Title of Invention

IMIDAZOPYRIDINE INTERMEDIATES

Abstract The invention relates to compounds of the formula (I), in which the substituents and symbols have the meanings indicated in the description. The compounds are valuable intermediates for the preparation of pharmaceutical active compounds.
Full Text FORM 2
THE PATENT ACT 1970 (39 of 1970)
&
The Patents Rules, 2003
PROVISIONAL / COMPLETE SPECIFICATION (See Section 10, and rule 13)
TITLE OF INVENTION IMIDAZOPYRIDINE INTERMEDIATES
APPLICANT(S)
a) Name : ALTANA PHARMA AG
b) Nationality : GERMAN Company
c) Address : BYK-GULDEN-STRASSE 2,
78467 KONSTANZ,
GERMANY
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

Imidazopyridine Intermediates
Technical field
The invention relates to novel compounds which are used in the pharmaceutical industry as valuable intermediates for the preparation of active compounds.
Prior art
The international patent applications WO 98/54188, WO 01/72756, WO 01/72754, WO 01/72755, WO 01/72757, WO 02/34749, WO 03/016310, WO 03/014120 and WO 03/014123 disclose tricyclic imidazopyridine derivatives having a very specific substitution pattern, which should be suitable for the treatment of gastric and intestinal disorders, and certain processes for their preparation. In the document Drugs Fut 2001, 26 (6), 590, the preparation of tetrahydrobenzopyranes by cyclization using ortho-esters is disclosed.
Description of the Invention
The invention relates to a new process for the production of the tricyclic imidazopyridine derivatives mentioned above, and to valuable intermediates used in said processes.
The invention thus relates in a first aspect to compounds of the formula 1

Rl is hydrogen, l-4C-alkyl, 3-7C-cycloalkyl, 3-7C-cycloalkyl-l-<-alkyl l-4c-alkoxy> alkoxy- l-4C-alkyl, l-4C-alkoxycarbonyl, 2-4C-aIkenyl, 2-4C-alkynyl, fluoro-l-4C-alkyl or
hydroxy-1 -4C-alky 1, R2 is hydrogen, l-4C-alkyl, aryl, 3-7C-cycloalkyl, 3-7C-cycloalkyl-l-4C-alkyl, 1-4C-
alkoxycarbonyl, hydroxy-l-4C-alkyl, halogen, 2-4C-alkenyl, 2-4C-alkynyI, fluoro-l-4C-alkyl,
cyanomethyl
2

R3a is hydrogen, halogen, fluoro-l-4C-alkyl, l-4C-aIkyl, 2-4C-alkenyl, 2-4C-alkynyl, carboxyl, 1-4C-alkoxycarbonyl, hydroxy-l-4C-alkyl, l-4C-alkoxy-l-4C-alkyl, l-4C-alkoxy-l-4C-alkoxy-l-4C-alkyl, fluoro-l-4C-alkoxy-l-4C-alkyl or the radical -CO-NR31R32, R3b is hydrogen, halogen, fluoro-l-4C-alkyl, l-4C-alkyl, 2-4C-alkenyl, 2-4C-alkynyl, carboxyl, 1-4C-alkoxycarbonyl, hydroxy-l-4C-alkyl, l-4C-alkoxy-l-4C-aIkyl, l-4C-alkoxy-l-4C-alkoxy-l-4C-alkyl, fluoro-l-4C-alkoxy-l-4C-alkyl or the radical -CO-NR31R32, where
R31 is hydrogen, l-7C-alkyl, hydroxy-l-4C-alkyI or l-4C-alkoxy-lC-alkyl and R32 is hydrogen, l-7C-alkyI, hydroxy-l-4C-alkyl or l-4C-alkoxy-l-4C-alkyl, or where
R31 and R32 together, including the nitrogen atom to which both are bonded, are a pyrrolidino, piperidino, piperazino, N-l-4C-alkylpiperazino or morpholino radical, Arom is a mono- or bicyclic aromatic radical substituted by R4, R5, R6 and R7, which is selected from the group consisting of phenyl, naphthyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, indolyl, benzimidazolyl, furanyl (furyl), benzofuranyl (benzofuryl), thiophenyl (thienyl), benzothiophenyl (benzothienyl), thiazolyl, isoxazolyl, pyridinyl, pyrimidinyl, quinolinyl and isoquinolinyl, where
R4 is hydrogen, l-4C-alkyl, hydroxy-l-4C-alkyl, l-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, l-4C-alkoxycarbonyl, carboxy-l-4C-alkyl, l-4C-alkoxycarbonyl-l-4C-alkyl, halogen, hydroxyl, aryl, aryl-l-4C-alkyl, aryloxy, aryl-l-4C-alkoxy, trifluoromethyl, nitro, amino, mono- or di-l-4C-alkylamino, l-4C-alkylcarbonyIamino, 1-4C-alkoxycarbonylamino, l-4C-alkoxy-l-4C-alkoxycarbonylamino or sulfonyl,
R5 is hydrogen, l-4C-alkyl, l-4C-alkoxy, l-4C-alkoxycarbonyl, halogen, trifluoromethyl or
hydroxyl, R6 is hydrogen, l-4C-alkyl or halogen and R7 is hydrogen, l-4C-alkyl or halogen, where
aryl is phenyl or substituted phenyl having one, two or three identical or different substituents from the group consisting of l-4C-alkyl, l-4C-alkoxy, carboxyl, l-4C-alkoxycarbonyl, halogen, trifluoromethyl, nitro, trifluoromethoxy, hydroxyl and cyano, and their salts.
1-4C-Alkyl represents straight-chain or branched alkyl radicals having 1 to 4 carbon atoms. Examples which may be mentioned are the butyl, isobutyl, sec-butyl, tert-butyl, propyl, isopropyl, ethyl and the methyl radical.
3

3-7C-Cycloalkyl represents cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl, of which cyclopropyl, cyclobutyl and cyclopentyl are preferred.
3-7C-Cycloalkyl-l-4C-alkyl represents one of the aforementioned l-4C-alkyl radicals, which is substituted by one of the aforementioned 3-7C-cycloalkyl radicals. Examples which may be mentioned are the cyclopropylmethyl, the cyclohexylmethyl and the cyclohexylethyl radical.
l-4C-Alkoxy represents radicals, which in addition to the oxygen atom contain a straight-chain or branched alkyl radical having 1 to 4 carbon atoms. Examples which may be mentioned are the butoxy, isobutoxy, sec-butoxy, tert-butoxy, propoxy, isopropoxy and preferably the ethoxy and methoxy radical.
l-4C-Alkoxy-l-4C-alkyl represents one of the aforementioned l-4C-alkyl radicals, which is substituted by one of the aforementioned l-4C-alkoxy radicals. Examples which may be mentioned are the methoxymethyl, the methoxyethyl radical and the butoxyethyl radical.
l-4C-Alkoxycarbonyl represents a carbonyl group, to which one of the aforementioned l-4C-alkoxy radicals is bonded. Examples which may be mentioned are the methoxy carbonyl (CH30-C(0)-) and the ethoxycarbonyl radical (CH3CH20-C(0)-).
2-4C-AlkenyI represents straight-chain or branched alkenyl radicals having 2 to 4 carbon atoms. Examples which may be mentioned are the 2-butenyl, 3-butenyl, 1-propenyl and the 2-propenyl radical (allyl radical).
2-4C-Alkynyl represents straight-chain or branched alkynyl radicals having 2 to 4 carbon atoms. Examples which may be mentioned are the 2-butynyl, 3-butynyl, and preferably the 2-propynyl, radical (propargyl radical).
Fluoro-l-4C-alkyl represents one of the aforementioned l-4C-alkyl radicals, which is substituted by one or more fluorine atoms. An example which may be mentioned is the trifluoromethyl radical.
Hydroxy-l-4C-alkyl represents aforementioned l-4C-alkyl radicals, which are substituted by a hydroxy group. Examples which may be mentioned are the hydroxymethyl, the 2-hydroxyethyI and the 3-hydroxypropyl radical.
Halogen within the meaning of the invention is bromo, chloro and fluoro.
4

l-4C-Alkoxy-l-4C-alkoxy represents one of the aforementioned l-4C-alkoxy radicals, which is substituted by a further l-4C-alkoxy radical. Examples which may be mentioned are the radicals 2-(methoxy)ethoxy (CH3-O-CH2-CH2-O-) and 2-(ethoxy)ethoxy (CH3-CH2-O-CH2-CH2-O-).
l-4C-Alkoxy-l-4C-alkoxy-l-4C-alkyl represents one of the aforementioned l-4C-alkoxyl-4Calkyl radicals, which is substituted by one of the aforementioned l-4C-alkoxy radicals. An example which may be mentioned is the radical 2-(methoxy)ethoxy-methyl (CH3-O-CH2-CH2O-CH2-).
Fluoro-l-4C-alkoxy-l-4C-alkyl represents one of the aforementioned l-4C-alkyl radicals, which is substituted by a fluoro-l-4C-alkoxy radical. Fluoro-l-4C-alkoxy in this case represents one of the aforementioned l-4C-alkoxy radicals, which is wholly or mainly substituted by fluorine. Examples of wholly or mainly fluoro-substituted l-4C-alkoxy which may be mentioned are the 1,1,1,3,3,3-hexafluoro-2-propoxy, the 2-trifluoromethyl-2-propoxy, the l,l,l-trifluoro-2-propoxy, the perfluoro-tert-butoxy, the 2,2,3,3,4,4,4-heptafluoro-l-butoxy, the 4,4,4-trifluoro-l-butoxy, the 2,2,3,3,3-pentafluoropropoxy, the perfluoroethoxy, the 1,2,2-trifluoroethoxy, in particular the 1,1,2,2-tetrafluoroethoxy, the 2,2,2-trifluoroethoxy, the trifluoromethoxy and preferably the difluoromethoxy radical.
1-7C-Alkyl denotes straight-chain or branched alkyl radicals having 1 to 7 carbon atoms. Examples which may be mentioned are the heptyl, isoheptyl-(5-methylhexyI), hexyl, isohexyl-(4-methylpentyl), neohexyl-(3,3-dimethylbutyl), pentyl, isopentyl-(3-methylbutyl), neopentyl-(2,2-dimethylpropyl), butyl, isobutyl, sec-butyl, tert-butyl, propyl, isopropyl, ethyl and methyl radicals.
2-4C-Alkenyloxy represents a radical, which in addition to the oxygen atom contains a 2-4C-alkenyl radical. An example which may be mentioned is the allyloxy radical.
l-4C-Alkylcarbonyl represents a radical, which in addition to the carbonyl group contains one of the aforementioned l-4C-alkyl radicals. An example which may be mentioned is the acetyl radical.
Carboxy-l-4C-alkyl for example represents the carboxymethyl (-CH2COOH) or the carboxyethyl radical (-CCH2COOH).
l-4C-Alkox Hycarbonyl-l-4C-alkyl represents one of the aforementioned l-4C-alkyl radicals, which is substituted by one of the aforementioned l-4C-alkoxycarbonyl radicals. An example which may be mentioned is the ethoxycarbonylmethyl radical (CH3CH20C(0)CH2-).
5

Aryl-l-4C-alkyl represents an aryl-substituted l-4C-alkyl radical. An example which may be mentioned is the benzyl radical.
Aryl-l-4C-alkoxy represents an aryl-substituted l-4C-alkoxy radical. An example which may be mentioned is the benzyloxy radical.
Mono- or di-l-4C-alkylamino radicals contain, in addition to the nitrogen atom, one or two of the aforementioned l-4C-alkyl radicals. Di-l-4C-alkylamino is preferred and here, in particular, dimethyl-, diethyl- or diisopropylamino.
l-4C-AlkyIcarbonylamino represents an amino group to which a l-4C-alkylcarbonyl radical is bonded. Examples which may be mentioned are the propionylamino (C3H7C(0)NH-) and the acetylamino radical (acetamido radical) (CH3C(0)NH-).
l-4C-Alkoxycarbonylamino represents an amino radical, which is substituted by one of the aforementioned l-4C-alkoxycarbonyl radicals. Examples which may be mentioned are the ethoxy-carbonylamino and the methoxycarbonylamino radical.
l-4C-Alkoxy-l-4C-alkoxycarbonyl represents a carbonyl group, to which one of the aforementioned l-4C-alkoxy-l-4C-alkoxy radicals is bonded. Examples which may be mentioned are the 2-(methoxy)ethoxycarbonyl (CH3-O-CH2CH2-O-CO-) and the 2-(ethoxy)ethoxy-carbonyl radical (CH3CH2-O-CH2CH2-O-CO-).
l-4C-Alkoxy-l-4C-alkoxycarbonyIamino represents an amino radical, which is substituted by one of the aforementioned l-4C-alkoxy-l-4C-alkoxycarbonyl radicals. Examples which may be mentioned are the 2-(methoxy)ethoxycarbonylamino and the 2-(ethoxy)ethoxycarbonyl-amino radical.
Arom radicals which may be mentioned are, for example, the following substituents: 4-acetoxy-
phenyl, 4-acetamidophenyl, 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxy phenyl, 3-ben-
zyloxyphenyl, 4-benzyloxyphenyl, 3-benzyloxy-4-methoxyphenyl, 4-benzyloxy-3-methoxyphenyl,
3,5-bis(trifluoromethyl) phenyl, 4-butoxyphenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 2-
chloro-6-fluorophenyl, 3-chloro-4-fluorophenyl, 2-chloro-5-nitrophenyl/ 4-chloro-3-nitrophenyl, 3-
(4-chlorophenoxy)phenyl, 2,4-dichlorophenyl, 3,4-difluorophenyl, 2,4-dihydroxy phenyl, 2,6-
dimethoxyphenyl, 3,4-dimethoxy-5-hydroxyphenyl, 2,5-dimethylphenyl, 3-ethoxy-4-
hydroxyphenyl, 2-fluorophenyl, 4-fluorophenyl, 4-hydroxyphenyl, 2-hydroxy-5-nitrophenyl, 3-methoxy-2-nitrophenyl, 3-nitrophenyl, 2,3,5-trichlorophenyl, 2,4,6-trihydroxyphenyI, 2,3,4-trimethoxyphenyl, 2-hydroxy-l-naphthyl, 2-methoxy-l-naphthyl, 4-methoxy-l-naphthyI, 1-methyl-
6

2-pyrrolyl, 2-pyrrolyl, 3-methyl-2-pyrrolyl, 3,4-dimethyl-2-pyrrolyl, 4-(2-methoxycarbonylethyl)-3-
methyl-2-pyrrolyl, 5-ethoxycarbonyl-2,4-dimethyl-3-pyrrolyI, 3,4-dibromo-5-methyl-2-pyrrolyl, 2,5-
dimethyl-l-phenyl-3-pyrrolyl, 5-carboxy-3-ethyl-4-methyl-2-pyrrolyl, 3,5-dimethyl-2-pyrrolyl, 2,5-
dimethyl-l-(4-trifluoromethylphenyI)-3-pyrrolyl, l-(2,6-dichloro-4-trifluoromethylphenyI)-2-
pyrrolyl, l-(2-nitrobenzyl)-2-pyrrolyl, l-(2-fluorophenyI)-2-pyrrolyl, l-(4-trifluoromethoxyphenyl)-
2-pyrroIyI, l-(2-nitrobenzyl)-2-pyrrolyl, l-(4-ethoxycarbonyl)-2,5-dimethyl-3-pyrrolyl, 5-chloro-l,3~
dimethyl-4-pyrazolyl, 5-chloro-l-methyl-3-trifluoromethyl-4-pyrazolyl, l-(4-chlorobenzyl)-5-
pyrazolyl, l,3-dimethyl-5-(4-chlorphenoxy)-4-pyrazolyl, l-methyl-3-trifluomethyl-5-(3-
trifluoromethylphenoxy)-4-pyrazolyl, 4-methoxycarbonyl-l-(2,6-dichlorophenyl)-5-pyrazolyl, 5-allyIoxy-l-methyl-3-trifluoromethyl-4-pyrazolyl, 5-chloro-l-phenyl-3-trifluoromethyl-4-pyrazolyl, 3,5-dimethyl-l-phenyl-4-imidazolyl, 4-bromo-l-methyl-5-imidazolyl, 2-butylimidazolyl, l-phenyl-l,2,3-triazol-4-yl, 3-indolyl, 4-indolyl, 7-indolyl, 5-methoxy-3-indolyl, 5-benzyIoxy-3-indoIyl, 1-benzyl-3-indolyl, 2-(4-chlorophenyl)-3-indolyl, 7-benzyIoxy-3-indolyl, 6-benzyloxy-3-indolyl, 2-methyl-5-nitro-3-indolyl, 4,5,6,7-tetrafluoro-3-indolyl, l-(3,5-difluorobenzyl)-3-indolyl, l-methyl-2-(4-trifluorophenoxy)-3-indolyl, l-methyl-2-benzimidazolyl, 5-nitro-2-furyl, 5-hydroxymethyl-2-furyl, 2-furyl, 3-furyl, 5-(2-nitro-4-trifluoromethylphenyl)-2-furyI, 4-ethoxycarbonyl-5-methyl-2-furyl, 5-(2-trifluoromethoxyphenyl)-2-furyl, 5-(4-methoxy-2-nitrophenyl)-2-furyl, 4-bromo-2-furyl, 5-dimethylamino-2-furyl, 5-bromo-2-furyl, 5-sulfo-2-furyl, 2-benzofuryI, 2-thienyl, 3-thienyl, 3-methyl-2-thienyl, 4-bromo-2-thienyI, 5-bromo-2-thienyl, 5-nitro-2-thienyl, 5-methyI-2-thienyI, 5-(4-methoxyphenyl)-2-thienyl, 4-methyl-2-thienyl, 3-phenoxy-2-thienyl, 5-carboxy-2-thienyl, 2,5-dichloro-3-thienyl, 3-methoxy-2-thienyl, 2-benzothienyl, 3-methyl-2-benzothienyl, 2-bromo-5-chloro-3-benzothienyl, 2-thiazolyl, 2-amino-4-chloro-5-thiazolyl, 2,4-dichloro-5-thiazolyl, 2-diethylamino-5-thiazolyl, 3-methyl-4-nitro-5-isoxazolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 6-methyl-2-pyridyl, 3-hydroxy-5-hydroxymethyl-2-methyl-4-pyrxdyl, 2,6-dichloro-4-pyridyl, 3-chloro-5-trifluoromethyl-2-pyridyl, 4,6-dimethyl-2-pyridyl, 4-(4-chlorophenyl)-3-pyridyl, 2-chloro-5-methoxycarbonyl-6-methyl-4-phenyl-3-pyridyl, 2-chloro-3-pyridyl, 6-(3-trifluoromethylphenoxy)-3-pyridyl, 2-(4-chlorophenoxy)-3-pyridyl, 2,4-dimethoxy-5-pyrimidinyl, 2-quinolinyl, 3-quinolinyl, 4-quinolinyl, 2-chloro-3-quinolinyl, 2-chloro-6-methoxy-3-quinolinyl, 8-hydroxyl-2-quinolinyl and 4-isoquinolinyl.
Possible salts of compounds of the formula I - depending on substitution - are especially all acid addition salts. Particular mention may be made of the pharmacologically tolerable salts of the inorganic and organic acids customarily used in pharmacy. Those suitable are water-soluble and water-insoluble acid addition salts with acids such as, for example, hydrochloric acid, hydrobromic acid, phosphoric acid, nitric acid, sulfuric acid, acetic acid, citric acid, D-gluconic acid, benzoic acid, 2-(4-hydroxybenzoyl)benzoic acid, butyric acid, sulfosalicylic acid, maleic acid, lauric acid, malic acid, fumaric acid, succinic acid, oxalic acid, tartaric acid, embonic acid, stearic acid, toluenesulfonic acid, methanesulfonic acid or 3-hydroxy-2-naphthoic acid, where the acids are used in salt
7

preparation - depending on whether a mono- or polybasic acid is concerned and on which salt is desired - in an equimolar quantitative ratio or one differing therefrom.
It is known to the person skilled in the art that the compounds according to invention and their salts, if, for example, they are isolated in crystalline form, can contain various amounts of solvents. The invention therefore also comprises all solvates and in particular all hydrates of the compounds of the formula I, and also all solvates and in particular all hydrates of the salts of the compounds of the formula I.
The compounds of the formula 1 have two chiral centers in the parent structure. The invention thus relates to all conceivable stereoisomers in any desired mixing ratio to one another, including the pure enantiomers, which are a preferred subject of the invention.
One embodiment (embodiment 1) of the invention are compounds of the formula 1, in which
Rl is l-4C-alkyl and
R2, R3a, R3b and Arom have the meanings as described in the outset.
Another embodiment (embodiment 2) of the invention are compounds of the formula 1, in which
R2 is l-4C-alkyl and
Rl, R3a, R3b and Arom have the meanings as described in the outset.
Another embodiment (embodiment 3) of the invention are compounds of the formula 1, in which
R3a is hydrogen and
Rl, R2, R3b and Arom have the meanings as described in the outset.
Another embodiment (embodiment 4) of the invention are compounds of the formula 1, in which
R3b is hydrogen and
Rl, R2, R3a and Arom have the meanings as described in the outset.
Another embodiment (embodiment 5) of the invention are compounds of the formula 1, in which
Arom is phenyl and
Rl, R2, R3a and R3b have the meanings as described in the outset.
Compounds to be emphasized are those of the formula 1, in which
Rl is hydrogen, l-4C-alkyl, 3-7C-cycloalkyl, l-4C-alkoxy-l-4C-alkyl, 2-4C-alkynyl or fluoro-l-4C-
alkyl, R2 is hydrogen, l-4C-alkyl, aryl, hydroxy-l-4C-alkyl, halogen, 2-4C-alkenyl, 2-4C-alkynyl,
fluoro-l-4C-alkyl
8

R3a is hydrogen,
R3b is hydrogen, halogen, l-4C-alkyl or the radical -CO-NR31R32,
where
R31 is hydrogen, l-7C-alkyl, hydroxy-l-4C-alkyl or l-4C-alkoxy-l-4C-alkyl and
R32 is hydrogen, l-7C-alkyl, hydroxy-l-4C-alkyl or l-4C-alkoxy-l-4C-alkyl,
or where
R31 and R32 together, including the nitrogen atom to which both are bonded, are a
pyrrolidino, piperidino or morpholino radical, Arom is a monocyclic aromatic radical substituted by R4, R5, R6 and R7, which is selected from the
group consisting of phenyl, furanyl (furyl) and thiophenyl (thienyl),
where
R4 is hydrogen, l-4C-alkyl, hydroxy-l-4C-alkyl, l-4C-alkoxy, l-4C-alkylcarbonyl, carboxyl, l-4C-alkoxycarbonyl, halogen, hydroxyl, trifruoromethyl, l-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, l-4C-alkoxy-l-4C-alkoxycarbonylamino or sulfonyl,
R5 is hydrogen, l-4C-alkyl, l-4C-alkoxy, l-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl,
R6 is hydrogen and
R7 is hydrogen, and their salts.
Compounds to be particularly emphasized are those of the formula 1, in which
Rl is l-4C-alkyl or l-4C-alkoxy-l-4C-alkyl,
R2 is hydrogen, l-4C-alkyl, phenyl, hydroxy-l-4C-alkyl or halogen
R3a is hydrogen,
R3b is hydrogen,
Arom is phenyl, furanyl (furyl) or thiophenyl (thienyl),
and their salts.
Among the compounds according to the invention, including the embodiments 1 to 5 and the compounds to be emphasized and to be particularly emphasized, the optically pure compounds of the formula 1*
9


are preferred.
Preferred compounds of the formula 1* are those in which
Rl is hydrogen, l-4C-alkyl, 3-7C-cycloalkyl, l-4C-alkoxy-l-4C-alkyl, 2-4C-alkynyl or fluoro-l-4C-
alkyl, R2 is hydrogen, l-4C-alkyl, aryl, hydroxy-l-4C-alkyl, halogen, 2-4C-alkenyl, 2-4C~alkynyl,
fluoro-l-4C-alkyl R3a is hydrogen, R3b is hydrogen, halogen, l-4C-alkyl or the radical -CO-NR31R32,
where
R31 is hydrogen, l-7C-alkyl, hydroxy-l-4C-alkyl or l-4C-alkoxy-l-4C-alkyl and
R32 is hydrogen, l-7C-alkyl, hydroxy-l-4C-alkyl or l~4C-alkoxy-l-4C-alkyl,
or where R31 and R32 together, including the nitrogen atom to which both are bonded, are a pyrrolidino,
piperidino or morpholino radical Arom is phenyl, furanyl (furyl) or thiophenyl (thienyl), and their salts.
Compounds with exemplary substituents to be particularly emphasized are those of the formula 1*,
in which
Rl is hydrogen, methyl, cyclopropyl, methoxymethyl or trifluoromethyl,
R2 is hydrogen, methyl, phenyl, hydroxymethyl, fluoro, chloro, bromo, ethynyl, trifluoromethyl
R3a is hydrogen,
R3b is hydrogen, fluorine, methyl or the radical -CO-N(CH3)2,
Arom is a phenyl radical
and their salts.
Particularly preferred exemplary compounds of the formula 1* are those, in which Rl is methyl,
R2 is hydrogen, methyl, fluoro, chloro, bromo, hydroxymethyl or trifluoromethyl
10

R3a is hydrogen, R3b is hydrogen, Arom is a phenyl radical and their salts.
Particularly preferred are the compounds given as final products in the examples, and their salts.
The invention further relates to the use of compounds of the formula 1, in which Rl, R2, R3a, R3b and Arom have the meanings indicated in the outset, for the preparation of compounds of the formula 2

in which Rl, R2, R3a, R3b and Arom have the meanings indicated in the outset, and R8 is hydrogen, 1-4C-Alkyl or aryl, as indicated in the outset, and their salts.
The preparation of the compounds of the formula 2 is effected, as shown for example in scheme 1, such that the compounds of the formula 1, in which Rl, R2, R3a, R3b and Arom have the meanings indicated in the outset, are reacted with ortho-esters R8-C(OR9)3, in which R8 is hydrogen, 1-4C-Alkyl or aryl, as indicated in the outset, and R9 is l-4C-alkyl.
11


To be emphasized according to the invention is the use of compounds of the formula 1* for the preparation of compounds of the formula 2*,

in which Rl, R2, R3a, R3b and Arom have the meanings indicated in the outset and R8 has the meaning hydrogen, 1-4C-Alkyl or aryl, as indicated in the outset, and their salts.
The conversion of a compound of the formula 1 into a cyclization product of the formula 2 according to scheme 1 is carried out in a manner known to the expert, e.g. similar to that disclosed in Drugs Fut 2001, 26 (6), 590.
12

The compounds of the formula 1 according to the invention, in which Rl, R2, R3a, R3b and Arom have the meanings indicated in the outset, can be prepared from the compounds of the formula 3, in which Rl, R2, R3a, R3b and Arom have the meanings indicated in the outset,



as shown by way of example in scheme 2 below for the compounds 1* and 3*, by reaction wit mineral acid:

Prefe
rred mineral acids for the reaction shown in scheme 2 are phosphoric acid, hydrochloric acid or sulphuric acid.
Starting compounds of the formula 3 are known (see WO 01/72755 or WO 02/34749) or they can be prepared in a known manner in analogy to known compounds as shown by way of example for the compound 3* in scheme 3 below.
13


The group X in scheme 3 is a suitable leaving group, for example a halogen atom, preferably chlorine, or a 1-4C alkoxy group, preferably methoxy.
The following examples serve to explain the invention in greater detail without restricting it. Likewise, further compounds of the formula 1, whose preparation is not described explicitly, can be prepared in an analogous manner or in a manner familiar per se to the person skilled in the art using customary process techniques. The abbreviation min stands for minute(s), h for hour(s) and m. p. for melting point.
14

Examples
Compounds of the formula 1
1. 2-Methyl-7-[(2R/3S)-2,3-diyhdroxy-3-phenylpropan-l-on-l-yl]imidazo[l/2-a]-pyridin-8-ol
156 g (0.442 mol) of 2-Methyl-7-[(2R/3S)-2,3-0/0-isopropyliden-2/3-dioxy-3-phenylpropan-l-on-l-yl]imidazo[l,2-a]-pyridin-8-ol are dissolved in 31 of 6 molar hydrochloric acid during 30 min. After stirring for 1 h at room temperature, the reaction mixture is cooled with an ice bath and neutralized to pH 6.5 to 7 using a 6 molar sodium hydroxide solution. The precipitate is filtered off, washed with water and for the most part redissolved in 0.5 molar hydrochloric acid. The remaining residue is separated by filtration and the filtrate is neutralized again to pH 6.5 to 7 using a 6 molar sodium hydroxide solution. The resulting precipitate is filtered off and dried in vacuum to afford 84.6 g (0.271 mol, yield 61 %) of the title compound in analytical pure quality as a beige-brown solid, m. p.: 110-115°C (water)
2. 2,3-Dimethyl-7-[{2R/3S)-2,3-diyhdroxy-3-phenylpropan-l-on-l-yl]imidazo[l,2-a]-pyridin-8-oI
l0g (0.027 mol) of 2,3-Dimethyl-7-[(2R,3S)-2,3-0,0-isopropyliden-2,3-dioxy-3-phenylpropan-l-on-l-yl]imidazo[l,2-a]-pyridin-8-ol are dissolved in 50 ml of 6 molar hydrochloric acid. After stirring for 30 min at room temperature, the reaction mixture is cooled with an ice bath and neutralized to pH 6.5 using a 6 molar sodium hydroxide solution. The resulting residue is filtered off, washed with water and dried in vacuum at 55 °C. The crude product is purified by chromatography on silica gel (eluent dichloromethane / methanol : 5 / 1) to give 5.77 g (0.018 mol, yield 65 %) of the title compound as ochre crystals.
iH-NMR (CDCI3): □ (ppm) = 2.25 (3H, s), 2.38' (3H, s), 5.32 (1H, d), 5.55 (1H, d), 7.13 (1H, d), 7.18 -7.25 (3H, m), 7.51 (2H, dd), 7.70 (1H, d).
Use of compounds of the formula 1 according to the invention for the preparation of compounds of the formula 2
A. (8R,9R)-8-Acetoxy-2-methyl-9-phenyl-7H-8,9-dihydro-pyrano[2,3-c]imidazo[1,2-a]-pyridin-7-on
150 ml (1.166 mol) of orthoacetic acid trimethyl ester, 7.5 g (0.030 mol) of pyridinium-p-toluenesulfonate and 13.5 ml (0.358 mol) of formic acid are added at room temperature to a solution of 93.4g (0.299 mol) of 2-Methyl-7-[(2R,3S)-2,3-diyhdroxy-3-phenylpropan-l-on-l-yl]imidazo-[l,2-a]-pyridin-8-ol in 2.31 of dichloromethane. After 2 h stirring at room temperature
15

the reaction mixture is poured onto 1.5 1 of a 0.25 molar sodium bicarbonate solution. After 15 min stirring at room temperature the organic phase is seperated and the aqueous phase extracted with methylene chloride. The combined organic layers are washed with saturated sodium bicarbonate solution, dried over sodium sulphate and the solvent removed under vacuum. The resulting solid is recrystallized from diisopropyl ether and dried in vacuum to afford 91.3 g (0.271 mol, yield 90.8 %) of the title compound in form of lightly yellow crystals. m. p.: 220 - 222 °C (diisopropyl ether)
B. (8R/9R)-8-Acetoxy-2/3-dimethyl-9-phenyl-7H-8/9-dihydro-pyrano[2/3-c]imidazo[l/2-a]-pyridin-
7-on
3.18 ml (0.025 mol) of orthoacetic acid trimethyl ester, 0.16 g (0.0006 mol) of pyridinium-p-toluenesulfonate and 0.28 ml (0.007 mol) of formic acid are added at room temperature to a solution of 2 g (0.006 mol) of 2/3-dimethyl-7-[(2R/3S)-2/3-diyhdroxy-3-phenylpropan-l-on-l-yl]imidazo-[l/2-a]-pyridin-8-ol in 40 ml of dichloromethane. After stirring for 16 h at room temperature, the reaction mixture is diluted with dichloromethane, washed with saturated sodium bicarbonate solution, dried over sodium sulphate and the solvent removed under vacuum. The crude product is purified by filtration over a thin layer of silica gel (solvent dichloromethane / methanol: 100 / 1). After removal of the solvent, 1.8 g (0.005 mol, yield 84 %) of the title compound is obtained in form of colourless crystals, m. p.: 205 - 206 °C (diethyl ether / acetone).
C. (8R,9R)-2,3-Dimethyl-8-isobutyryloxy-9-phenyI-7H-8,9-dihydro-pyrano[2,3-c]imidazo-
[l,2-a]pyridin-7-on
1.81 g (0.012 mol) of orthoisobutyric acid trimethyl ester, 0.08 g (0.0003 mol) of pyridinium-p-toluenesulfonate and 0.14 ml (0.004 mol) of formic acid are added at room temperature to a solution of 1 g (0.003 mol) of 2,3-dimethyl-7-[(2R,3S)-2,3~diyhdroxy-3-phenylpropan-l-on-l-yl]imidazo-[l,2-a]-pyridin-8-ol in 10 ml of dichloromethane. After stirring for 16 h at room temperature, the reaction mixture is poured onto a saturated sodium bicarbonate solution, the aqueous layer extracted with dichloromethane, the combined organic layers dried over sodium sulphate and the solvent removed under vacuum. The crude product is purified by chromatography on silica gel (eluent dichloromethane / methanol : 100 / 3) to give 0.98 g (0.003 mol, yield 85 %) of the title compound in form of colourless crystals, m. p.: 207 - 208 °C (acetone).
16

Commercial utility
The compounds of the formula 1 and their salts are valuable intermediates for the preparation of active compounds, such as are disclosed, for example, in the international patent applications WO 98/54188, WO 01/72756, WO 01/72754, WO 01/72755, WO 01/72757, WO 02/34749, WO 03/016310, WO 03/014120 and WO 03/014123.
17


We Claims
1. A compound of the formula 1
in which
Rl is hydrogen, l-4C-alkyl, 3-7C-cycloalkyl, 3-7C-cycloalkyl-l-4C-alkyI, l-4C-alkoxy, 1-4C-
alkoxy- l-4C-alkyl, l-4C-alkoxycarbonyl, 2-4C-alkenyl, 2-4C-alkynyl, fluoro-l-4C-alkyl or
hydroxy-1 -4C-alky 1, R2 is hydrogen, l-4C-alkyl, aryl, 3-7C-cycloalkyl, 3-7C-cycloalkyl-l-4C-alkyl, 1-4C-
alkoxycarbonyl, hydroxy-l-4C-alkyl, halogen, 2-4C-alkenyl, 2-4C-alkynyl, fluoro-l-4C-alkyl,
cyanomethyl, R3a is hydrogen, halogen, fluoro-l-4C-alkyl, l-4C-alkyl, 2-4C-alkenyl, 2-4C-alkynyl, carboxyl, 1-
4C-alkoxycarbonyl, hydroxy-l-4C-alkyl, l-4C-alkoxy-l-4C-alkyl, l-4C-alkoxy-l-4C-alkoxy-l-
4C-alkyl, fluoro-l-4C-alkoxy-l-4C-alkyl or the radical -CO-NR31R32, R3b is hydrogen, halogen, fluoro-l-4C-alkyl, l-4C-alkyl, 2-4C-alkenyl, 2-4C-alkynyl, carboxyl, 1-
4C-alkoxycarbonyl, hydroxy-l-4C-alkyl, l-4C-alkoxy-l-4C-alkyl, l-4C-alkoxy-l-4C-alkoxy-l-
4C-alkyl, fluoro-l-4C-alkoxy-l-4C-alkyl or the radical -CO-NR31R32,
where
R31 is hydrogen, l-7C-alkyl, hydroxy-l-4C-alkyl or l-4C-alkoxy-l-4C-alkyl and
R32 is hydrogen, l-7C-alkyl, hydroxy-l-4C-alkyl or l-4C-alkoxy-l-4C-alkyl,
or where
R31 and R32 together, including the nitrogen atom to which both are bonded, are a pyrrolidine, piperidino, piperazino, N-l-4C-alkylpiperazino or morpholino radical, Arom is a mono- or bicyclic aromatic radical substituted by R4, R5, R6 and R7, which is selected
from the group consisting of phenyl, naphthyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl,
indolyl, benzimidazolyl, furanyl (furyl), benzofuranyl (benzofuryl), thiophenyl (thienyl),
benzothiophenyl (benzothienyl), thiazolyl, isoxazolyl, pyridinyl, pyrimidinyl, quinolinyl and
isoquinolinyl,
where
R4 is hydrogen, l-4C-alkyl, hydroxy-l-4C-alkyl, l-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, l-4C-alkoxycarbonyl, carboxy-l-4C-alkyl, l-4C-alkoxycarbonyl-l-4C-alkyl, halogen, hydroxyl, aryl, aryl-l-4C-alkyl, aryloxy, aryl-l-4C-alkoxy,
18

trifluoromethyl, nitro, amino, mono- or di-l-4C-alkylamino, l-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, l-4C-alkoxy-l-4C-alkoxycarbonylamino or sulfonyl,
R5 is hydrogen, l-4C-alkyl, l-4C-alkoxy, l-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl,
R6 is hydrogen, l-4C-alkyl or halogen and
R7 is hydrogen, l-4C-alkyl or halogen,
where
aryl is phenyl or substituted phenyl having one, two or three identical or different substi-tuents from the group consisting of l-4C-alkyl, l-4C-alkoxy, carboxyl, l-4C-alkoxy-carbonyl, halogen, trifluoromethyl, nitro, trifluoromethoxy, hydroxyl and cyano, and its salts.
2. A compound of the formula 1 according to claim 1, in which
Rl is hydrogen, l-4C-alkyl, 3-7C-cycloalkyl, l-4C-alkoxy-l-4C-alkyl, 2-4C-alkynyI or fluoro-l-4C-
alkyl, R2 is hydrogen, l-4C-alkyl, aryl, hydroxy-l-4C-alkyl, halogen, 2-4C-alkenyl, 2-4C-alkynyl,
fluoro-l-4C-alkyl, R3a is hydrogen, R3b is hydrogen, halogen, l-4C-alkyl or the radical -CO-NR31R32,
where
R31 is hydrogen, l-7C-alkyl, hydroxy-l-4C-alkyl or l-4C-alkoxy-l-4C-alkyl and
R32 is hydrogen, l-7C-alkyl, hydroxy-l-4C-alkyl or l-4C-alkoxy-l-4C-alkyl,
or where
R31 and R32 together, including the nitrogen atom to which both are bonded, are a
pyrrolidine piperidino, piperazino, N-l-4C-alkylpiperazino or morpholino radical, Arom is a monocyclic aromatic radical substituted by R4, R5, R6 and R7, which is selected from the
group consisting of phenyl, furanyl (furyl) and thiophenyl (thienyl),
where
R4 is hydrogen, l-4C-alkyl, hydroxy-l-4C-alkyl, l-4C-alkoxy, l-4C-alkykarbonyl, carboxyl, 1-4C-alkoxycarbonyl, halogen, hydroxyl, trifluoromethyl, l-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, l-4C-alkoxy-l-4C-alkoxycarbonylamino or sulfonyl,
R5 is hydrogen, l-4C-alkyl, l-4C-alkoxy, l-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl,
R6 is hydrogen and
R7 is hydrogen, and its salts.
3. A compound of the formula 1 according to claim 1, in which
19

Rl is l-4C-alkyl or l-4C-alkoxy-l-4C-alkyl,
R2 is hydrogen, l-4C-alkyl, phenyl, hydroxy-l-4C-alkyl, halogen,
R3a is hydrogen,
R3b is hydrogen,
Arom is phenyl, furanyl (furyl) or thiophenyl (thienyl),
and its salts.
4. A compound according to claim 1, characterized by the general formula 1*,

in which
Rl is hydrogen, l-4C-alkyl, 3-7C-cycloalkyl, l-4C-alkoxy-l-4C-alkyl, 2-4C-alkynyl or fluoro-l-4C-
alkyl, R2 is hydrogen, l-4C-alkyl, aryl, hydroxy-l-4C-alkyl, halogen, 2-4C-alkenyl, 2-4C-alkynyl,
fluoro-l-4C-alkyl, R3a is hydrogen, R3b is hydrogen, halogen, l-4C-alkyl or the radical -CO-NR31R32,
where
R31 is hydrogen, l-7C-alkyl, hydroxy-l-4C-alkyl or l-4C-alkoxy-l-4C-alkyl and
R32 is hydrogen, l-7C-alkyl, hydroxy-l-4C-alkyI or l-4C-alkoxy-l-4C-alkyl,
or where R31 and R32 together, including the nitrogen atom to which both are bonded, are a pyrrolidino,
piperidino or morpholino radical Arom is phenyl, furanyl (furyl) or thiophenyl (thienyl), and its salts.
5. A compound according to claim 1, characterized by formula 1* according to claim 4, in which
Rl is hydrogen, methyl, cyclopropyl, methoxymethyl or trifluoromethyl,
R2 is hydrogen, methyl, phenyl, hydroxymethyl, chloro, bromo, ethynyl, trifluoromethyl,
R3a is hydrogen,
R3b is hydrogen, fluorine, methyl or the radical -CO-N(CH3)2,
Arom is a phenyl radical
20

and its salts.
6. A compound according to claim 1, characterized by formula 1* according to claim 4, in which
Rl is methyl,
R2 is hydrogen, methyl, fluoro, chloro, bromo, hydroxymethyl or trifluoromethyl, R3a is hydrogen, R3b is hydrogen, Arom is a phenyl radical and its salts.
7. The use of compounds of the formula 1 as claimed in claim 1, in which Rl, R2, R3a, R3b and
Arom have the meanings indicated in claim 1, for the preparation of compounds of the formula 2 or
their salts

in which Rl, R2, R3a, R3b and Arom have the meanings indicated in claim 1, and R8 is hydrogen, 1-4C-Alkyl or aryl, where aryl has the meaning as indicated in claim 1.
8. The use of compounds of the formula 1* as claimed in claim 4, in which Rl, R2, R3a, R3b and Arom have the meanings indicated in claim 4, for the preparation of compounds of the formula 2*


or their salts







in which Rl, R2, R3a, R3b and Arom have the meanings indicated in claim 4, and R8 is hydrogen, 1-4C-Alkyl or aryl, where aryl has the meaning as indicated in claim 1.
21

9. Process for the preparation of the compounds of the formula 1 as claimed in claim 1, in which Rl, R2, R3a, R3b and Arom have the meanings indicated in claim 1, which comprises deprotection of a compound of the formula 3,

in which Rl, R2, R3a, R3b and Arom have the meanings indicated in claim 1, by use of a mineral acid and then working up.
10. Process for the preparation of the compounds of the formula 1* as claimed in claim 4, in which Rl, R2, R3a, R3b and Arom have the meanings indicated in claim 4, which comprises deprotection of a compound of the formula 3*,

in which Rl, R2, R3a, R3b and Arom have the meanings indicated in claim 4, by use of a mineral acid and then working up.
Dated this 16 th day of .December , 2005

22

Abstract
The invention relates to compounds of the formula 1,

in which the substituents and symbols have the meanings indicated in the description. The compounds are valuable intermediates for the preparation of pharmaceutical active compounds.
To
The Controller of Patent
The Patent Office
Mumbai
23

Documents:

1336-mumnp-2005-abstract(1-12-2005).pdf

1336-mumnp-2005-abstract(granted)-(25-2-2009).pdf

1336-mumnp-2005-abstract.doc

1336-mumnp-2005-cancelled pages(25-7-2007).pdf

1336-mumnp-2005-claims(amended)-(25-7-2007).pdf

1336-mumnp-2005-claims(granted)-(25-2-2009).pdf

1336-mumnp-2005-claims.doc

1336-mumnp-2005-claims.pdf

1336-mumnp-2005-correspondence(25-7-2007).pdf

1336-mumnp-2005-correspondence(ipo)-(24-3-2009).pdf

1336-mumnp-2005-correspondence-others.pdf

1336-mumnp-2005-description (complete).pdf

1336-mumnp-2005-description(granted)-(25-2-2009).pdf

1336-mumnp-2005-form 1(1-12-2005).pdf

1336-mumnp-2005-form 2(granted)-(25-2-2009).pdf

1336-mumnp-2005-form 2(title page)-(complete)-(1-12-2005).pdf

1336-mumnp-2005-form 2(title page)-(granted)-(25-2-2009).pdf

1336-MUMNP-2005-FORM 3(25-7-2007).pdf

1336-mumnp-2005-form-1.pdf

1336-mumnp-2005-form-18.pdf

1336-mumnp-2005-form-2.doc

1336-mumnp-2005-form-2.pdf

1336-mumnp-2005-form-3.pdf

1336-mumnp-2005-form-5.pdf

1336-MUMNP-2005-GENERAL POWER OF ATTORNEY(1-12-2005).pdf

1336-mumnp-2005-wo international publication report(1-12-2005).pdf


Patent Number 230107
Indian Patent Application Number 1336/MUMNP/2005
PG Journal Number 13/2009
Publication Date 27-Mar-2009
Grant Date 25-Feb-2009
Date of Filing 01-Dec-2005
Name of Patentee ALTANA PHARMA AG
Applicant Address Byk-Gulden-Str. 2, 78467 Konstanz (DE)
Inventors:
# Inventor's Name Inventor's Address
1 BREHM, Christof Richentalstr. 8, 78462 Konstanz (DE)
2 BUHR, Wilm Zum Kirchenwald 7, 78465 Konstanz (DE)
3 ZIMMERMANN, Peter, Jan Zum Lerchental 43/1, 78315 Radolfzell (DE).
4 CHIESA, Vittoria, M Alpenstr. 5, 78464 Konstanz (DE).
5 PALMER, Andreas Pirminweg 1a, 78467 Konstanz (DE).
PCT International Classification Number C07D47/04
PCT International Application Number PCT/EP2004/050693
PCT International Filing date 2004-05-04
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 03010218.0 2004-05-06 EUROPEAN UNION