Title of Invention

A NOVEL PROCESS FOR SYNTHESIS OF ITOPRIDE

Abstract The present invention relates to a novel and improved process for the preparation of n-[4-[2-(dimethylamino)ethoxy]benzyl]-3,4-dimethoxybenzamide- known as Itopride, via a novel intermediate N-(4-hydroxybenzyl)-3,4-dimethoxybenzamide.
Full Text FORM 2
THE PATENTS ACT 1970
(Act 39 of 1970)
PROVISIONAL SPECIFICATION
(SECTION 10)
NOVEL VANILLOID RECEPTOR LIGANDS, PHARMACEUTICAL
COMPOSITIONS CONTAINING THEM, AND PROCESS FOR THEIR PREPARATION
Glenmark Pharmaceuticals S.A.
Registered address:
2nd Floor, Swisscom Building,
Rue de la Maladiere 23, 2000
Neuchatel, Switzerland
THE FOLLOWING SPECIFICATION DESCRIBES THE NATURE OF THE INVENTION

Field of the Invention
The present invention relates to novel vanilloid receptor ligands, in particular VR1 receptor antagonists, and uses thereof for treating diseases, conditions and/or disorders modulated by a vanilloid receptor.
Background of the Invention
Pain is the most common symptom for which patients seek medical advice and treatment. Pain can be acute or chronic. While acute pain is usually self-limiting, chronic pain persists for 3 months or longer and can lead to significant changes in a patient's personality, lifestyle, functional ability and overall quality of life (see K. M. Foley, Pain, in Cecil Textbook of Medicine 100-107 (see J. C. Bennett and F. Plum eds., 20th ed. 1996)). The sensation of pain can be triggered by any number of physical or chemical stimuli and the sensory neurons which mediate the response to this harmful stimuli are termed as "nociceptors". Nociceptors are primary sensory afferent (C and A5 fibers) neurons that are activated by a wide variety of noxious stimuli including chemical, mechanical, thermal, and proton (pH Moreover, chronic pain can be classified as either nociceptive or neuropathic. Nociceptive pain includes tissue injury-induced pain and inflammatory pain such as that associated with arthritis. Neuropathic pain is caused by damage to the sensory nerves of the peripheral or central nervous system and is maintained by aberrant somatosensory processing. There is a large body of evidence relating activity at vanilloid receptors (VR1) (see V. Di Marzo et al., Current Opinion in Neurobiology 12:372-379 (2002)) to pain processing.
The lipophilic vanilloid, Capsaicin(8-methyl-N-vanillyl-6-nonenamides; CAP) is known to stimulate pain pathways through the release of a variety of sensory afferent neurotransmitters via a specific cell surface capsaicin receptor, cloned as the first vanilloid receptor (VR1 now known as TRPV1) (see Caterina MJ,et.al„ Science , 2000 Apr 14; 288(5464):306-13). Capsaicin is the main pungent component in hot pepper. Hot pepper has been used, for a long time, not only as a spice but also as a traditional medicine in the treatment of gastric disorders and when applied locally, for the relief of pain and inflammation. CAP has a wide spectrum of biological actions, and not only
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exhibits effects on the cardiovascular and respiratory systems but also induces pain and irritancy on local application. CAP, however, after such induction of pain, induces desensitization, both to CAP itself and also to other noxious stimuli to stop the pain. The intradermal administration of capsaicin is characterized by an initial burning or hot sensation followed by a prolonged period of analgesia. The analgesic component of VRl receptor activation is thought to be mediated by a capsaicin-induced desensitization of the primary sensory afferent terminal. Based on this property, CAP and its analogues such as olvanil, nuvanil, DA-5018, SDZ-249482, resiniferatoxin are either used or are under development as analgesic agents, therapeutic agents for urinary incontinence or skin disorder {see Wriggleworth and Walpore, Drugs of the Future, 23, pp531-538, (1998)).
VRl is widely expressed in non-neuronal tissues in various organ systems, and the functional roles of VRl in various systems are not properly understood at this time. Increasing number of animal studies have revealed the possible involvement of VRl receptors in various pathologies and based on such information VRl is now being considered as a molecular target for various indications such as migraine, arthralgia, diabetic neuropathy, neurodegeneration, neurotic skin disorder, stroke, cardiac pain arising from an ischemic myocardium, Huntington's disease, memory deficits, restricted brain function, amyotrophic lateral sclerosis (ALS), dementia, urinary bladder hypersensitiveness, urinary incontinence, vulvodynia, pruritic conditions such as uremic pruritus, irritable bowel syndrome including gastro-esophageal reflux disease, enteritis ,ileitis , stomach-duodenal ulcer, inflammatory bowel disease including Crohn's disease, celiac disease and inflammatory diseases such as pancreatitis, and in respiratory disorders such as allergic and non-allergic rhinitis, asthma or chronic obstructive pulmonary disease, irritation of skin, eye or mucous membrane, dermatitis, and in non specific disorders such as fervescence, retinopathy, muscle spasms, emesis, dyskinesias or depression. Specifically VRl antagonists are likely to be used in multiple sub-types of pain such as acute, chronic, neuropathic pain or post-operative pain, as well as in pain due to neuralgia (e.g. post herpetic neuralgia, trigeminal neuralgia; and in pain due to diabetic neuropathy or dental pain as well as in cancer pain. Additionally, VRl antagonists will also prove useful in the treatment of inflammatory pain conditions e.g. arthritis, and osteoarthritis. VRl antagonists hold potential benefit in diabetes, obesity,
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urticaria, actinic keratosis, keratocanthoma, alopecia, Meniere's disease, tinnitus, hyperacusis and anxiety disorders.
Certain class of natural and synthetic compounds which modulate the function of Vanilloid Receptor (VR1) have been characterised by the presence of a vanillyl (4-hydroxy 3-methoxybenzyl) group or a functionally equivalent group and the same have been widely studied and is extensively reviewed by Szallasi and Blumberg (see The Ame. Soc. for Pharmacology and Experimental Therapeutics, 1999, Vol. 51, No. 2.).

Various vanilloid agonists and antagonists have been developed for the treatment of pain; the agonists work through desensitizing the receptor while antagonists block its stimulation by (patho) physiological ligands. The first antagonist to be developed was Capsazepine belonging to Novartis which has the formula A
HO.
Capsazepine, A
And at present various other VR1 antagonists being developed are





HO
tSOiCH
HO.

^PAC-20030, B

\ *? H



A-425619, D

AMC-9810, E

AmorePacific's PAC-20030 which has the formula B, Neurogen's BCTC which has the formula C ,Abbott's A-425619 which has the formula D and Amgen's AMG-9810 which has the formula E ,all of which are at the preclinical stage
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EP Patent Application Publication No 462761 discloses (benzopyranyl) phenylureas and related compounds as potassium channel activators and a method of using theses and other compounds having potassium channel activating activity as antiischemic and/or anti-arrhythmic agents and pharmaceutical compositions thereof .In particular the patent discloses a compound of general formula I.



wherein A, X, Y, R1, R2, R3, R4, R5, R6 and R7 have various meaning.
International Application, publication number WO 2003/080578 discloses heteroaromatic ureas as Vanilloid receptor (VR1) modulators, in particular antagonists, for treating pain and/or inflammation. In particular the patent discloses a compound of general formula (I).


-(CR5R6)n-Y

(I)
wherein A, B, D, E, X, Y, R1, R2, R3, R4, R5 and R6 have various meaning
International Application, publication number WO05/007652 describes substituted quinolin-4yl-amine analogues useful in the treatment of conditions related to capsaicin receptor activation. Another International Application, publication number WO05/009977 discloses substituted pyrmidinyl-4-yl-amine analogues used to modulate Vanilloid receptor activity.
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Other Vanilloid receptor modulating compounds are disclosed in US pat Nos. 6933311, 6939891 and PCT International Publication Nos WO02/08221, WO02/16317, WO02/16318, WO02/16319, WO04/103281, WO04/108133 and WO04/111009.
In efforts to discover better analgesics for the treatment of both acute and chronic pain, and to develop treatments for various neuropathic pain states, there still exists a need for a more effective and safe therapeutic treatment of diseases, conditions and/or disorders modulated by vanilloid receptor.
Summary of Invention
The present invention relates to VR1 receptor ligands of general formula (I):

wherein:
XisO,-S(0)m,orNRe;
R1 and R2 are joined together to form an optionally substituted 3 to 7 membered saturated
or unsaturated cyclic ring, which may optionally include a heteroatom selected from 0,
NR or S(0)m ; with the proviso that R and R are joined together does not represent
cyclopentyl or cyclohexyl ring
R3 and R4 are independently hydrogen, cyano, halogen, -OR8, substituted or unsubstituted
alkyl or -NR9R10
R5 R6 and R7 are independently hydrogen, nitro, cyano, halogen, -OR8, substituted or
unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted
alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted
cycloalkylalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted
aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted heteroaryl,
substituted or unsubstituted heteroarylalkyl, substituted or unsubstituted heterocyclic
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group, substituted or unsubstituted heterocyclylalkyl, -NR9R10, -C(=L)-R9, -C(0)0-R9, -C(0)NR9R10, -S(0)m-R9, -S(0)m-NR9R10;
o
R is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkylalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heteroarylalkyl, substituted or unsubstituted heterocyclic group, substituted or unsubstituted heterocyclylalkyl, -NR9R10, -C(=L)-R9, -C(0)0-R9, -C(0)NR9R10, -S(0)m-R9, -S(0)m-NR9R10;
R9 and R10 may be joined together to form an optionally substituted 3 to 7 membered saturated or unsaturated cyclic ring, which may optionally include at least two heteroatoms selected from 0, NRe or S; each occurrence of R9 and R10 may be same or different and are independently hydrogen, -0Ra, -SRa, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkylalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heteroarylalkyl, substituted or unsubstituted heterocyclic group, substituted or unsubstituted heterocyclylalkyl,-NRaRb, -C(=L)-Ra, -C(0)0- Ra, -C(0)NRaRb, -S(0)m-Ra or -S(0)m-NRaRb;
each occurrence of Ra and Rb is independently hydrogen, -0RC, -SRC, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkylalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted cycloalkenylalkyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heteroarylalkyl, substituted or unsubstituted heterocyclic group, substituted or unsubstituted heterocyclylalkyl, -C(=L)-RC, -C(0)0-Rc, -C(0)NRcRd, -S(0)m-Rc, -S(0)m-NRcRd, -NRcRd, or a protecting group, or Ra and Rb taken together with the nitrogen atom to which they are attached may be joined to form an optionally substituted 3 to 7 membered
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saturated or unsaturated cyclic ring, which may optionally include at least two heteroatoms selected from O, NReor S;
each occurrence of m is independently 0, 1 or 2;
each occurrence of L is independently 0, S, or NRe;
n is an integer 0 to 4
p is an integer 0 to 3
q is an integer 0 to 3
each occurrence of Rc and Rd is independently hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkylalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heterocyclic group, substituted or unsubstituted heterocyclylalkyl, or a substituted or unsubstituted heteroarylalkyl or a protecting group, or Rc and Rd taken together with the nitrogen atom to which they are attached may be joined to form an optionally substituted 3 to 7 membered saturated or unsaturated cyclic ring, which may optionally include at least two heteroatoms selected from O, NReor S;
each occurrence of Re is independently hydrogen or substituted or unsubstituted alkyl;
or a prodrug thereof, pharmaceutically acceptable salt thereof, or hydrate or solvate thereof Preferred is a compound of formula (I) where X is 0
Further preferred is a compound of formula (I) where R and R are joined together to form an optionally substituted 3 to 7 member saturated cyclic ring, which may optionally include a heteroatom selected from 0, NR8;
Further preferred is a compound of formula (I) where R1 and R2 are joined together to form an optionally substituted 3 to 7 member saturated cyclic ring, which may optionally include a heteroatom selected from 0, NR8 is selected from
\ M
CH3
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Further preferred is a compound of formula (I) where R1 and R2 are joined together to form a 6 member saturated cyclic ring, which include a heteroatom selected from 0, NR8 , where R8 is methyl;
Further preferred is a compound of formula (I) where R1 and R2 are joined together to form a N-methyl piperidine ring
Further preferred is a compound of formula (I) where R1 and R2 are joined together to form a pyrane ring
Further preferred is a compound of formula (I) where R1 and R2 are joined together to form a cyclobuatane ring
Further preferred is a compound of formula (I) where R3 and R4 is Hydrogen
Further preferred is a compound of formula (I) where n is zero
Further preferred is a compound of formula (I) where p is zero
Further preferred is a compound of formula (I) where q is zero
Representative compounds of the present invention include those specified below
and pharmaceutical^ acceptable salts thereof. The present invention should not be
construed to be limited to them.
1. (±)l-{3,4-Dihydro-r-(methyl)spiro-[2//-l-benzopyran-2,4'-piperidine]-
4-yl} -3-(isoquinoline-5-y l)urea
2. (±)l-(2',3, 3',4, 5',6'-Hexahydrospiro-[2#-l-benzopyran-2,4'-pyran]-4-yl)-3-(isoquinoline-5-yl)urea
3. (±)l-(3,4-Dihydrospiro[2//-l-benzopyran-2,l'-cyclobutan]-4-yl)-3-(isoquinolin-5-yl) urea
The present invention also provides a pharmaceutical composition comprising at least one compound of the present invention and a pharmaceutically acceptable excipient (such as a pharmaceutically acceptable carrier or diluent). Preferably, the pharmaceutical composition comprises a therapeutically effective amount of at least one compound of the present invention. The compound of the present invention may be associated with a pharmaceutically acceptable excipient (such as a carrier or a diluent) or be diluted by a
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carrier, or enclosed within a carrier which can be in the form of a capsule, sachet, paper or other container.
The compounds and pharmaceutical compositions of the present invention are useful in the treatment of diseases, conditions and/or disorders modulated by vanilloid antagonists.
The present invention further provides a method of treating a disease, condition and/or disorder modulated by vanilloid VR1 receptor antagonists in a subject in need thereof by administering to the subject a therapeutically effective amount of a compound or a pharmaceutical composition of the present invention.
Detailed Description of the Invention
Definitions
The term "alkyl" refers to a straight or branched hydrocarbon chain radical consisting solely of carbon and hydrogen atoms, containing no unsaturation, having from one to eight carbon atoms, and which is attached to the rest of the molecule by a single bond, e.g., methyl, ethyl, n-propyl, 1-methylethyl (isopropyl), n-butyl, n-pentyl, and 1,1-dimethylethyl (t-butyl). The term "Ci-6 alkyl" refers to an alkyl chain having 1 to 6 carbon atoms.
The term "alkenyl" refers to an aliphatic hydrocarbon group containing a carbon-carbon double bond and which may be a straight or branched chain having 2 to about 10 carbon atoms, e.g., ethenyl, 1-propenyl, 2-propenyl (allyl), iso-propenyl, 2-methyl-l-propenyl, 1-butenyl, and 2-butenyl.
The term "alkynyl" refers to a straight or branched chain hydrocarbyl radical having at least one carbon-carbon triple bond, and having 2 to about 12 carbon atoms (with radicals having 2 to about 10 carbon atoms being preferred), e.g., ethynyl, propynyl, and butynyl.
The term "alkoxy" denotes an alkyl group attached via an oxygen linkage to the rest of the molecule. Representative examples of such groups are -OCH3 and -OC2H5.
The term "cycloalkyl" denotes a non-aromatic mono or multicyclic ring system of 3 to about 12 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. Examples of multicyclic cycloalkyl groups include, but are not limited to,
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perhydronapththyl, adamantyl and norbornyl groups, bridged cyclic groups or sprirobicyclic groups, e.g., sprio (4,4) non-2-yl.
The term "cycloalkylalkyl" refers to a cyclic ring-containing radical having 3 to about 8 carbon atoms directly attached to an alkyl group. The cycloalkylalkyl group may be attached to the main structure at any carbon atom in the alkyl group that results in the creation of a stable structure. Non-limiting examples of such groups include cyclopropylmethyl, cyclobutylethyl, and cyclopentylethyl.
The term "cycloalkenyl" refers to a cyclic ring-containing radical having 3 to about 8 carbon atoms with at least one carbon-carbon double bond, such as cyclopropenyl, cyclobutenyl, and cyclopentenyl.
The term "aryl" refers to an aromatic radical having 6 to 14 carbon atoms such as phenyl, naphthyl, tetrahydronapthyl, indanyl, and biphenyl.
The term "arylalkyl" refers to an aryl group as defined above directly bonded to an alkyl group as defined above, e.g., -CH2C6H5 and -C2H5C6H5.
The term "heterocyclic ring" refers to a stable 3- to 15-membered ring radical which consists of carbon atoms and from one to five heteroatoms selected from nitrogen, phosphorus, oxygen and sulfur. For purposes of this invention, the heterocyclic ring radical may be a monocyclic, bicyclic or tricyclic ring system, which may include fused, bridged or spiro ring systems, and the nitrogen, phosphorus, carbon, oxygen or sulfur atoms in the heterocyclic ring radical may be optionally oxidized to various oxidation states. In addition, the nitrogen atom may be optionally quaternized; and the ring radical may be partially or fully saturated (i.e., heterocyclic or heteroaryl). Examples of such heterocyclic ring radicals include, but are not limited to, azetidinyl, acridinyl, benzodioxolyl, benzodioxanyl, benzofurnyl, carbazolyl, cinnolinyl, dioxolanyl, indolizinyl, naphthyridinyl, perhydroazepinyl, phenazinyl, phenothiazinyl, phenoxazinyl, phthalazinyl, pyridyl, pteridinyl, purinyl, quinazolinyl, quinoxalinyl, quinolinyl, isoquinolinyl, tetrazoyl, imidazolyl, tetrahydroisouinolyl, piperidinyl, piperazinyl, 2-oxopiperazinyl, 2-oxopiperidinyl, 2-oxopyrrolidinyl, 2-oxoazepinyl, azepinyl, pyrrolyl, 4-piperidonyl, pyrrolidinyl, pyrazinyl, pyrimidinyl, pyridazinyl, oxazolyl, oxazolinyl, oxasolidinyl, triazolyl, indanyl, isoxazolyl, isoxasolidinyl, morpholinyl, thiazolyl, thiazolinyl, thiazolidinyl, isothiazolyl, quinuclidinyl, isothiazolidinyl, indolyl, isoindolyl, indolinyl, isoindolinyl, octahydroindolyl, octahydroisoindolyl, quinolyl, isoquinolyl,
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decahydroisoquinolyl, benzimidazolyl, thiadiazolyl, benzopyranyl, benzothiazolyl, benzooxazolyl, furyl, tetrahydrofurtyl, tetrahydropyranyl, thienyl, benzothienyl, thiamorpholinyl, thiamorpholinyl sulfoxide, thiamorpholinyl sulfone, dioxaphospholanyl, oxadiazolyl, chromanyl, and isochromanyl. The heterocyclic ring radical may be attached to the main structure at any heteroatom or carbon atom that results in the creation of a stable structure.
The term "heterocyclyl" refers to a heterocyclic ring radical as defined above. The heterocyclyl ring radical may be attached to the main structure at any heteroatom or carbon atom that results in the creation of a stable structure.
The term "heterocyclylalkyl" refers to a heterocyclic ring radical directly bonded to an alkyl group. The heterocyclylalkyl radical may be attached to the main structure at any carbon atom in the alkyl group that results in the creation of a stable structure.
The term "heteroaryl" refers to an aromatic heterocyclic ring radical. The heteroaryl ring radical may be attached to the main structure at any heteroatom or carbon atom that results in the creation of a stable structure.
The term "heteroarylalkyl" refers to a heteroaryl ring radical directly bonded to an alkyl group. The heteroarylalkyl radical may be attached to the main structure at any carbon atom in the alkyl group that results in the creation of a stable structure.
Unless otherwise specified, the term "substituted" as used herein refers to substitution with any one or any combination of the following substituents: hydroxy, halogen, carboxyl, cyano, nitro, oxo (=0), thio (=S), substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenylalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted amino, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heterocyclylalkyl ring, substituted or unsubstituted heteroarylalkyl, substituted or unsubstituted heterocyclic ring, substituted or unsubstiuted guanidine, -COORx, -C(0)Rx, -C(S)Rx, -C(0)NRxRy, -C(0)ONRxRy, -NRxCONRyRz, -N(Rx)SORy, -N(Rx)S02Ry, -(=N-N(Rx)Ry), -NRxC(0)ORy, -NRxRy, -NRxC(0)Ry, -NRxC(S)Ry, -NRxC(S)NRyRz, -SONRxRy, -S02NRxRy, -ORx, -ORxC(0)NRyRz, -ORxC(0)ORy, -OC(0)Rx, -OC(0)NRxRy, -RxNRyC(0)Rz, -RxORy, -RxC(0)ORy, -
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RxC(0)NRyRz, -RxC(0)Ry, -RxOC(0)Ry, -SRx, -SORx, -S02Rx, and -0N02) wherein RX, Ry and Rz are independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted amino, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted heterocyclylalkyl ring, substituted or unsubstituted heteroarylalkyl, or substituted or unsubstituted heterocyclic ring. According to one embodiment, the substituents in the aforementioned "substituted" groups cannot be further substituted. For example, when the substituent on "substituted alkyl" is "substituted aryl", the substituent on "substituted aryl" cannot be "substituted alkenyl".
The term "protecting group" or "PG" refers to a substituent that is employed to block or protect a particular functionality while other functional groups on the compound may remain reactive. For example, an "amino-protecting group" is a substituent attached to an amino group that blocks or protects the amino functionality in the compound. Suitable amino-protecting groups include, but are not limited to, acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and 9-fluorenylmethylenoxycarbonyl (Fmoc). Similarly, a "hydroxy-protecting group" refers to a substituent of a hydroxy group that blocks or protects the hydroxy functionality. Suitable hydroxy-protecting groups include, but are not limited to, acetyl, benzyl, tetrahydropyranyl and silyl. A "carboxy-protecting group" refers to a substituent of the carboxy group that blocks or protects the carboxy functionality. Suitable carboxy-protecting groups include, but are not limited to, -CH2CH2S02Ph, cyanoethyl, 2-(trimethylsilyl)ethyl, 2-(trimethylsilyl)ethoxymethyl, 2-(p-toluenesulfonyl)ethyl, 2-(p-nitrophenylsulfenyl)ethyl, 2-(diphenylphosphino)-ethyl, and nitroethyl. For a general description of protecting groups and their use, see, T. W. Greene, Protective Groups in Organic Synthesis, John Wiley & Sons, New York, 1991.
The term "prodrug" means a compound that is transformed in vivo to yield a compound of Formula (I) or a pharmaceutical^ acceptable salt, hydrate or solvate of the compound. The transformation may occur by various mechanisms, such as through hydrolysis in blood. A discussion of the use of prodrugs is provided by T. Higuchi and
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W. Stella, "Pro-drugs as Novel Delivery Systems," Vol. 14 of the A.C.S. Symposium Series, and in Bioreversible Carriers in Drug Design, ed. Edward B. Roche, American Pharmaceutical Association and Pergamon Press, 1987.
The term "treating" or "treatment" of a state, disorder or condition includes:
(1) preventing or delaying the appearance of clinical symptoms of the state, disorder or condition developing in a subject that may be afflicted with or predisposed to the state, disorder or condition but does not yet experience or display clinical or subclinical symptoms of the state, disorder or condition;
(2) inhibiting the state, disorder or condition, i.e., arresting or reducing the development of the disease or at least one clinical or subclinical symptom thereof; or
(3) relieving the disease, i.e., causing regression of the state, disorder or condition or at least one of its clinical or subclinical symptoms.
The benefit to a subject to be treated is either statistically significant or at least perceptible to the subject or to the physician.
The term "subject" includes mammals (especially humans) and other animals, such as domestic animals (e.g., household pets including cats and dogs) and non-domestic animals (such as wildlife).
A "therapeutically effective amount" means the amount of a compound that, when administered to a subject for treating a state, disorder or condition, is sufficient to effect such treatment. The "therapeutically effective amount" will vary depending on the compound, the disease and its severity and the age, weight, physical condition and responsiveness of the subject to be treated.
Pharmaceutically acceptable salts forming part of this invention include salts derived from inorganic bases (such as Li, Na, K, Ca, Mg, Fe, Cu, Zn, and Mn), salts of organic bases (such as N,N'-diacetylethylenediamine, glucamine, triethylamine, choline, hydroxide, dicyclohexylamine, metformin, benzylamine, trialkylamine, and thiamine), salts of chiral bases (such as alkylphenylamine, glycinol, and phenyl glycinol), salts of natural amino acids (such as glycine, alanine, valine, leucine, isoleucine, norleucine, tyrosine, cystine, cysteine, methionine, proline, hydroxy proline, histidine, ornithine, lysine, arginine, and serine), salts of non-natural amino acids (such as D-isomers or substituted amino acids), salts of guanidine, salts of substituted guanidine (wherein the substituents are selected from nitro, amino, alkyl, alkenyl, or alkynyl), ammonium salts,
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substituted ammonium salts, and aluminum salts. Other pharmaceutically acceptable salts include acid addition salts (where appropriate) such as sulphates, nitrates, phosphates, perchlorates, borates, hydrohalides, acetates (such as trifluroacetate), tartrates, maleates, citrates, fumarates, succinates, palmoates, methanesulphonates, benzoates, salicylates, benzenesulfonates, ascorbates, glycerophosphates, and ketoglutarates. Yet other pharmaceutically acceptable salts include, but are not limited to, quaternary ammonium salts of the compounds of invention with alkyl halides or alkyl sulphates (such as Mel or (Me)2 SO4).
Pharmaceutically acceptable solvates includes hydrates and other solvents of crystallization (such as alcohols). The compounds of the present invention may form solvates with low molecular weight solvents by methods known in the art.
Certain compounds of present invention are capable of existing in stereoisomeric forms (e.g. diastereomers and enantiomers) and the invention extends to each of these stereoisomeric forms and to mixtures thereof including racemates. The different stereoisomeric forms may be separated one from the other by the usual methods, or any given isomer may be obtained by stereospecific or asymmetric synthesis. The invention also extends to any tautomeric forms and mixtures thereof.
Pharmaceutical Compositions
The pharmaceutical composition of the present invention comprises at least one compound of the present invention and a pharmaceutically acceptable excipient (such as a pharmaceutically acceptable carrier or diluent). Preferably, the pharmaceutical composition comprises a therapeutically effective amount of the compound(s) of the present invention. The compound of the present invention may be associated with a pharmaceutically acceptable excipient (such as a carrier or a diluent) or be diluted by a carrier, or enclosed within a carrier which can be in the form of a capsule, sachet, paper or other container.
Examples of suitable carriers include, but are not limited to, water, salt solutions, alcohols, polyethylene glycols, polyhydroxyethoxylated castor oil, peanut oil, olive oil, gelatin, lactose, terra alba, sucrose, dextrin, magnesium carbonate, sugar, cyclodextrin, amylose, magnesium stearate, talc, gelatin, agar, pectin, acacia, stearic acid or lower alkyl ethers of cellulose, silicic acid, fatty acids, fatty acid amines, fatty acid monoglycerides
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and diglycerides, pentaerythritol fatty acid esters, polyoxyethylene, hydroxymethylcellulose and polyvinylpyrrolidone.
The carrier or diluent may include a sustained release material, such as glyceryl monostearate or glyceryl distearate, alone or mixed with a wax.
The pharmaceutical composition may also include one or more pharmaceutical^ acceptable auxiliary agents, wetting agents, emulsifying agents, suspending agents, preserving agents, salts for influencing oxmetic pressure, buffers, sweetening agents, flavoring agents, colorants, or any combination of the foregoing. The pharmaceutical composition of the invention may be formulated so as to provide quick, sustained, or delayed release of the active ingredient after administration to the subject by employing procedures known in the art.
The pharmaceutical compositions of the present invention may be prepared by conventional techniques, e.g., as described in Remington: The Science and Practice of Pharmacy, 20th Ed., 2003 (Lippincott Williams & Wilkins). For example, the active compound can be mixed with a carrier, or diluted by a carrier, or enclosed within a carrier, which may be in the form of an ampoule, capsule, sachet, paper, or other container. When the carrier serves as a diluent, it may be a solid, semi-solid, or liquid material that acts as a vehicle, excipient, or medium for the active compound. The active compound can be adsorbed on a granular solid container, for example, in a sachet.
The pharmaceutical compositions may be in conventional forms, for example, capsules, tablets, aerosols, solutions, suspensions or products for topical application.
The route of administration may be any route which effectively transports the active compound of the invention to the appropriate or desired site of action. Suitable routes of administration include, but are not limited to, oral, nasal, pulmonary, buccal, subdermal, intradermal, transdermal, parenteral, rectal, depot, subcutaneous, intravenous, intraurethral, intramuscular, intranasal, ophthalmic (such as with an ophthalmic solution) or topical (such as with a topical ointment). The oral route is preferred.
Solid oral formulations include, but are not limited to, tablets, capsules (soft or hard gelatin), dragees (containing the active ingredient in powder or pellet form), troches and lozenges. Tablets, dragees, or capsules having talc and/or a carbohydrate carrier or binder or the like are particularly suitable for oral application. Preferable carriers for
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tablets, dragees, or capsules include lactose, cornstarch, and/or potato starch. A syrup or elixir can be used in cases where a sweetened vehicle can be employed.
A typical tablet that may be prepared by conventional tabletting techniques may contain: (1) Core: Active compound (as free compound or salt thereof), 250 mg colloidal silicon dioxide (Aerosil®), 1.5 mg microcrystalline cellulose (Avicel®), 70 mg modified cellulose gum (Ac-Di-Sol®), and 7.5 mg magnesium stearate; (2) Coating: HPMC, approx. 9 mg Mywacett 9-40 T and approx. 0.9 mg acylated monoglyceride
Liquid formulations include, but are not limited to, syrups, emulsions, soft gelatin and sterile injectable liquids, such as aqueous or non-aqueous liquid suspensions or solutions.
For parenteral application, particularly suitable are injectable solutions or suspensions, preferably aqueous solutions with the active compound dissolved in polyhydroxylated castor oil.
Methods of Treatment
The present invention provides compounds and pharmaceutical formulations thereof that are useful in the treatment of diseases, conditions and/or disorders modulated by vanilloid VR1 receptor antagonists .
The present invention further provides a method of treating a disease, condition and/or disorder modulated by vanilloid receptor antagonists in a subject in need thereof by administering to the subject a therapeutically effective amount of a compound or a pharmaceutical composition of the present invention. The method is particularly useful for treating diseases, conditions and/or disorders modulated by VR1 receptor antagonists. Diseases, conditions, and/or disorders that are modulated by vanilloid receptor antagonists include, but are not limited to, migraine, arthralgia, diabetic neuropathy, neurodegeneration, neurotic skin disorder, stroke, cardiac pain arising from an ischemic myocardium, Huntington's disease, memory deficits, restricted brain function, amyotrophic lateral sclerosis (ALS), dementia, urinary bladder hypersensitiveness, urinary incontinence, vulvodynia, pruritic conditions such as uremic pruritus, irritable bowel syndrome including gastro-esophageal reflux disease, enteritis ,ileitis , stomach-duodenal ulcer, inflammatory bowel disease including Crohn's disease, celiac disease and inflammatory diseases such as pancreatitis, and in respiratory disorders such as allergic
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and non-allergic rhinitis, asthma or chronic obstructive pulmonary disease, irritation of skin, eye or mucous membrane, dermatitis, and in non specific disorders such as fervescence, retinopathy, muscle spasms, emesis, dyskinesias or depression. Specifically in multiple sub-types of pain such as acute, chronic, neuropathic pain or post-operative pain, as well as in pain due to neuralgia (e.g. post herpetic neuralgia, trigeminal neuralgia; and in pain due to diabetic neuropathy or dental pain as well as in cancer pain. Additionally, VR1 antagonists hold potential benefit in the treatment of inflammatory pain conditions e.g. arthritis, and osteoarthritis, diabetes, obesity, urticaria, actinic keratosis, keratocanthoma, alopecia, Meniere's disease, tinnitus, hyperacusis and anxiety disorders.
As indicated above, the compounds of the present invention and their pharmaceutically acceptable salts or pharmaceutically acceptable solvates have Vanilloid receptor antagonist (VR1) activity and are believed to be of potential use for the treatment or prophylaxis of certain diseases or disorders mediated or associated with the activity of vanilloid receptor, including disorders such as pain, chronic pain, neuropathic pain, postoperative pain, rheumatoid arthritic pain, osteoarthritic pain, back pain, visceral pain, cancer pain, algesia, neuralgia, migraine, neuropathies, diabetic neuropathy, sciatica, HIV-related neuropathy, post-herpetic neuralgia, fibromyalgia, nerve injury, ischaemia, neurodegeneration, stroke, post stroke pain, multiple sclerosis, respiratory diseases, asthma, cough, COPD, inflammatory disorders, oesophagitis, gastroeosophagal reflux disorder (GERD), irritable bowel syndrome, inflammatory bowel disease, pelvic hypersensitivity, urinary incontinence, cystitis, burns, psoriasis, emesis, stomach duodenal ulcer and pruritus.
Thus the invention also provides a compounds or a pharmaceutically acceptable salt thereof, for use as an active therapeutic substance, in particular in the treatment or prophylaxis of diseases or disorders mediated or associated with the activity of vanilloid receptor. In particular the invention provides a compound of formula (I') or a pharmaceutically acceptable salt thereof for use in the treatment or prophylaxis of pain.
The invention further provides a method of treatment or prophylaxis of diseases or disorders mediated or associated with the activity of vanilloid receptor, in mammals
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including humans, which comprises administering to the sufferer a therapeutically effective amount of a compound of the present invention.
The invention provides for the use of a compound of the present invention or a pharmaceutically acceptable salt thereof or a pharmaceutically acceptable solvate thereof in the manufacture of a medicament for the treatment or prophylaxis of diseases or disorders mediated or associated with the activity of vanilloid receptor. The compound of the present invention has potent analgesic and antiinflammatory activity, and the pharmaceutical composition of the present invention thus may be employed to alleviate or relieve acute, chronic or inflammatory pains, suppress inflammation, or treat urgent urinary incontinence.
In accordance with another aspect of the present invention, there is also provided a method for alleviating and/or treating migraine, arthralgia, diabetic neuropathy, neurodegeneration, neurotic skin disorder, stroke, cardiac pain arising from an ischemic myocardium, Huntington's disease, memory deficits, restricted brain function, amyotrophic lateral sclerosis (ALS), dementia, urinary bladder hypersensitiveness, urinary incontinence, vulvodynia, pruritic conditions such as uremic pruritus, irritable bowel syndrome including gastro-esophageal reflux disease, enteritis , ileitis , stomach-duodenal ulcer, inflammatory bowel disease including Crohn's disease, celiac disease and inflammatory diseases such as pancreatitis, and in respiratory disorders such as allergic and non-allergic rhinitis, asthma or chronic obstructive pulmonary disease, irritation of skin, eye or mucous membrane, dermatitis, and in non specific disorders such as fervescence, retinopathy, muscle spasms, emesis, dyskinesias or depression. Specifically in multiple sub-types of pain such as acute, chronic, neuropathic pain or post-operative pain, as well as in pain due to neuralgia (e.g. post herpetic neuralgia, trigeminal neuralgia; and in pain due to diabetic neuropathy or dental pain as well as in cancer pain. Additionally in the treatment of inflammatory pain conditions e.g. arthritis, and osteoarthritis, diabetes, obesity, urticaria, actinic keratosis, keratocanthoma, alopecia, Meniere's disease, tinnitus, hyperacusis and anxiety disorders.
The compounds of the present invention in pharmaceutical dosage forms may be used in the form of their pharmaceutically acceptable salts, and also may be used alone or in appropriate association, as well as in combination with other pharmaceutically active compounds.
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The compounds of the present invention (including the pharmaceutical compositions and processes used therein) may be used alone or in combination with other pharmaceutical agents in the manufacture of a medicament for the therapeutic applications described herein.
General method of preparation
The compounds according to the present invention may be prepared by the following processes. The symbols X, R1, R2, R3, R4 R5, R6 and R7 when used in the formulae below are to be understood to represent those groups described above in relation to formula (I) unless otherwise indicated.



(I)
In one embodiment the compounds of general formula (I) wherein X, R , R , R , R4 R5' R6 and R7 ,n, p and q are as defined above can be synthesized by using the general process described in synthetic scheme I.
Scheme 1


(R')n °
x^A„Rvt R,AR!
^SH

"(*:) P. R3

X V

HO.



10

11

12

13


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In the above scheme I, the compound of formula (10) can be condensed with compounds of formula (11) in the presence of base (such as pyrrolidine, morpholine) to obtain the compound of general formula (12). The compound of general formula (12) can then be converted to the compound of general formula (13) using hydroxyl amine, which can further be reduced to a compound of general formula (14) in the presence of suitable reducing agents (such as Ni-Al alloy, or metal catalysed hydrogenation or lithium aluminum hydride). The compound of general formula (14) can then be treated with a compound of general formula (15) in the presence of base (such as triethylamine or pyridine) to yield the desired compound of general formula (I).
In another embodiment the compounds of general formula (I) wherein X, R1, R2, R3, R4 R5' R6 and R7 ,n, p and q are as defined above can be synthesized by using the general process described in synthetic scheme la.
General Scheme la



(R5)n

fcC£
R1

(R5)n

NHCOCH,



12

13a

13b




(R>
(R5)n

NH2 3
R'
14

Wherein the compound of general formula (12) can be reduced in the presence of reducing agents (such as sodium borohydride or borane) in a suitable solvent such as (THF ) to yield a compound of general formula (13a).The compound of general formula (13a) can then be converted to the compound of general formula (13b) followed by hydrolysis using a suitable base (such as sodium hydroxide) or acids (such as hydrochloric acid ) to yield the compound of general formula (14).The compound of general (14) can then be converted to the desired compound of general formula (I) using the process as described in Scheme 1
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Example 1
(±)l-{3,4-Dihydro-r-(methyl)spiro-[2H-l-benzopyran-2,4'-piperidine]-4-yl}-3-
(isoquinoline-5-yl)urea

Step I: 3,4-Dihydrospiro-r-methyI-2/T-l-benzopyran-2,4'-piperidine-4-one:A
solution of 2'-hydroxy acetophenone (10 mmol), JV-methylpiperidone (10 mmol) and pyrrolidine (20 mmol) in methanol was refluxed for 15h. The reaction mixture was then cooled to room temperature and concentrated in vacuum. The residue was dissolved in ethyl acetate and washed with sat. NaHCC>3 followed by 6N HCl. The HCl layer was separated and basified to pH 9. Product was extracted in ethyl acetate. Organic layer was separated, dried over anhydrous Na2S04 and concentrated in vacuum to afford the desired product in quantitative yield.
*H NMR (CDC13): 81.76 (2H, m, CH2); 2.04 (2H, m, CH2); 2.33 (3H, s, CH3); 2.43 (2H, t, J= 11.1); 2.60 (2H, m, CH2); 2.72 (2H, s, CH2); 7.22 (2H, m, 2 x ArH); 7.50 (1H, m, ArH); 7.86 (1H, dd, ./= 2.1 & 8.4 Hz).
Step II: 3,4-Dihydro-4-(hydroxyimino)-r-methyl-spiro-[2/7]-l-benzopyran-2,4'-piperidine : A solution of 3,4-Dihydrospiro-r-methyl-2H-l-benzopyran-2,4'-piperidine-4-one (10 mmol) and Hydroxylamine. HCl (15 mmol) in ethanol (20 ml) was refluxed for 5h in the presence of Sodium hydroxide (50 mmol in 5 ml water). The reaction mixture was then cooled to room temperature and treated with sat. NH4C1. 3,4-Dihydro-4-(hydroxyimino)-l'-methyl-spiro-[2//]-l-benzopyran-2,4'-piperidine separated in the form of a precipitate. It was then filtered and washed with water.
*H NMR (DMSO- d6): 81.57-1.77 (4H, m, 2 x CH2); 2.19 (3H, s, CH3); 2.28 (2H, t, J= 9.9); 2.46 (2H, m, CH2); 2.76 (2H, s, CH2); 6.91 (2H, m, 2 x ArH); 7.26 (1H, m, ArH); 7.74 (1H, d, J= 7.8 Hz); 11.29 (1H, s, OH).
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Step III: (±)4-Amino-3,4-Dihydrospiro-r-methyl-2//-l-benzopyran-2,4'-piperidine .ditrifluroacteate(2TFA): To a solution of 3,4-Dihydro-4-(hydroxyimino)-l'-methyl-spiro-[2//]-l-benzopyran-2,4'-piperidine (0.5g) in ethanol (10 ml) and aq. NaOH (2N, 10 ml), was added Ni-Al alloy (0.75g). The suspension was then stirred at room temperature for 15h. Reaction mixture was then filtered through a bed of celite and washed with ethanol. Ethanol was evaporated and the residue was taken in THF and treated with Boc anhydride (1.5 eq.). The desired compound was then extracted in ethyl acetate. Organic layer was separated, dried over anhydrous Na2S04 and concentrated in vacuum to afford a residue. The residue was dissolved in dichloromethane and treated with trfluoroacetic acid at room temperature for 24h. The solvent and trifluoroacetic acid was evaporated under vacuum to afford the desired 4-Amino-3,4-Dihydrospiro-l'-methyl-2H-l-benzopyran-2,4'-piperidine.2TFA in quantitative yield.
'H NMR (MeOH- d4): 51.81-2.15 (5H, m, 2 x CH2& CH); 2.30 (IH, dd, J= 13.2 & 6.6 Hz, CH); 2.84 (3H, s, CH3); 3.07 (IH, m, CH); 3.25 (IH, m, CH); 3.41 (2H, m, CH2); 4.61 (IH, dd, J= 6.9 & 11.1 Hz, CH); 6.96 (2H, m, 2 x ArH); 7.24 (IH, t, J= 7.5 Hz, ArH); 7.37 (lH, d, J =8.1 Hz).
Step IV: (±)l-{3,4-Dihydro-r-(methyl)spiro-[2H-l-benzopyran-2,4'-piperidine]-4-
yl}-3-(isoquinoline-5-yl)urea :A solution of phenyl N-(5-isoquinolinyl)carbamate (1
mmol) and 4-Amino-3,4-Dihydrospiro-l'-methyl-2H-l-benzopyran-2,4'-
piperidine. 2TFA (1 mmol) in DMSO was stirred in the presence of a base such as triethylamine (2 mmol). Few drops of water were added in the reaction mixture. The desired urea precipitated out, was filtered and washed with water
*H NMR (MeOH- d4): 81.62-1.87 (5H, m, 2 x CH2& CH); 2.12-2.34 (5H, m, 2 x CH & CH3); 2.56 (3H, m, CH & CH2); 5.08 (IH, dd, J= 6.6 & 10.8 Hz, CH); 6.73 (IH, d, J = 8.4 Hz, ArH); 6.84 (IH, t, J = 7.8 Hz, ArH); 7.08 (IH, t, J= 7.5 Hz, ArH); 7.29 (IH, d, J = 7.8 Hz, ArH); 7.59 (IH, t, J= 7.8 Hz, ArH); 7.78 (IH, d, J= 7.5 Hz, ArH); 7.84 (IH, d, J= 6.3 Hz, ArH); 8.09 (IH, d, J= 7.5 Hz, ArH); 8.36 (IH, d, J= 6.0 Hz, ArH); 9.13 (IH, s, ArH).:Melting point: 130°C: IR (KBr): 3341, 1698, 1551, 1234, 757.
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Example 2
(±)l-(2',3,3',4, 5',6'-Hexahydrospiro-[2H-l-benzopyran-2,4'-pyran]-4-yl)-3-
(isoquinoline-5-yl)urea

-o
Step I: 2',3, 3',4, 5',6'-Hexahydrospiro-[2//]-l-benzopyran-2,4'-[4//]pyran-4-one
:was synthesizes using the process described in Step-I of Example 1 with the diferrence being use of Pyranone instaesd of N-methylpiperidone and was used with out any purification .
Step II: 2',3, 3',4, 5\6'-Hexahydro-4-(hydroxyimino)-spiro-[2//]-l-benzopyran-2,4'-[4//]pyran ::was synthesizes using the process described in Step-II of Example 1 and used further with out any purification .
Step III: (±)4-Amino-2',3,3\4,5',6'-hexahydrospiro-[2/7]-l-benzopyran-2,4'-[4#]-pyran ::was synthesizes using the process as described in Step-Ill of Example 1 . !H NMR (CDC13): 81.68 - 1.90 (7H, m); 2.17 (IH, dd, J = 6.3 & 13.2 Hz); 3.76 - 3.88 (3H, m); 3.98 - 4.14 (2 H, m); 6.91 (IH, d, / = 8.1 Hz); 6.99 (IH, t, J = 6.0 Hz); 7.21 (IH, t, ./= 6.9 Hz); 7.48 (IH, d, 7.8 Hz).
Step IV: (±)l-(2\3,3\4, 5\6'-Hexahydrospiro-[2#-l-benzopyran-2,4'-pyran]-4-yl)-3-(isoquinoline-5-yl)urea :was synthesizes using the process as described in Step-IV of Example 1 .
'H NMR (CDC13): 51.72 - 1.85 (5H, m); 2.28 (IH, dd, J = 6.6 & 13.5 Hz); 3.61 - 3.79 (4H, m); 5.05 (IH, m); 6.87 (IH, d, J= 8.1 Hz); 6.94 (IH, t, J= 7.2 Hz); 7.01 (IH, d, J = 8.4 Hz); 7.19 (IH, t, J= 7.5 Hz); 7.35 (IH, d, J = 7.8 Hz); 7.63 (IH, t, J = 7.5 Hz); 7.77 (IH, d, J= 8.1 Hz); 7.93 (IH, d, J= 6.3 Hz); 8.36 (IH, d, J= 7.5 Hz); 8.55 (IH, d, J = 5.7 Hz); 8.73 (IH, s); 9.29 (IH, s);Melting point: 220°C; IR (KBr): 3323, 1635, 1560, 1483, 1236, 753.
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Example 3
(±)l-(3,4-Dihydrospiro[2H-l-benzopyran-2,l'-cyclobutan]-4-yl)-3-(isoquinolin-5-
yl)urea

Step I: 3, 4-Dihydrospiro-[2/7]-l-benzopyran-2,r-cyclobutane-4-one ; :was synthesizes using the process described in Step-I of Example 1 with the diferrence being use of Cyclobutanone instead of N-methylpiperidone
!H NMR (CDC13): 51.66- 1.79 (IH, m); 1.86 - 1.99 (IH, m); 2.13-2.21 (2H, m); 2.28
- 2.39 (2H, m); 2.90 (2H, s); 6.96 - 7.02 (2H, m); 7.48 (IH, t, J= 7.5 Hz); 7.85 (IH, d, J
= 7.8 Hz).
Step II: 3,4-Dihydro-4-(hydroxyimino)-spiro-[2//]-l-benzopyran-2,1-cyclobutane :
:was synthesizes using the process described in Step-II of Example 1
•H NMR (CDC13): 8 1.70 - 1.79 (IH, m); 1.82 - 1.97 (IH, m); 2.07 - 2.15 (2H, m); 2.22
- 2.37 (2H, m); 3.07 (2H, s); 6.89 - 6.95 (2H, m); 7.25 - 7.30 (2H, m); 7.77 (IH, d, J =
8.1 Hz).
Step III: (±) 4-Amino-3,4-Dihydrospiro-2H-l-benzopyran-2,l' cyclobutane. HCl: was
synthesizes using the process as described in Step-Ill of Example 1
!H NMR (DMSO-d6): S 1.67 - 1.2.36 (8H, m); 4.57 (IH, m); 6.85 (IH, d, J= 8.1 Hz);
6.98 (IH, t, J= 8.1 Hz); 7.26 (IH, d, J= 8.4 Hz); 7.59 (IH, d, J= 7.5 Hz); 8.73 (3H, b).
Step IV: (±) l-(3,4-Dihydrospiro[2H-l-benzopyran-2,l'-cyclobutan]-4-yl)-3-(isoquinolin-5-yl)urea :was synthesizes using the process as described in Step-IV of Example 1 .
*H NMR (DMSO-6): 8 1.73 - 1.97 (3H, m); 2.15 - 2.32 (4H, m); 2.42 (IH, m); 5.02 (IH, m); 6.82 (IH, d, J= 7.8 Hz); 6.93 (IH, t, J= 6.9 Hz); 7.04 (IH, d, J= 8.1 Hz); 7.18 (IH, t, J= 7.2 Hz); 7.31 (IH, d, J= 7.2 Hz); 7.62 (IH, t, J= 7.5 Hz); 7.77 (IH, d, J = 8.1
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Hz); 7.94 (IH, d, J = 6.0 Hz); 8.39 (IH, d, J= 7.5 Hz); 8.56 (IH, d, J- 6.0 Hz); 8.74 (IH, s); 9.29 (IH, s);Melting Point: 246°C; IR (KBr): 3326, 3277, 1627, 1563, 1239, 753.
Screening for TRPV1 antagonist using the 45Calcium uptake assay:
The inhibition of TRPV1 receptor activation was followed as inhibition of capsaicin induced cellular uptake of radioactive calcium which represents calcium influx exclusively through the plasma membrane associated TRPV1 receptor. Materials:
Stock solution of capsaicin was made in ethanol and test compounds in 100 % DMSO. Stock solutions were diluted to appropriate final concentrations in assay buffer keeping the final DMSO concentration between 0.1% and 0.55%.
45Ca was used at a final concentration of 2.5 uCi/ml (45Ca, ICN).
Assay buffer was composed of F-12 DMEM medium supplemented with 1.8 mM CaCl2 (final cone.) and 0.1 % Bovine serum albumin.(BSA from SIGMA)
Wash buffer was tyrodes solution supplemented with 0.1% BSA and 1.8 mM calcium. Lysis buffer contained 50 mM Tris-HCl, pH7.5, 150 mM NaCl, 1% Triton X-100, 0.5% deoxycholate and 0.1% Sodium dodicyl sulphate (SDS, SIGMA)
Method:
Assay was carried out with some modifications the of procedure as described by Toth et.al.( See Toth A et. al, Life Sciences 73 p 487-498 ,200J)._Human TRPV1 expressing CHO cells were grown in F-12 DMEM (Dulbecco's modified Eagle's medium -GIBCO ) medium with 10% FBS( fetal bovine serum Hyclone), 1% penicillin-streptomycin solution, 400 μg I ml of G-418. Cells were seeded 48 h prior to the assay in 96 well plates so as to get ~ 50,000 cells per well on the day of experiment. Plates were incubated at 37°C in the presence of 5 % CO2. Cells were then washed twice with 200 μl of assay buffer and re-suspended in 144 \x\ of the same. Assay was carried out at 30°C in total volume of 200 μl. Test compounds were added to the cells fifteen minutes before addition of capsaicin. Final concentration of capsaicin in the assay was 250 nM. After 5 minutes of agonist treatment, drug was washed out and wells rinsed with 300 μl of ice cold wash buffer 3X. The cells were lysed in 50 μl lysis buffer for 20 min. 40 μl of cell lysate was mixed with 150 μl of Microscint PS, left overnight for equilibration. Radioactivity in samples was measured as counts per
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minute (cpm) using Packard Biosciences Top Count. The drug / vehicle / capsaicin treated 45Ca uptake values were normalized over basal 45Ca value. Data was expressed as % inhibition of 45Ca uptake by test compound with respect to maximum 45Ca uptake induced by capsaicin alone. IC50 value was calculated from dose response curve by nonlinear regression analysis using GraphPadPRISM software.
Results are as summarized in the table

Example No. % inhibition of 45Ca uptake at 1 μM IC50 nM
1 142.29 -
2 96.12 170.8
3 100 2.89
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as described above.
All publications and patent applications cited in this application are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated herein by reference.
Dated this Seventh (7th) day of October 2005

Glenn Saldanha President
Glenmark Pharmaceuticals S.A.
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Patent Number 256976
Indian Patent Application Number 1629/MUM/2005
PG Journal Number 34/2013
Publication Date 23-Aug-2013
Grant Date 21-Aug-2013
Date of Filing 28-Dec-2005
Name of Patentee CADILA PHARMACEUTICALS LTD.
Applicant Address "CADILA CORPORATE CAMPUS", SARKHEJ-DHOLKA ROAD, BHAT, AHMEDABAD 382 210.
Inventors:
# Inventor's Name Inventor's Address
1 PONNAIAH RAVI CADILA PHARMACEUTICALS LTD., "CADILA CORPORATE CAMPUS", SARKHEJ-DHOLKA ROAD, BHAT, AHMEDABAD 382 210.
2 DIVAKARA SOMAYAJULU NORI CADILA PHARMACEUTICALS LTD., "CADILA CORPORATE CAMPUS", SARKHEJ-DHOLKA ROAD, BHAT, AHMEDABAD 382 210.
3 MADHUSUDANA RAO GAJULA CADILA PHARMACEUTICALS LTD., "CADILA CORPORATE CAMPUS", SARKHEJ-DHOLKA ROAD, BHAT, AHMEDABAD 382 210.
4 KUNJARU N. SHASHIKALA CADILA PHARMACEUTICALS LTD., "CADILA CORPORATE CAMPUS", SARKHEJ-DHOLKA ROAD, BHAT, AHMEDABAD 382 210.
5 SANTOSH M. RUDRAMUNI CADILA PHARMACEUTICALS LTD., "CADILA CORPORATE CAMPUS", SARKHEJ-DHOLKA ROAD, BHAT, AHMEDABAD 382 210.
6 BAKULESH MAFATLAL KHAMAR CADILA PHARMACEUTICALS LTD., "CADILA CORPORATE CAMPUS", SARKHEJ-DHOLKA ROAD, BHAT, AHMEDABAD 382 210.
7 INDRAVADAN AMBALAL MODI CADILA PHARMACEUTICALS LTD., "CADILA CORPORATE CAMPUS", SARKHEJ-DHOLKA ROAD, BHAT, AHMEDABAD 382 210.
8 JAYARAMAN VENKATRAMAN CADILA PHARMACEUTICALS LTD., "CADILA CORPORATE CAMPUS", SARKHEJ-DHOLKA ROAD, BHAT, AHMEDABAD 382 210.
9 GURUSAMY RENUGADEVI CADILA PHARMACEUTICALS LTD., "CADILA CORPORATE CAMPUS", SARKHEJ-DHOLKA ROAD, BHAT, AHMEDABAD 382 210.
PCT International Classification Number C07C 235/44
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA