylethyl ester as a white solid.
Following the reaction in an analogous manner to
Reference Example 8(6) and using ((1S)-1-benzyl-3-
cyclopropylamino-2-hydroxy-3-oxopropyl)carbamic acid
1,1-dimethyl ester in place of ((1S)-1-benzyl-3-
ethylamino-2-hydroxy-3-oxopropyl)carbamic acid 1,1- dimethyl
ethyl ester, there was obtained the title compound as a white
solid.
M.p. 162.9-163.3°C
1H-NMR(300MHz ,DMSO-d6) δ 0.44(m,2H),0.57(m,2H),2.50(m,0.5H),
2.65(m,0.5H),2.82(d,1H,J=6.9),2.94(m,1H),3.60(m,0.5H),3.70
(m,0.5H),3.87(m,0.5H),4.26(d,0.5H,J=2.4),6.45(br s,0.5H),
6.69(br s,0.5H),7.23-7.35(m,5H),7.99(d,0.5H,J=4.2),8.08(br

s,1.5H),8.09(d,0.5H,J=4.5),8.23(br s,1.5H).
Reference Example 10
(3S)-3-Amino-2-hydroxy-4-phenyl-W-propylbutanamide
hydrochloride
Following the reaction in an analogous manner to
Reference Example 8(5) and using propylamine in place of aqueous
ethylamine, there was obtained
((1S)-1-benzyl-2-hydroxy-3-oxo-3-
(propylamino)propyl)carbamic acid 1,1-dimethylethyl ester as
a white solid.
Following the reaction in an analogous manner to
Reference Example 8(6) and using ((1S)-1-benzyl-2-hydroxy-
3-OXO-3-(propylamino)propyl)carbamic acid 1,1-dimethylethyl
ester in place of ((1S)-1-benzyl-3-ethylamino-2-hydroxy-3-
oxopropyl)carbamic acid 1,1-dimethylethyl ester, there was
obtained the title compound as a white solid.
M.p. 127.8-129.5°C
1H-NMR(300MHz ,DMSO-d6) δ 0.82(m,3H) , 1. 35-1. 47(m, 2H) ,2.82 (m,
0.5H),2.95(m,3H),3.09(m,0.5H),3.58(m,0.5H),3.70(m,0.5H),
3.92(m,0.'5H),4.31(m,0.5H) , 6 . 55 (d, 0 . 5H, J=4 .8) , 6 . 77 (d, 0 . 5H,
J=6.6),7.21-7.36(m,5H),7.98-8.15(m,2.5H),8.24(br s,1.5H).
Reference Example 11
(3S) -3- Amino-AT-cyclobutyl- 2 -hydroxy- 4 -phenylbutanamide
hydrochloride
Following the reaction in an analogous manner to
Reference Example 8(5) and using cyclobutylamine in place of
aqueous ethylamine, there was obtained ((1S)-1-benzyl-3-

cyclobutylamino - 2 -hydroxy- 3 - oxopropyl) carbamic acid 1,1-
dimethylethyl ester as a white solid.
Following the reaction in an analogous manner to
Reference Example 8(6) and using ((1S)-1-benzyl-3-
cyclobu tylamino - 2 -hydroxy- 3 - oxopropyl) carbamic acid
1,1-dimethylethy1 ester in place of ((1S)-1-benzyl-3-
ethylamino-2-hydroxy-3-oxopropyl) carbamic acid 1,1-
dimethylethyl ester, there was obtained the title compound as
a white solid.
M.p.l62.5-163°C.
1H-NMR(300 MHz,DMSO-d6) δ 1.59(m,2H),1.88-2.18(m,4H),2.80(d,
1H,J=6.6),2.91(m,1H),3.58(m,0.5H),3.69(m,0.5H),3.87(m,
0.5H),4.08(m,0.5H),4.16-4.24(m,1H),6.50(d,0.5H,J=5.4),
6.72(d,0.5H,J=6.0),7.21-7.33(m,5H),8.05(br s,1.5H),8.19(d,
0.5H,J=7.8),8.20(br s,1.5H),8.29(d,0.5H,J=8.1).
Reference Example 12
(3S)-3-Amino-N-butyl-2-hydroxy-4-phenyl-butanamide
hydrochloride
Following the reaction in an analogous manner to
Reference Example 8(5) and using butylamine in place of aqueous
ethylamine, there was obtained ((1S)-1-benzyl-3-butylamino-
2-hydroxy-3-oxopropyl)carbamic acid 1,1-dimethylethy1 ester
as a white solid.
Following the reaction in an analogous manner to
Reference Example 8(6) and using ((1S)-1-benzyl-3-butylamino-
2-hydroxy-3-oxopropyl)carbamic acid 1,1-dimethylethyl ester
in place of ((1S)-1-benzyl-3-ethylamino-2-hydroxy-3-
oxopropyl)carbamic acid 1,1-dimethylethyl ester, there was

obtained the title compound as a white solid.
M.p. 141.0-141.4°C
1H-NMR(300MHz,DMSO-d6) δ 0 .86 (m, 3H) , 1.16-1. 47(m, 4H) , 2 . 80 (m,
0.5H),2.99(m,3H).3.13(m,0.5H),3.57(m,0.5H),3.70 (m,0.5H),
3.92(m,0.5H),4.30(m,0.5H),6.53(br s,0.5H),6.77(d,0.5H,J=
6.6),7.19-7.39 (m,5H),7.97-8.15(m,2.5H),8.22(s,1.5H).
Reference Example 13
(3S)-3-Amino-2-hydroxy-4-phenyl-N~ (2,2,2-
trifluoroethyl)butanamide hydrochloride
Following the reaction in an analogous manner to
Reference Example 8(5) and using 2 , 2 , 2-trif luoroethylamine in
place of aqueous ethylamine, there was obtained ((1S)-1-
benzyl-2-hydroxy-3-oxo-3-(2,2,2-
trifluoroethylamino)propyl)carbamic acid 1,1-dimethylethy1
ester as a white solid.
Following the reaction in an analogous manner to
Reference Example 8(6) and using
((1S)-1-benzyl-2-hydroxy-3-oxo-3-(2,2,2-
trifluoroethylamino)propyl)carbamic acid 1,1-dimethylethyl
ester in place of (((1S)-1-benzyl-3-ethylamino-2-hydroxy-
3-oxopropyl)carbamic acid 1,1-dimethylethyl ester, there was
obtained (3S)-3-amino-2-hydroxy-4-phenyl-N-(2,2,2-
trifluoroethyl)butanamide hydrochloride as a white solid.
M.p. 103.0-108.5°C
1H-NMRt300MHz,DMSO-d6) δ 2.71-2.85(m,1H),2.88-2.97(m,1H),
3.60-3.82(m,2.5H),3.91-4.05(m,1H),4.45(m,0.5H),6.75(d,0.5H,
J=5.7),6.98(d,0.5H,J=6.3),7.20-7.35(m, 5H),8.12 (brs,1.5H),
8.25(br s,1.5H),8.70(m,1H).

Reference Example 14
(3 S) - 3 - Amino - 2 - hy dr oxy -N- (2 -indany 1) - 4 - phenylbutanamide
hydrochloride
Following the reaction in an analogous manner to
Reference Example 8(5) and using 2-aminoindane in place of
aqueous ethylamine, there was obtained ((1S)-1-benzyl-3-
(2-indanylamino)-2-hydroxy-3-oxo-propyl)carbamic acid 1,1-
dimethylethyl ester as a white solid.
Following the reaction in an analogous manner to
Reference Example 8(6) and using ((1S)-1-benzyl-3-
(2-indanylamino)-2-hydroxy-3-oxopropyl)carbamic acid 1,1-
dimethylethyl ester in place of ((1S)-1-benzyl-3- ethylamino-
2-hydroxy-3-oxo- propyl)carbamic acid 1,1-dimethylethyl ester,
there was obtained (3S) -3-amino-2-hydroxy-N- (2-indanyl) -4-
phenylbutanamide hydrochloride as a white solid.
M.p. 183.0-184.8°C
1H-NMR(300MHz ,DMSO-d6) δ 2 . 76-2.96(m,4H),3.01-3.18(m,2H),
3.62(m,0.5H),3.74(m,0.5H),3.92(m,0.5H),4.25-4.39(m,1H),
4.49(m,0.5H),6.48(d,0.5H,J=5.7),6.72(d,0.5H,J=5.7),7.13-
7.35(m,9H),8.15(m,3.5H),8.26(d,0.5H,J=7.2).
Reference Example 15
(3S)-3-Amino-2-hydroxy-N- (2-methoxyethyl) - 4 -
phenylbutanamide hydrochloride
Following the reaction in an analogous manner to
Reference Example 8(5) and using methoxyethylamine in place of
aqueous ethylamine, there was obtained ((1S)-1-benzyl-2-
hydroxy-3-(2-methoxyethyl)-3-oxopropyl)carbamic acid 1,1-

dimethylethyl ester as a white solid.
Following the reaction in an analogous manner to
Reference Example 8(6) and using ((1S)-1-benzyl-2-
hydroxy-3-(2-methoxyethyl)-3-oxopropyl)carbamic acid 1,1-
dimethylethyl ester in place of ((1S)-1-benzyl-3-
ethylamino-2-hydroxy-3-oxopropyl)carbamic acid 1,1-
dimethylethyl ester, there was obtained ((3S)-3-amino-2-
hydroxy-N- ( 2-methoxyethyl) -4-phenylbutanamide hydrochloride
as a white solid.
M.p. 113.9-117.7°C
1H-NMR(300MHz ,DMSO-d6) δ 2.82(d, 1H, J=6.6 ),2.95 (m, 1H) , 3 .10-
3.19(m,2H),3.22(s,1.5H),3.23(s,1.5H),3.28-3.34(m,2H),3.57
(m,0.5H),3.70(m,0.5H),3.92(m,0.5H),4.32 (m,0.5H),6.59(d,
0.5H,J=4.5),6.87(d,0.5H,J=6.0),7.22-7.36(m,5H),7.92 t,0.5H,
J=5.7),7.98(t.0.5H,J=5.1),8.09(br s,1.5H),8.24(br s,1.5H).
Reference Example 16
(3S)-3-Amino-N-ethyl-2-hydroxy-5-phenylpentanamide
hydrochloride
(1) To a solution of Boc-1-homophenylalanine (20 g, 72
mmol) in dlmethoxyethane (100 mL) were added N-methylmorpholine
(7.2 g, 72 mmol) and isobutyl chloroformate (9.8 g, 72 mmol)
in an ice-salt bath. After 1 hour with stirring, the reaction
mixture was filtered and the filtrate was cooled in an ice-salt
bath, and a solution of NaBH4 (4.1 g, 107 mmol) in water (10
mL) was added, followed by water (300 mL) . The resultant
precipitates were collected by filtration, and the residue was
washed with water and methanol to give
N- (tert-butoxycarbonyl)-1-homo-phenylalaninol (15 g, 79%) as

colorless crystals.
(2) Following the reaction in an analogous manner to
Reference Example 8(2) and using N-(tert-butoxycarbonyl)-1-
homophenylalaninol in place of N- (tert-butoxycarbonyl)-
L-phenylalaninol, there was obtained N- (tert-butoxycarbonyl) -
L-phenylalaninal as a colorless oil.
(3) Following the reaction in an analogous manner to
Reference Example 8(3) and using N-(tert-butoxycarbonyl)-
L-homophenylalaninal in place of N- (tert-butoxycarbonyl)-
L-homophenylalaninal, there was obtained (3S)-3-amino-2-
hydroxy-5-phenylpentanoic acid as a white solid.
(4) Following the reaction in an analogous manner to
Reference Example 8(4) and using (3S)-3-amino-2-hydroxy-
5-phenylpentanoic acid in place of (3S)-3-amino-2-hydroxy-
4-phenylbutyric acid, there was obtained
(3S)-3-(tert-butoxycarbonylamino)-2-hydroxy-5-
phenylpentanoic acid as a colorless oil.
(5) Following the reaction in an analogous manner to
Reference Example 8(5) and using (3S)-3-(tert-
butoxycarbonylamino) -2-hydroxy-5-phenylpentanoic acid in
place of (3S)-3-(tert-butoxycarbonylamino)-2-hydroxy-4-
phenylbutanoic acid, there was obtained ((1S)-3-
ethylamino-2-hydroxy-3-oxo-1-(phenylethyl)propyl)carbamic
acid 1,1-dimethylethyl ester as a white solid.
(6) Following the reaction in an analogous manner.to
Reference Example 8(6) and using (1S)-3-ethylamino-2-
hydroxy-3-oxo-1-(phenylethyl)propyl)carbamic acid 1,1-
dimethylethyl ester in place of ((1S)-1-benzyl-3-
ethylamino-2-hydroxy-3-oxopropyl)carbamic acid 1,1-

dimethylethyl ester, there was obtained (3S) -3-amino-
N-ethyl-2-hydroxy-5-phenylpentanamide hydrochloride as a
white solid.
M.p. 134.4-134.9°C
1H-NMR(300 MHz ,DMSO-d6) δ 0 . 99-1. 06 (m, 3H) , 1. 65-1. 96 (m, 2H) ,
2.54-2.76(m,2H),3.07-3.23(m,2H),4.15(br s,0.5H),4.25(br s,
0.5H),6.44(br s,0.5H),6.55(br s,0.5H),7.17-7.33(m,5H).7.99
(br s,1.5H),8.15(t,1H,J=6.2),8.23(br s,1.5H).
Reference Example 17
(3S) -3-Amino-N-cyclopropyl-2-hydroxy-5~phenylpentanamide
hydrochloride
Following the reaction in an analogous manner to
Reference Example 16(5) and using cyclopropylamine in place of
aqueous ethylamine, there was obtained ((1S)-3-
cyclopropylamino-2-hydroxy-3-oxo-1-
(phenylethyl)propyl)carbamic acid 1,1-dimethylethyl ester as
a white solid.
Following the reaction in an analogous manner to
Reference Example 16(6) and using ((1S)-3-cyclopropylamino-
2-hydroxy-3-oxo-1-(phenylethyl)propyl)carbamic acid 1,1-
dimethylethyl ester in place of ((1S)-1-benzyl-3-ethylamino-
2-hydroxy-3-oxopropyl)carbamic acid 1,1-dimethylethyl ester,
there was obtained (3S)-3-amino-N-cyclopropyl-2-
hydroxy-5-phenylpentanamide hydrochloride as a white solid.
M.p. 140.2-141.3°C
1H-NMR(300MHz,DMSO-d6) δ 0.46-0.64(m,4H),1.64-1.99(m,2H) ,
2.54-2.78(m,3H),3.35(m,1H),4.13(br s,0.5H),4.26(br s,0.5H),
6.37(br s,0.5H),6.51(br s,0. 5H) , 7.17-7.33(m,5H),8.05(br s.

1.5H),8.15(d,0.5H,J=4.5 ) ,8.20(d,0.5H,J=4.8),8.27(br s,
1.5H).
Reference Example 18
(3S) -3-Amino-2-hydroxy-5-methyl-N-( 2-phenoxyethyl) -
hexanamide hydrochloride
(1) Following the reaction in an analogous manner to
Reference Example 8(1) and using L-leucinol in place of
L-phenylalaninol, there was obtained N- (tert-butoxycarbonyl) -
L-leucinol (70 g, 84 %) as a colorless oil.
(2) Following the reaction in an analogous manner to
Reference Example 8(2) and using N-(tert-butoxycarbonyl)-
L-leucinol in place of N-(tert-butoxycarbonyl)-1-
phenylalaninol, there was obtained N-(tert-butoxycarbonyl)-
L-leucinal as a colorless oil.

(3) Following the reaction in an analogous manner to
Reference Examples 8(3) and 8(4) and using N-(tert-
butoxycarbonyl)-1-leucinal in place of N-(tert-
butoxycarbonyl)-1-phenylalaninal, there was obtained (3S)-
3-(tert-butoxycarbonylamino)-2-hydroxy-5-methylhexanoic
acid as a colorless oil.
(4) Following the reaction in an analogous manner to
Reference Example 8(5) and using (3S)-3-(tert-
butoxycarbonylamino ) -2-hydroxy- 5 -methylhexanoic acid in
place of (3S)-3-(tert-butoxycarbonylamino)-2-hydroxy-
4-phenylbutanoic acid, and 2-phenoxcyethylamine in place of
aqueous ethylamine, there was obtained ((1S)-2-hydroxy-1-
(2-methylpropyl)-3-oxo-3-(2-phenoxyethyl)amino-
propyl)carbamic acid 1,1-dimethylethyl ester as a colorless

oil.
(5) Following the reaction in an analogous manner to
Reference Example 8(6) and using ((1S)-2-hydroxy-1-(2-
methylpropyl) - 3 - oxo - 3 - ( 2 -phenoxyethyl) aminopropy 1) carbamic
acid 1,1-dimethylethyl ester in place of ((1S)-1-benzyl-3-
ethylamino-2-hydroxy-3-oxopropyl) carbamic acid 1,1-
dimethylethyl ester, there was obtained the title compound as
a white solid.
M.p. 93.6-96.2°C
1H-NMR( 300MHz,DMSO-d6) δ 0 . 71-0 . 89 (m, 6H) , 1. 35-1. 47 (m, 2H) ,
1.72(m,1H),3.48-3.54(m,4H),4.00-4.07(m,2H),4.12(d,0.5H,J=
3.6) ,4.33(d,0.5H,J=1.8),6.91-6.96(m,3H),7.27-7.32(m,2H),
7.95(br s,1.5H),8.19-8.29(m,2.5H).
Reference Example 19
3-Amino-2-hydroxy-5-phenylpentanamide hydrochloride
Following the reaction in an analogous manner to
Reference Example 8(5) and using ammonia gas in place of aqueous
ethylamine, there was obtained l-benzyl-3-amino-2-hydroxy-
3-oxopropyl)carbamic acid 1,1-dimethylethyl ester as a white
solid.
Following the reaction in an analogous manner to
Reference Example 8(6) and using (1-benzyl-3-amiino—2-
hydroxy—3-oxopropyl)carbamic acid 1,1-dimethylethyl ester in
place of ((1S)~l-benzyl-3-ethylamino-2-hydroxy-3-oxo-
propyl)carbamic acid 1,1-dimethylethyl ester, there was
obtained the title compound as a white solid.
1H-NMR(300MHz,DMSO-d6) δ 2.82(m,1H),2.93(m,1H),3.61(m,1H),
3.85(m,0.5H),4.26(m,0.5H),6.48(d,0.5H,J=4.8),6.75(d,0.5H,

J=5.7),7.24-7.35(m,5H),7.52(m,2H),8.04(brs,1.5H),8.17(brs,
1.5H).
Reference Example 20
N-((2-(Pyridine-2-yl)ethyl)carbonyl)-1-leucine
N-hydroxysuccinimide ester
(1) Following the reaction in an analogous manner to
Reference Example 2(1) and using (2-pyridyl)ethanol in place
of (S)-3-hydroxytetrahydrofuran, there was obtained
N-succinimidyl 2-(pyridin-2-yl)ethylcarbonate as a brown oil.
(2) Following the reaction in an analogous manner to
Reference Example 2(2) and using N-succinimidyl
2-(pyridin-2-yl)ethylcarbonate in place of N-succinimidyl
(3S)-3-tetrahydrofuranyl carbonate, there was obtained
N-{ (2- (pyridin-2-yl)ethyloxy)carbonyl) -1-leucine ethyl ester
as a colorless oil.
(3) Following the reaction in an analogous manner to
Reference Example 2(3) and using N- ((2-(pyridin-2-
yl)ethyloxy)carbonyl)-1-leucine ethyl ester in place of
W-(((S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine ethyl
ester, there was obtained N-((2-(pyridin-2-
yl)ethyloxy)carbonyl)-1-leucine as a white solid.
(4) Following the reaction in an analogous manner to
Reference Example 1(2) and using N-((2-(pyridin-2-
yl)ethyloxy)carbonyl)-1-leucine in place of N-((2-
methoxyethoxy)carbonyl-L-leucine, there was obtained the
title compound as a colorless oil.
1H-NMR(300 MHz,DMSO-d6) δ 0 . 82-0 . 91(m, 6H) , 1. 42-1. 76 (m, 3H) ,
2. 76-2.81(m,4H),3.00-3.06 (m,2H),4.30-4.40(m,3H),7.23(dd,1H,

J=7.1,5.3),7.30(d,1H,J=7.8),7.71(m,1H),7.90 (d,1H,J=8.1),
8.50(d,1H,J=4.5).
Reference Example 21
N-((2-(6-Methylpyridin-2-yl)ethyloxy)carbonyl)-1-leucine
N-hydroxysuccinimide ester
(1) Following the reaction in an analogous manner to
Reference Example 2(1) and using
2-(6-methylpyridin-2-yl)ethanol in place of
(S)-3-hydroxytetrahydrofuran, there was obtained
N-succinimidyl 2-(6-methylpyridin-2-yl)ethylcarbonate as a
brown oil.
(2) Following the reaction in an analogous manner to
Reference Example 2(2) and using N-succinimidyl
2-(6-methylpyridin-2-yl)ethylcarbonate in place of
N-succinimidyl (3S)-3-tetrahydrofuranyl carbonate, there was
obtained N-((2-(6-methylpyridin-2-yl)ethyloxy)carbonyl)-1-
leucine ethyl ester as a colorless oil.
(3) Following the reaction in an analogous manner to
Reference Example 2(3) and using N- ((2-(6-methylpyridin-2-
yl)ethylbxy)carbonyl)-1-leucine ethyl ester in place of
N- (((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine ethyl
ester, there was obtained N-((2-(6-methylpyridin-2-
yl)ethyloxy)carbonyl)-1-leucine as a colorless oil.
(4) Following the reaction in an analogous manner to
Reference Example 1(2) and using
N-((2-(6-methylpyridin-2-yl)ethyloxy)carbonyl)-1-leucine in
place of N-((2-methoxyethoxy)carbonyl)-1-leucine, there was
obtained the title compound as a colorless oil.

1H-NMR (300 MHz, DMSO-d6) δ 0.83-0.92 (m, 6H) , 1.49-1.77 (m,
3H), 2.43 (s, 3H) , 2.81 (s, 4H) , 2.99 (t, 2H, J = 6.5), 4.29-4.42
(m, 3H), 7.07-7.09 (m, 2H) . 7.58 (t, 1H, J = 7.7), 7.91 (d, 1H,
J = 8.4) .
Reference Example 22
N-((2-(5-Ethylpyridin-2-yl)ethyloxy)carbonyl)-1-leucine
N-hydroxysuccinimide ester
(1) Following the reaction in an analogous manner to
Reference Example 2(1) and using (5-ethylpyridin-2-yl)ethanol
in place of (S)-3-hydroxytetrahydrofuran, there was obtained
N-succinimidyl 2-(5-ethylpyridin-2-yl)ethylcarbonate as a
brown oil.
(2) Following the reaction in an analogous manner to
Reference Example 2(2) and using N-succinimidyl
2-(5-ethylpyridin-2-yl)ethylcarbonate in place of
N-succinimidyl (3S)-3-tetrahydrofuranyl carbonate, there was
obtained N-((2-(5-ethylpyridin-2-yl)ethyloxy)carbonyl)-1-
leucine ethyl ester as a colorless oil.
(3) Following the reaction in an analogous manner to
Reference Example 2(3) and using
N-(((2-(5-ethylpyridin-2-yl)ethyloxy)carbonyl)-1-leucine
ethyl ester in place of N-(((3S)-tetrahydrofuran-3-
yloxy)carbonyl)-1-leucine ethyl ester, there was obtained
N-((2-(5-ethylpyridin-2-yl)ethyloxy)carbonyl)-1-leucine as a
colorless oil.
(4) Following the reaction in an analogous manner to
Reference Example 1(2) and using N- ((2-(5-ethylpyridin-2-
yl)ethyloxy)carbonyl)-1-leucine in place of N-((2-

methoxyethoxy)carbonyl)-1-leucine, there was obtained the
title compound, as a colorless oil.
1H-NMR (300 MHz, DMSO-d6) δ 0.75-0.92 (m, 6H) , 1.12-1.25 (m,
3H), 1.36-1.72 (m, 3H), 2.54-2.63 (m, 2H), 2.81-2.83 (m, 4H) ,
2.96-3.02 (m, 2H), 4.04 (m, 1H), 4.29-4.37 (m, 2H) , 7.21 (d,
1H, J = 7.8), 7.53 (m, 1H) , 7.90 (d, 1H, J = 7.8) , 8.34 (m, 1H) .
Reference Example 23
N-((2-tert-Butoxyethyloxy)carbonyl)-1-leucine
N-hydroxysuccinimide ester
(1) Following the reaction in an analogous manner to
Reference Example 2(1) and using ethylene glycol tert-butyl
ether in place of (S)-3-hydroxytetrahydrofuran, there was
obtained N-succinimidyl 2-tert-butoxyethyl carbonate as a
colorless oil.
(2) Following the reaction in an analogous manner to
Reference Example 2(2) and using N-succinimidyl
2-tert-butoxyethyl carbonate in place of N-succinimidyl
(3S)-3-tetrahydrofuranyl carbonate, there was obtained
N-((2-tert-butoxyethyloxy)carbonyl)-1-leucine ethyl ester as
a colorless oil.
(3) Following the reaction in an analogous manner to
Reference Example 2(3) and using N-((2-tert-
butoxye thyloxy) carbonyl)-1-leucine ethyl ester in place of
N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl)-1-leucine ethyl
ester, there was obtained N-((2-tert-
butoxye thyloxy) carbonyl) -1-leucine as a colorless oil.
(4) Following the reaction in an analogous manner to
Reference Example 1(2) and using

N-((2-tert-butoxyethyloxy) carbonyl) -1-leucine in place of
N-((2-methoxyethyloxy)carbonyl)-1-leucine, there was
obtained the title compound as a colorless oil.
1H-NMR(300 MHz, DMSO-d6) δ 0.89 (d, 3H, J = 6.3), 0.92 (d, 3H,
J = 6.3), 1.13 (s, 9H), 1.61 (m, 1H), 1.74 (m, 2H), 2.81 (s,
4H), 3.48 (t, 2H, J = 4.7), 4.04 (m, 2H), 4.40 (m, 1H), 8.00
(d, 1H, J = 7.8).
Reference Example 24
N-((2-Isopropoxyethyloxy)carbonyl)-1-leucine
N-hydroxysuccinimide ester
(1) Following the reaction in an analogous manner to
Reference Example 2(1) and using ethylene glycol isopropyl
ether in place of (S)-3-hydroxytetrahydrofuran, there was
obtained N-succinimidyl 2-isopropoxyethyl carbonate as a
colorless oil.
(2) Following the reaction in an analogous manner to
Reference Example 2(2) and using N-succinimidyl
2-isopropoxyethyl carbonate in place of N-succinimidyl
(3S)-3-tetrahydrofuranyl carbonate, there was obtained
N-((2-isopropoxyethyloxy) carbonyl)-1-leucine ethyl ester as a
colorless oil.
(3) Following the reaction in an analogous manner to
Reference Example 2(3) and using
N-((2-isopropoxyethyloxy)carbonyl)-1-leucine ethyl ester in
place of N-(((3S)-tetrahydrofuran-3-yloxy)carbonyl)-
L-leucine ethyl ester, there was obtained
N-((2-isopropoxyethyloxy)carbonyl)-1-leucine as a colorless
oil.

(4) Following the reaction in an analogous manner to
Reference Example 1(2) and using N-{{2-
isopropoxyethyloxy)carbonyl)-1-leucine in place of N-{{2-
methoxyethyloxy)carbonyl)-1-leucine, there was obtained the
title compound as a colorless oil.
1H-NMR (300 MHz, DMSO-d6) δ 0.89 (d, 3H, J = 6.6) , 0.92 (d, 3H,
J = 6.3), 1.08 (d, 6H, J = 6.3), 1.61 (m, 1H), 1.74 (m, 2H),
2.81 (s, 4H), 3.53 (m, 2H), 3.57 (m, 1H), 4.07 (m, 2H), 4.40
(m, 1H), 8.02 (d, 1H, J = 7.8).
Example 1
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-
(ethylamino)propyl)amino)carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 1)

To a solution of the compound of Reference Example 1(1.2
g, 3.6 mmol) and the compound of Reference Example 8 (1.0 g,
4.0 mmol) in DMF was added triethylamine (1.1 g, 11 mmol, 1.5
mL) . The mixture was stirred at room temperature for 18 hours,
and concentrated in vacuo. The residue was dissolved in ethyl
acetate (EtOAc), and the solution was washed with 1M HCl,
saturated aqueous NaHCO3 and saturated aqueous NaCl, dried over
anhydrous MgSO4, and concentrated in vacuo. The resulting
white solid was washed with a mixture of EtOAc and hexane (1 :

9) to give ((1S) -1- ((( (1S) -1-benzyl-3-ethylamino-2-hydroxy-
3-oxopropyl)amino)carbonyl) -3-methylbutyl)carbamic acid.
2-methoxyethyl ester (0.75 g, 47%) as a white solid.
To a solution of ((1S)-1-((((1S)-1-benzyl-3-ethylamino-
2-hydroxy-3-oxo-propyl)amino)carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester (0.7 g, 1.6
mmol) in CH2Cl2 (70 mL) was added Dess-Martin periodinane (1.0
g, 2.4 mmol) . The mixture was stirred at room temperature for
18 hours. Aqueous 10% Na2S203 (35 mL) and saturated aqueous
NaHCO3 (35 mL) were added thereto, and the mixture was stirrer
at room temperature for 30 minutes. The organic layer was
separated, washed with 1M HCl, saturated aqueous NaHCO3 and
saturated aqueous NaCl, dried over MgSO4, and concentrated in
vacuo. The residue was crystallized from EtOAc/hexane to give
the title compound (0.62 g, 88%) as colorless crystals. M.p.
138.0-138.3°C.
1H-NMR(300 MHz, DMSO-d6) δ 0 . 83(d,3H,J=7.5),0.85(d,3H,J=7.2)
1.04(t,3H,J=7.1),1.35(m,2H),1.56(m,1H),2.82(m,1H),3.14(m,
3H),3.25(s,3H),3.47(t,2H,J=4.5),4.04(m,3H),5.19(m,1H),
7.16-7.33(m,6H),8.24(d,1H,J=7.2),8.70(m,1H).
MALDI-TOF-MS calcd for C22H33N3O6 (M+Na) + , 458.2267, Fount
458.2361.
Example 2
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-
(ethylamino)propyl)amino)carbonyl)-3-methylbutyl)carbamic
acid (3S)-tetrahydrofuran-3-yl ester (Compound 2)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 2 in place of
the compound of Reference Example 1, there was obtained the
title compound as colorless crystals, via ((1S)-1-((((1S)-1-
benzyl- 3 -ethylamiino—2 -hydroxy- 3 -oxopropyl) amino) carbonyl) -
3-methylbutyl)carbamic acid (3S)-tetrahydrofuran-3-yl ester.
M.p. 158.9-160.7°C
1H-NMR(300MHz,DMSO-d6) δ 0.83(d,3H,J=6.6),0.85(d,3H,J=6.9),
1.04(t,3H,J=7.1),1.35(m,2H),1.55(m,1H),1.83(m,1H),2.08(m,
1H),2.82(m,1H),3.14(m,3H),3.61-3.78(m,4H),4.01(m,1H),5.07
(m,1H),5.19(m,1H),7.17-7.33(m,6H),8.22(d,1H,J=7.2),8.69(t,
1H,J=5.7).
MALDI-TOF-MS:C23H33N3O6(M+H)+ , 448.2447, Found: 448 .2509 .
Example 3
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-
(ethylamino) propyl) amino) carbonyl) - 3 -methylbutyl) carbamic
acid tetrahydro-4H-pyran-4-yl ester (Compound 3)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 3 in place of the
compound of Reference Example 1, there was obtained the title
compound as colorless crystals, via ((1S)-1-((((1S)-1-
benzyl- 3 -ethylamino - 2 -hydroxy- 3 -oxopropyl) amino) carbonyl) -
3-methylbutyl)carbamic acid tetrahydro-4H-pyran-4-yl ester.
M.p. 140.0-141.8°C
1H-NMR(300MHz,DMSO-d6) δ 0.84(m,6H),1.04(t,3H,J=7.2),1.35 (m,
2H),1.49(m,3H),1.79(m,2H),2.82 (m,1H),3.14(m,3H),3.41(m,2H),
3.78(m,2H),4.02(m,1H) ,4.66(m,1H),5.19(m,1H),7.15-7.33(m,
6H),8.22(d,1H,J=7.2), 8.69(t,1H,J=5.7).
MALDI-TOF-MS:C24H35N3O6(M+Na)+ , 484.2424, Found: 484.2486.
Example 4
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-
(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 4)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 9 in place of the
compound of Reference Example 8, there was obtained the title
compound as colorless crystals, via
( (1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy-
3-oxo-propyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-methoxyethyl ester.
M.p. 112.4-113.5°C
1H-NMR(300MHz,DMSO-d6) δ 0 . 58(m, 2H) , 0 . 65 (m, 2H) , 0 . 83 (d, 3H,
J=6.6),0.85(d,3H,3=6.6),1.35(m,2H),1.56(m,1H),2.68-2.88
(m,2H),3.11(m,1H),3.25(s,3H),3.47(t,2H,J=4.5),4.04(m,3H),
5.l7(m,1H),7.17-7.34(m,6H),8.25(dr1H,J=7.2),8.73(d,1H,
J=4.8).
MALDI-TOF-MS:C23H33N306(M+Na) + , 470 . 2267 , Found: 470 . 2441.
[α]D25+6.3° (c0.20,DMSO)
Example 5
((1S)-1-((((1S)-1-Benzyl-3-(cyclopropylamino)-2,3-dioxo-
propyl)amino)carbonyl)-3-methylbutyl)carbamic acid (3S)-
tetrahydrofuran-3-yl ester (Compound 5)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 2 in place of the
compound of Reference Example 1, and the compound of Reference

Example 9 in place of the compound of Reference Example 8, there
was obtained the title compound as colorless crystals, via
((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy-3-
oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
(3S)-tetrahydrofuran-3-yl ester.
M.p. 169.2-170.5°C
1H-NMR(300MHz,DMSO-d6) δ 0.58(m,2H),0.65(m,2H),0.83(d,3H,
J=8.1),0.85(d,3H,J=6.9),1.34(m,2H),1.55(m,1H),1.83(m,1H),
2.08(m,1H),2.79(m,2H),3.12(m,1H),3.61-3.80(m,4H),4.02 (m,
1H),5.08(m,1H),5.17(m,1H),7.22-7.35(m,6H),8.24(d,1H,J=6.6),
8.74(d,1H,J=5.1).
MALDI-TOF-MS:C24H33N3O6(M+Na)+, 482.2267, Found: 482.2586.
Example 6
((1S)-1-((((1S)-1-Benzyl-3-cyclopropylamino-2,3-
dioxo-propyl)amino)carbonyl)-3-methylbutyl)carbamic acid
tetrahydro-4H-pyran-4-yl ester (Compound 6)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 3 in place of the
compound of Reference Example 1, and the compound of Reference
Example 9 in place of the compound of Reference Example 8, there
was obtained the title compound as colorless crystals, via
((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy-3-

oxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid
tetrahydro-4H-pyran-4-yl ester.
M.p. 137.0-138.2°C
1H-NMRt 300MHz, DMSO-d6) 6 0 . 58 (m, 2H) , 0 . 65 (m, 2H) , 0 . 84(m, 6H) .
1.35(ra 2H) ,1.48(m,3H),1.80(m,2H),2.79(m,2H),3.11(m,1H),3.41
(m,2H),3.79(m,2H),4.03(m,1H),4.65(m,1H),5.18(m,1H),7.15-
7.30(m,6H) ,8.23(d,1H,J=6.9),8.73(d,1H,J=5.4).
MALDI-TOF-MS:C25H35N306(M+H)+ , 474.2604, Found: 474.2643.
Example 7
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-
( propylamino) propyl) amino) carbonyl) - 3 -methylbutyl) carbamic
acid 2-methoxyethyl ester (Compound 7)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 10 in place of
the compound of Reference Example 8, there was obtained the
title compound as colorless crystals, via ((1S)-1-((((1S)-
1-benzyl-2-hydroxy-3-oxo-3-
(propylamino)propyl) amino)carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester.
M.p.l08.8-109.9°C
1H-NMR(30 MHz,DMS0-d6) δ 0.83(m,9H),1.35(m,2H),1.46(m,2H),
1.55(m,1H),2.83(dd,1H,J=14.0,9.2),3.08(m,3H),3.25(s,3H),

3.48(t,2H,J=4.4),4.04(m,3H),5.19(m,1H),7.22-7.28(m,6H),
8.24(d,1H,J=6.9),8.68(t,1H,J=5.6).
MALDI-TOF-MS:C23H35N3O6(M+H) + , 450.2604, Found: 450.2832.
Example 8
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-
(cyclobutylamino) propyl) amino) carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 8)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 11 in place of
the compound of Reference Example 8, there was obtained the
title compound as colorless crystals, via
((1S)-1-((((1S)-1-benzyl-3-cyclobutylamino-2-hydroxy-3-
oxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid
2-methoxyethyl ester.
M.p. 114.2-115.3°C
1H-NMR(300MHz,DMSO-d6) δ 0.84(m, 6H),1.34(m,2H),1.49-1.72(m,
3H),2.10(m,4H),2.81(dd,1H,J=13.8,9.3),3.10(m,1H),3.25(s,
3H),3.47(m,2H),4.03(m,3H),4.22(m,1H),5.15(m,1H),7.24(m,6H),
8.24(d,1H,J=7.2),8.91(d,1H,J=7.8).
MALDI-TOF-MS:C24H35N3O6(M+Na)+ , 484.2424, Found: 484.2400.
Example 9

((1S)-1-((((1S)-1-Benzyl-3-butylamino-2,3-dioxo-
propyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-methoxyethyl ester (Compound 9)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 12 in place of
the compound of Reference Example 8, there was obtained the
title compound as colorless crystals, via ((1S)-1-((((1S)-
1-benzyl-3-butylamino-2 -hydroxy- 3 -oxopropyl) amino) carbonyl)
-3-methylbutyl)carbamic acid 2-methoxyethyl ester.
M.p. 94.0-95.2°C
1H-NMR(300MHz,DMSO-d6) δ 0.85(m,9H),1.25(m,2H),1.35(m,2H),
1.42(m,2H),1.56(m,1H),2.83(dd,1H,J=13.8,9.0),3.10(m,3H),
3.25(s,3H),3.47(t,2H,J=4.5),4.04(m,3H),5.l8(m,1H),7.21-
7.29(m,6H),8.23(d,1H,J=6.6),8.67(t,1H,J=6.0).
MALDI-TOF-MS:C24H37N3O6(M+H)+ , 464.2760, Found: 464 . 2870 .
Example 10
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-(2,2,2-
trifluoroethylamino)propyl)amino)carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 10)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 13 in place of
the compound of Reference Example 8, there was obtained the
title compound as colorless crystals, via
((1S)-1-((((1S)-1-benzyl-2-hydroxy-3-oxo-3-(2,2,2-
trifluoroethyl-amino)propyl)amino)carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester.
M.p. 152.5-153.9°C
1H-NMR(300MHz, DMSO-d6) δ 0.84(m,6H),1.34(m,2H),1.55(m,1H),
2.86(dd,1H,J=14.0,8.6),3.10(dd,1H,J=14.1,4.8),3.25(s,3H),
3.48(t,2H,J=4.7),3.90(m,2H),4.04(m,3H),5.14(m,1H),7.21-
7.31(m,6H),8.34(d,1H,J=6.9),9.29(m,1H).
MALDI-TOF-MS:C22H3oF3N3O6(M+H)+ , 490.2165, Found: 490.2434.
Example 11
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-(2-
indanylamino)propyl)amino)carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 11)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 14 in place of
the compound of Reference Example 8, there was obtained the
title compound as colorless crystals, via ((1S)-1-((((1S)-
1-benzyl-2-hydroxy-3-(2-indanylamino)-3-
oxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid
2-methoxyethyl ester.
M.p. 141.9-143.5°C
1H-NMR(300MHz,DMSO-d6) δ 0.83(d,3H,J=6.9),0.86(d,3H,J=6.9),
1.36(m,2H),1.57(m,1H),2.80-2.96(m,3H),3.10-3.18(m,3H),3.24
(s,3H),3.47(t,2H,J=4.7),4.04(m,3H),4.50(m,1H),5.19(m,1H),
7.13-7.30(m,10H),8.29(d,1H,J=6.9),8.97(d,1H,J=7.2).
MALDI-TOF-MS:C29H37N3O6(M+H) + , 524.2760, Found: 524.2810.0
Example 12
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-(2-
methoxyethylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 12)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 15 in place of
the compound of Reference Example 8, the title compound was
obtained as colorless crystals, via ((1S)-1-((((1S)-1-benzyl-
2-hydroxy-3- (2-methoxyethylamino) -3-oxopropyl)amino)carbonyl)

-3-methylbutyl)carbamic acid 2-methoxyethyl ester
M.p. 127.0-127.9°C
1H-NMR(300MHz,DMSO-d6) δ 0.83(d,3H,J=6.9),0.86(d,3.J=6.9),
1.35(m,2H),1.56(m,1H),2.83(dd,1H,J=13.8,9.0),3.11(dd,1H,J=l
4.0,4.4),3.24(s,3H),3.25(s,3H),3.16-3.34(m,2H),3.39(m, 2H),3
.48(t,2H,J=4.5),4.04(m,3H),5.20(m,1H),7.18-7.30(m,6H),8.21(
d,1H,J=6.9),8.66(t,1H,J=5.4).
MALDI-TOF-MS :C23H35N3O7(M+Na) + , 488 . 2373 , Found: 488 . 2680 .
Example 13
((1S)-1-((((1S)-2,3-Dioxo-3-ethylamino-1-
(phenylethyl)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 13)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 16 in place of
the compound of Reference Example 8, the title compound was
obtained as colorless crystals, via ((1S)-1-((((1S)-3-
ethylamino-2-hydroxy-3-oxo-1-
(phenylethyl)propyl)amino)carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester.
M.p. 119.1-120.4°C
1H-NMR( 300MHz,DMSO-d6) δ 0.89(t,6H,J=6.3),1.03(t,3H,J=7.2) ,

1.43(t,2H,J=7.2).1.61-1.85(m,2H),2.07(m,1H),2.56-2.74
(m,2H),3.07-3.17(m,2H),3.25(s,3H),3.49(t,2H,J=4.7),4.05-
4.14(m,3H),4.89(m,1H),7.16-7.36(m,5H),7.34(d,1H,J=8.4),
8.33(d,1H,J=6.9),8.65(t,1H,J=5.9).
MALDI-TOF-MS:C23H35N3O6(M+H)+, 450 . 2604 ,Found: 450. 2701.
Example 14
((1S)-1-((((1S)-2,3-Dioxo-3-ethylamino-1-
(phenylethyl)propyl)amino)carbonyl)-3-
methylbutyl) carbamic acid (3S)-tetrahydrofuran-3-yl ester
(Compound 14)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 2 and 16 in place
of the compounds of Reference Examples 1 and 8 respectively,
the title compound was obtained as colorless crystals, via
((1S)-1-((((1S)-3-ethylamino-2-hydroxy-3-oxo-1-
(phenylethyl)propyl)amino)carbonyl)-3-methylbutyl)carbamic
acid (3S)-tetrahydrofuran-3-yl ester.
M.p. 111.9-114.5°C
1H-NMR(300MHz,DMSO-d6) δ 0 . 89 (t, 6H , J=6 . 3) , 1. 03 (t, 3H, J=7.2),
1.43(t,2H,J=7.4),1.60-1.91(m,3H),2.09(m,2H),2.56-2.76(m,
2H),3.07-3.17(m,2H),3.63-3.82(m,4H),4.02-4.13(m,1H),4.88

(m,1H), 5.09-5.13(m,1H),7.16-7.31(m,5H),7.34(d,1H,J=8.4),8.3
4(d,1H,J=6.9),8.66(t,1H,J=5.7).
MALDI-TOF-MS:C24H35N3O6(M+H) + , 462. 2604,Found: 462. 2870.
Example 15
((1S)-1-((((1S)-2,3-Dioxo-3-cyclopropylamino-1-
(phenylethyl) propyl) amino) carbonyl) - 3 -methylbutyl} carbamic
acid 2-methoxyethyl ester (Compound 15)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Example 17 in place of
the compound of Reference Example 8, the title compound was
obtained as colorless crystals, via ((1S)-1-((((1S)-3-
cyclopropylamino-2-hydroxy-3-oxo-1-
(phenylethyl)propyl)amino)carbonyl)-3-methylbutyl)carbamic
acid 2-methoxyethyl ester
M.p. 109.7-111.1°C
1H-NMR(300MHz,DMSO-d6) δ 0.53-0.68(m, 4H),0.87-0.91(m,6H),
1.43(t,3H,J=7.2),1.59-1.85(m,2H),2.01-2.13(m,1H),2.56-2.74
(m,3H),3.25(s,3H),3.48-3.51(m,2H),4.05-4.14(m,3H),4.87(m,lH
),7.17-7.36(m,6H),8.34(d,1H,J=6.6),8.69(d,1H,J=5.1).
MALDI-TOF-MS:C24H35N3O6(M+H)+ , 462. 2604, Found :462.2742.

Example 16
((1S)-1-((((1S)-2,3-Dioxo-3-cyclopropylamino-1-
(phenylethyl)propyl)amino)carbonyl) - 3 -
methylbutyl)carbamic acid (3S)-tetrahydro-furan-3-yl ester
(Compound 16)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 2 and 17 in
place of the compounds of Reference Examples 1 and 8
respectively, the title compound was obtained as colorless
crystals, via ((1S)-1-((((1S)-3-cyclopropylamino-2-hydroxy-
3-oxo-1-(phenylethyl)propyl)amino)carbonyl) - 3 -
methylbutyl)carbamic acid (3S)-tetrahydrofuran-3-yl ester.
M.p. 115.8-116.2°C
1H-NMR(300MHzDMSO-d6) δ 0.56-0.59(m,4H),0.88(t,6H,J=6.3),
1.42(t,2H,J=7.4),1.60-1.91(m,3H),2.09(m,2H),2.56-2.76(m,
3H),3.63-3.81(m,4H),4.05-4.13(m,1H),4.87(m,1H),5.09-5.13(m,
1H),7.20-7.35(m,6H),8.34(d,1H,J=6.9),8.69(d,1H,J=5.1).
MALDI-TOF-MS:C25H35N3O6(M+H) + , 474. 2604,Found: 474 . 2598 .
Example 17
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-
(cyclopropylamino)propyl)amino)carbonyl)-3-

methylbutyl)carbamic acid 5-methoxy-3-oxapentyl ester
(Compound 17)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 4 and 9 in place
of the compounds of Reference Examples 1 and 8 respectively,
the title compound was obtained as colorless crystals, via
((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy-3-
oxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid
5-methoxy-3-oxapentyl ester.
M.p. 127.9-128.7°C
1H-NMR(300MHzDMSO-d6) δ 0 . 54-0 . 66 (m, 4H) , 0 . 81-0 . 86 (m, 6H) ,
1.30-1-42(m,2H),1.57(m, 1H),2.73(m,1H),2.82(dd,1H,J=14.3,
9.2),3.11(dd,1H,J=13.8,4.2),3.24(s,3H),3.42-3.44(m,2H),
3.50-3.57(m,4H),3.99-4.04(m,3H),5.17(m,1H),7.22-7.30(m,6H) ,
8.22(d,1H,J=6.9),8.71(d,1H,J=4.8).
MALDI-TOF-MS :C25H37N3O7(M+Na) + , 514 . 2530 .Found: 514 . 2944 .
[α]D25+13.9° (c 0.20,DMSO)
Example 18
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-
(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 8-methoxy-3,6-dioxaoctyl ester
(Compound 18)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 5 and 9 in place
of the compounds of Reference Examples 1 and 8 respectively,
the title compound was obtained as colorless crystals, via
((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy-3-
oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
8-methoxy-3,6-dioxaoctyl ester.
M.p. 116.0-117.2°C.
1H-NMR(300MHz,DMSO-d6) δ 0 . 58 (m, 2H) , 0 . 65 (m, 2H) , 0 . 83 (d, 3H,
J=7.8),0.85(d,3H,J=6.9),1.35(m,2H),1.57(m,1H),2.73-2.86
(m,2H) ,3.11(m,1H),3.24(s,3H),3.44(m,2H),3.51(m,6H),3.56(t,2
H, J=4.7),4.04(m,3H),5.17(m,1H),7.22-7.31(m,6H),8.25(d,1H,J=
6.9),8.73(d,1H,J=5.1).
MALDI-TOF-MS:C27H4iN3O8(M+Na) +, 558 . 2792 ,Found: 558 .2111.
[α]D25+2.5° (c 0.20.DMSO)
Example 19
((1S)-1-((((1S)-1-Benzyl-2,3-dioxo-3-
(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 111-methoxy-3 , 6 , 9-trioxaundecanyl
ester (Compound 19)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 6 and 9 in place
of the compounds of Reference Examples 1 and 8 respectively,
the title compound was obtained as colorless crystals, via
((1S)-1-((((1S)-1-benzyl-3-cyclopropylamino-2-hydroxy-3-
oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
111-methoxy-3,6,9-trioxaundecanyl ester.
M.p. 97.5-98.5°C
1H-NMR(300MHz,DMSO-d6) δ 0.54-0.66(m,4H),0.81-0.86(m,6H),
1.32-1.37(m,2H),1.56(m,1H),2.73(m,1H),2.82(dd,1H,J=14.0,9.2
),3.11(dd,1H,J=14.1,4.2),3.24(s,3H),3.41-3.44(m.2H),3.50-3.
51(m,10H),3.54-3.57(m,2H),3.99-4.08(m,3H),5.16(m,1H),7.22-7
.31(m,6H),8.25(d,1H,J=7.2),8.73(d,1H,J=5.1).
MALDI-TOF-MS :C29H45N3O9(M+Na) + , 602 . 3054 .Found: 602 . 3427 .
[α]D25+6.9° (c 0.20,DMSO)
Example 20
((1S)-1-((((lS}-1-Benzyl-2,3-dioxo-3-
(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 14-methoxy-3,6,9,12-tetraoxa-
tetradecanyl ester (Compound 20)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 7 and 9 in place
of the compounds of Reference Examples 1 and 7 respectively,
the title compound was obtained as colorless crystals, via
( (IS) -1- ( ( ( (,lS)-1-benzyl-3-cyclopropylamino-2-hydroxy-3-
oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
14-methoxy-3,6,9,12-tetraoxatetradecanyl ester.
M.p. 98.5-99.9°C
1H-NMR(300MHz,DMSO-d6) δ 0.58(m,2H),0.65(m,2H),0.83 (d,3H,
J=6.9),0.85(d,3H,J=7.8),1.35(m,2H),1.57(m,1H),2.73-2.86
(m,2H),3.11(m,1H),3.24(s,3H),3.42(m,2H),3.51(m,14H),3.56
(t.2H,J=3.3),4.04(m,3H),5.17(m,1H),7.22-7.30(m,6H),8.24( d, 1
H,J=6.9),8.72(d,1H,J=4.5).
MALDI-TOF-MS:C31H49N3O10(M+Na)+ , 646 . 3316 ,Found: 646 . 3404 .
Example 21
((1S)-1-((((1S)-2,3-Dioxo-1-(2-methylpropyl)-3-(2-
phenoxyethyl)aminopropyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 2-methoxyethyl ester (Compound 21)

Following the reaction in an analogous manner to Example
1 and using the compound of Reference Examples 18 in place of
the compound of Reference Example 8, the title compound was
obtained as colorless crystals, via ((1S)-1-((((1S)-2-
hydroxy-1- ( 2-methylpropyl) -3-oxo-3- (2-
phenoxyethyl) aminopropyl) amino) carbonyl) - 3 -
methylbutyl)carbamic acid 2-methoxyethyl ester.
M.p. 99.7-100.5°C
1H-NMR(300MHz,DMS0-d6) δ 0.88(dd,12H,J=12.0,6.3),1.35-1.54
(m,4H),1.58-1.75(m,2H),3.25(s,3H),3.46-3.53 (m, 4H) ,4.03-4.07
(m,5H),5.06(m,1H),6.91-6.95(m,3H),7.26-7.31(m,3H),8.15(d,lH
,J=7.2),8.81(t,1H,J=5.9).
MALDI-TOF-MS :C25H39N3O7(M+H)+ , 494 . 2866 , Found: 494 . 2967 .
Example 22
((1S)-1-("( ((1S)-2,3-Dioxo-1-(2-methylpropyl)-3-(2-
phenoxyethyl)aminopropyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 5-methoxy-3-oxapentyl ester
(Compound 22)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 4 and 18 in place
of the compounds of Reference Examples 1 and 8 respectively,
the title compound was obtained as colorless crystals, via
((1S)-!-((((1S)-2-hydroxy-1-(2-methylpropyl)-3-oxo-3-(2-
phenoxyethyl)aminopropyl)amino)carbonyl) - 3 -
methylbutyl)carbamic acid 5-methoxy-3-oxapentyl ester.
M.p. 53.5-54.1°C
1H-NMR(300MHz,DMSO-d6) δ 0.87(dd,12H,J=12.2,6.5),1.35-1.54
(m,4H),1.58-1.75(m,2H),3.24(s,3H),3.41-3.45(m,2H),3.47-3.57
(m,6H),4.03-4.07(m,5H),5.06(m,1H),6.91-6.96(m,3H),7.26-7.31
(m,3H),8.17(d,1H,J=6.9),8.83(t,1H,J=5.7).
MALDI-TOF-MS :C27H43N3O8(M+H) + , 538 . 3128 , Found: 538 . 3140 .
Example 23
((1S)-1-((((lRS)-3-amino-1-benzyl-2,3-
dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
5-methoxy-3-oxapentyl ester (Compound 23)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 4 and 19 in place
of the compounds of Reference Examples 1 and 8 respectively,
the title compound was obtained as colorless crystals, via
((1S)-1-((((lRS)-3-amino-1-benzyl-2-hydroxy-3-oxo-

propyl)amino)carbonyl)-3-methylbutyl)carbamic acid 5-
methoxy-3-oxapentyl ester.
1H-NMR(300MHz,DMSO-d6) δ0 . 77(d,3H,J=6.3),0.83(d,1.5H,J=6.6),
0.86(d,1.5H,J=6.9),1.05-1.63(m,3H),2.68-2.85(m,1H),3.12(m,l
H),3.23(s,3H),3.42(m,2H),3.51-3.56(m,4H),4.03(m,3H),5.22(m,
1H),7.21-7.31(m,6H),7.81(d,1H,J=14),8.06(d,1H,J=18),8.19(d,
0.5H,J=6.9),8.26(d,0.5H,J=7.5).
Example 24
((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2,3-dioxo-
propyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-(pyridin-2-yl)ethyl ester (Compound 24)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 20 and 9 in place
of the compounds of Reference Examples 1 and 8 respectively,
the title compound was obtained as colorless crystals, via
((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2-hydroxy-3-
oxopropyl)amino)carbonyl)-3-methylbutyl}carbamic acid
2-(pyridin-2-yl)ethyl ester.
1H-NMR(300MHz,DMSO-d6) δ 0.58-0.66(m,4H),0.83(t,6H,J=7.1),
1.31-1.35(m,2H),1.53(m,1H),2.74(m,1H).2.81(dd,1H,J=14.1,9.3
),3.02(t,2H,J=6.3),3.11(dd,1H,J=14.0,4.1),4.01(m,1H),4.28-4
.32(m,2H),5.17(m,1H),7.14-7.34(m,8H),7.75(t,1H,J=6.8),8.23{
d,1H,J= 7.2),8.51(d,1H,J=4.2),8.71(d,1H,J=4.5).

Example 25
( (1S)-1-((((1S)-1-Benzyl-3-(cyclopropylamino)-2,3-
dioxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid
2-(6-methylpyridin-2-yl)ethyl ester (Compound 25)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 21 and 9 in place
of the compounds of Reference Examples 1 and 8 respectively,
the title compound was obtained as colorless crystals, via
( ((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2-hydroxy-3-
oxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid
2-(6-methylpyridin-2-yl)ethyl ester.
M.p. 162.0-163.6°C
1H-NMR (300 MHz, DMSO-d6) δ 0.54-0.66 (m, 4H) , 0.76-0.86' (m,
6H), 1.54 (m, 1H), 2.43 (s, 3H), 2.73-2.86 (m, 2H), 2.96 (t,
2H, J = 6.5), 3.11 (m, 1H), 4.03 (m, 1H), 4.21-4.34 (m, 2H),
5.17 (m, 1H), 7.07-7.30 (m, 8H), 7.58 (t, 1H, J = 7.7), 8.23
(d, 1H, J = 6.9), 8.72 (d, 1H, J = 4.8).
Example 26
((1S)-1-((((1S)-1-Benzyl-3-(cyclopropylamino)-2,3-
dioxopropyl) amino) carbonyl) - 3 -methylbutyl) carbamic acid
2-(5-ethylpyridin-2-yl)ethyl ester (Compound 26)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 22 and 9 in place
of the compounds of Reference Examples 1 and 8 respectively,
the title compound was obtained as colorless crystals, via
((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2-hydroxy-3-o
xopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-(5-ethylpyridin-2-yl)ethyl ester.
M.p. 119. 9-121. 0°C
1H-NMR (300 MHz, DMS0-d6) δ 0.58-0.66 (m, 4H) , 0.75-0.85 (m, 6H) ,
1.17 (t, 3H, J = 7.7), 1.33-1.36 (m, 2H), 1.53 (m, 1H), 2.58
(dd, 2H, J = 15.5, 8.3), 2.74-2.85 (m, 2H) , 2.94-2.98 (m, 2H) ,
3.12 (m, 1H), 4.04 (m, 1H), 4.28-4.29 (m, 2H), 5.17 (m, 1H),
7.13-7.26 (m, 7H), 7.55 (d, 1H, J = 8.1), 8.22-8.35 (m, 2H) ,
8.75 (m, 1H).
Example 27
((1S)-1-((((1S)-1-Benzyl-3-(cyclopropylamino)-2,3-
dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-tert-butoxyethyl ester (Compound 27)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 23 and 9 in place
of the compounds of Reference Examples 1 and 8 respectively,
the title compound was obtained as colorless crystals, via
((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2-hydroxy-3-
oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-tert-butoxyethyl ester.
1H-NMR (300 MHz, DMSO-d6) δ 0.58 (m, 2H) , 0.65 (m, 2H) , 0.83
(d, 3H, J = 7.5), 0.85 (d, 3H, J = 6.9), 1.12 (s, 9H) , 1.35 (m,
2H), 1.57 (m, 1H), 2.74 (m, 1H), 2.82 (m, 1H), 3.11 (m, 1H) ,
3.45 (m, 2H), 3.98 (m, 3H), 5.17 (m, 1H), 7.24 (m, 6H), 8.23
(d, 1H, J = 6.6), 8.71 (d, 1H, J = 4.8).
Example 28
((1S)-1-((((1S)-1-Benzyl-3-(cyclopropylamino)-2,3-
dioxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-isopropoxyethyloxyl ester (Compound 28)

Following the reaction in an analogous manner to Example
1 and using the compounds of Reference Examples 24 and 9 in place
of the compounds of Reference Examples 1 and 8 respectively,
the title compound was obtained as colorless crystals, via
((1S)-1-((((1S)-1-benzyl-3-(cyclopropylamino)-2-hydroxy-3-
oxopropyl)amino)carbonyl)-3-methylbutyl)carbamic acid
2-isopropoxyethyl ester.

1H-NMR (300 MHz, DMSO-d6) δ 0.58 (m, 2H) , 0.65 (m, 2H) , 0.83
(d, 3H, J = 7.2), 0.85 (d, 3H, J = 6.9), 1.07 (d, 6H, J = 5.7),
1.35 (m, 2H), 1.57 (m, 1H) , 2.74 (in, 1H) , 2.82 (m, 1H) , 3.12
(m, 1H) , 3.50 (m, 2H) , 3.55 (m, 1H) , 4.01 (m, 3H) , 5.17 (m, 1H) ,
7.24 (m, 6H), 8.22 (d, 1H, J = 6.9), 8.71 (d, 1H, J = 3.6).
Test Example 1
(1) Measurement of inhibitory activity against µ-calpain and
m-calpain
The inhibitory activity against [X-calpain and m-calpain
was assayed according to the method described in Anal. Biochem.
1993, vol. 208, p. 387-392. That is, to 2.5 µL of a DMSO solution
containing a varying concentration of the test sample in a
96-well plate was added 200 µL of a reaction solution containing
0.5 mg/mL casein, 50mM Tris-HCl buffer (pH 7.4), 20 mM
dithiothreitol and 1.0 nmol µ-calpain (derived from human red
blood cells; available from Cosmo Bio Co. Ltd.) or m-calpain
(derived from porcine kidney; available from Cosmo Bio Co. Ltd. ) .
After 20mM aqueous calcium chloride (50 µL) was added thereto,
the mixture was incubated at 30°C for 60 minutes. Then, 100
µL of the reaction solution was transferred to another 96-well
plate, and purified water (50 µL) and 50% aqueous solution (100
µL) of Protein Assay Dye Reagent (available from Bio-Rad
Laboratories, Inc.; catalogue No. 500-600) were added thereto.
The reaction mixture was allowed to stand at room temperature
for 15 minutes, and its absorbance was measured at 59 5 nm.
The absorbance of a reaction mixture prepared in the same
manner as mentioned above, except that a DMSO solution contained
no sample, was used as a control value, and that of a reaction

mixture prepared in the same manner as mentioned above, except
that 1 mM aqueous EDTA solution (50 µL) was used in place of
20 mM aqueous calcium chloride, was used as a blank value.
Inhibition rate was calculated by means of the following
equation, and the concentration required for 50% inhibition
(IC50) was determined.
Inhibition rate (%)={1-(measured value minus blank value)/
(control value minus blank value)} x 100
The calpain inhibitory activities are shown in Table 1,
which indicates that the compounds of the present invention
strongly inhibited activities of µ-calpain and m-calpain.

Test Example 2: Solubility
Solubility of the compounds of the present invention in
10 mM phosphate buffer (pH 7.0) was measured. The solubility
of the compounds of the present invention is shown in Table 2.
Table 2

Test Example 3: Permeability test with Caco-2 cells
1 x 105/cm2 of Caco-2 cells (Catalog No. HTB-37, available
from ATCC, passage number: 56) were seeded into a culture insert
(polycarbonate porous filter: FALCON(trade mark) 3096, pore
diameter 3 µm; area 0.31 cm2), and incubated for 22 days under
the conditions of 37°C and 5% CO2 to prepare a monolayer cell.
As a culture medium for the incubation, Dulbecco's modified
Eagle's minimum essential medium (GIBCO BRL) supplemented with
10% fetal calf serum (GIBCO BRL), antibiotic-antimycotic
mixture, liquid (GIBCO BRL) , non-essential amino acid solution.

(GIBCO BRL) and 2 mmol/L L-glutamine (GIBCO BRL) was used. The
cells were preincubated in advance in a Hanks' Balanced Salt
Solution (apical membrane side: pH 6.5, basolateralt membrane
side: pH 7.4) containing no sample or no control substance at
37°C for one hour. A Hanks' Balanced Salt Solution (pH 6.5,
37°C) containing a 10 pm sample or a control substance was run
to the apical membrane side (250 µL) , and the sample (950 µL)
permeated through the basolateral membrane was quantified.
That is , 500 µL was collected from the basolateral membrane side
after one or two hours, and the permeation coefficient was
measured. Propranolol was used as a positive control, and
14C-mannitol was used as a negative control. LC-MS/MS was used
for quantitative analysis of samples, and a liquid
scintillation counter was used for quantitative analysis of
14C-mannitol.
An amount of the sample or the control substance which
had been permeated through the basolateral membrane of Caco-2
monolayer cells was determined, and apparent permeation
coefficient (Papp) was calculated according to the formula:
PaPP= (δQ/δt) x (1/60AC0).
Papp : apparent permeation coefficient (cm/sec)
δQ/5t : permeation velocity (pmol/min)
A : area of monolayer cell = 0.33 cm2
C0 : initial concentration at apical membrane side
(pmol/mL)
Test Example 4 : Measurement of partition coefficient using I AM
column
Analysis by HPLC system was carried out under the

conditions given below, and retention time of each substance
was measured.
Column: IAM fast screening mini-column (Regis Technologies,
Inc.)
Mobile phase: Dulbecco's phosphate buffer (pH 7.4)
Detection wavelength: 250 nm
Column temperature: room temperature
Injection amount: 5.0 to 20 µL
Flow rate: 0.5 mL/min
Sample solution: 5 mg of sample was dissolved in 100 µL of
acetonitrile, and a mobile phase was added to make 1 mL
of a sample solution.
The measured value was inserted into the following
formula, and the partition coefficient (K'IAM) was calculated,
k' IAM = (tR-to)/t0
t0: retention time of the peak derived from acetonitrile
tR: retention time of the peak of the sample
The membrane permeability of the compounds of the present
invention was evaluated on the basis of the partition
coefficient (K'IAM) calculated from the permeability through
Caco-2 cell membrane (PapP (apical membrane side -> basolateral
membrane side)) and/or the correlated retention time in IAM
column analysis.
The results of Caco-2 cell permeability assay showed that
all compounds measured showed Papp = 10-6 or higher, a value
indicating that the permeability is not a rate-limiting step
in absorption. Also, an IAM column analysis revealed that the

compound tested showed k' IAM = 0.7 or higher, which was considered
to be equivalent to Caco-2 cell permeability of Papp=10-6.
According to these results, it was considered that oral
administration would not cause any problem on membrane
permeability in the digestive tract during absorption.

Test Example 5: Measurement of transportation rate into blood
The compound of the present invention was administered
orally to Macaca fascicularis (crab-eating monkey) at a dose
of 10 mg/kg. The blood was collected with the lapse of time,
and the concentration of each compound in the plasma was
measured. The maximum plasma concentration (Cmax) and the area
under the blood concentration-time curve (AUC) were shown in
Table 4.
When the compound of the present invention was
administered orally, it was transported into the blood with a
higher enzyme inhibitory activity (IC50) than that shown in Test

Example 1, elucidating that the compound of the present
invention has excellent pharmakokinetics.
Table 4

Experimental Example 6 Effect on rat retinal ischemia
reperfusion injury
Male SD rats (body weight: 150-200 g, purchased from
Charles River Japan, Inc.) were used. For anesthesia, a mixture
of equivalent amounts of 50 mg/mL ketamine injection and 20
mg/mL xylazine injection was administered intramuscularly at
1.0 mL/Kg body weight into the femora of the rats 15 minutes
before ischemia. To achieve ischemia, the optic nerve
including central retinal artery was ligated using a Sugita Clip
minitype (No. 98), and the blood flow was blocked for 55 minutes .
Such ligation was released 55 minutes after the above ligation,
and blood flow was made to run again into retina (hereinafter,
referred to as ischemia reperfusion). For normal group,
central retinal artery was only exposed and ischemia was not
set up. After 7 days from reperfusion in ischemia, a tissue
specimen was prepared. For preparation of the tissue specimen,
an excess amount of pentobarbital solution was

intraperitoneally administered to sacrifice the animal, and
eyeball was enucleated. The enucleated eyeball was dipped and
fixed for 24 hours in a fixing solution of 2% paraformaldehyde
and 2.5% glutaraldehyde (0.1 Mphosphate buffer, pH 7 . 4) . After
fixing, a paraffin embedded block of eyeball was prepared, and
such a paraffin embedded eyeball was sliced with a microtome
in a thickness of 3 µm at the section passing through the center
of the optic disc. The sections were stained with hematoxylin
and eosin (HE) in a conventional manner. The stained sections
were observed under an optical microscope, and ganglion cells
of retina per 0.25 mm width of retina section at 1-2 mm from
the center of the optic disc were counted.
Compound 17 was used as a drug to be tested. A solution
obtained by dissolving sodium carboxymethylcellulose in
distilled water to a concentration of 0.5% (CMC solution) was
orally administered to the control group, and a solution
obtained by suspending Compound 17 in a CMC solution at 1.0 %,
such that Compound 17 was administered at 100 mg/Kg body weight,
was orally administered to the drug group, both at 15 minutes
before start of ischemia and immediately after release from
ischemia (Compound 17 administration group). A CMC solution
was administered to control group and normal group in a similar
manner.
The results thereof are shown in Fig. 1. The ganglion
cell count decreased to about 1/4 of that of the normal group
(control group) due to ischemia reperfusion. In contrast.
Compound 17 administration (drug group) significantly
suppressed the decrease due to ischemia reperfusion in the
ganglion cell count. The above results suggest that Compound

17 of the present invention has an effect to improve retinal
ischemic disorder.

Compound 4, starch and lactose were blended well, and
formulated into granules for tableting according to the wet
granule tableting method. After addition of magnesium
stearate, the granules were compressed to make 400 tablets . The
tablets were, if required, coated with an enteric coating agent
(methacrylic acid copolymer).

The above components were mixed under sterile conditions
according to the conventional method to prepare eye drops.
Formulation Example 3: Injection

Compound 17 100 mg
Sodium chloride 900 mg
IN Sodium hydroxide q.s.
Distilled water for injection total volume 100 mL

The above components were mixed under sterile conditions
according to the conventional method to prepare an injection
preparation.
Industrial Applicability
Since the compounds of the formula (I) of the present invention
have excellent calpain inhibitory activity and good oral
absorbability, they are useful as a prophylactic and
therapeutic agent for various diseases related to calpain such
as ischemic disease, immunologic disease, multiple sclerosis
Alzheimer's disease, osteoporosis, diseases caused by brain
tissue damage, cataract, glaucoma, retinal disease,
retinochoroiditis (diabetic retinopathy, retinal vein
occulusion, macular degeneration, retinitis pigmentosa,
hypertensive retinopathy, retinal detachment, etc.),
posterior eyeball complications due to photocoagulation or a
disease involving neovascularization.

WE CLAIM:
1. A compound represented by the formula (I)

wherein R1 is
(1) a group represented by the formula (IIb) in which n is an integer of 2 to 5,

(2) a straight or branched C1-6 alkyl substituted by a pyridyl group optionally having a C1-3 alkyl
substituent on the pyridine ring, or
(3) a tetrahydrofuranyl group or a tetrahydropyranyl group;
R2 is a straight or branched C1-6 alkyl, optionally substituted by a phenyl; and
R3 is hydrogen, a straight or branched C1-6 alkyl or is selected from the group consisting
of cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.
2. The compound as claimed in Claim 1, wherein R1 is a group of the
formula (IIb)

in which n is an integer of 2 to 5.

3. The compound as claimed in Claim 1, wherein R3 is cyclopropyl.
4. The compound as claimed in claim 1 selected from the group consisting of
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 5-methoxy-3-oxapentyl ester,
((1S)-1-((((1S)-1-benzyl-2,3-dioxo-3-(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 8-methoxy-3,6-dioxaOctyl ester,
((1S)-1 -((((1S)-1 -benzyl-2,3-dioxo-3-(cyclopropylamino)propyl)amino)carbonyl)-3-
methylbutyl)carbamic acid 11-methoxy-3,6,9-trioxaundecanyl ester, or
((1 S)-1-((((1S)-1 -benzyl-3-(cyclopropyIamino)-2,3-dioxopropyl)amino)carbonyl)-3 -
methylbutyl)carbamic acid 2-(pyridin-2-yl)ethyl ester.
5. A medicament comprising the compound as claimed in Claim 1.

6. The compound as claimed in Claim 1, which is ((1S)-1-((((1S)-1-
benzyl-2,3-dioxo-3-(cyclopropylamino)propyl)amino)carbonyl)-3-methylbutyl)carbamic acid 5-
methoxy-3-oxapentyl ester.

(54) Title: ALPHA-KETOAMIDE DERIVATIVE, AND PRODUCTION METHOD AND USE THEREOF

(57) Abstract: The present invention provides a compound represented by the formula (I): (INSERT CHEMICAL FORMULA)
(wherein R1 is a lower alkyl substituted by a lower alkoxy or a heterocyclic group, or a heterocyclic group; R2 is a lower alkyl
optionally substituted by a phenyl; and R3 is a lower alkyl optionally substituted by a halogen, a lower alkoxy or a phenyl, or a
fused polycyclic hydrocarbon group), which is well absorbed orally, exhibits durability of good blood level and has potent calpain
inhibitory aclivity.

ALPHA-KETOAMIDE DERIVATIVE, AND PRODUCTION METHOD AND USE THEREOF

Documents:

Inventors:

PCT Conventions: