Pharmaceutical Compounds

A compound of formula I:

• wherein R1 and R2 are independently from each other hydrogen or a group which is hydrolysable under physiological conditions, optionally substituted lower alkanoyl or aroyl;
• X represents a methylene group;
• Y represents an atom of oxygen, nitrogen or sulphur;
• n represents the number 0, 1, 2 or 3 and m represents the number 0 or 1;
• R3 represents a pyridine group according to the formula A, B or C, which is connected as indicated by the unmarked bond:
• where R4, R5, R6 and R7 independently from each other represent hydrogen, C1-C6-alkyl, C1-C6-thioalkyl, C1-C6-alkoxy, C6-C12-aryloxy or a C6-C12-thioaryl group, C1-C6-alkanoyl or C7-C13-aroyl group, amino, C1-C6— alkylamino, C1-C6-dialkylamino, C3-C12-cycloalkylamino, C3-C12-heterocycloalkylamino, C1-C6-alkylsulphonyl, C6-C12-arylsulphonyl, halogen, C1-C6-haloalkyl, trifluoromethyl, cyano, nitro or a heteroaryl group;
• or two or more of residues R4, R5, R6 and R7 taken together represent aliphatic or heteroaliphatic rings or aromatic or hetero aromatic rings and wherein P represents a central unit, which is preferably a planar unit and which is even more preferably selected from the regioisomers of 1,3,4-oxadiazol-2,5-diyl, 1,2,4-oxadiazol-3,5-diyl, 4-methyl-4H-1,2,4-triazol-3,5-diyl, 1,3,5-triazin-2,4-diyl, 1,2,4-triazin-3,5-diyl, 2H-tetrazol-2,5-diyl, 1,2,3-thiadiazol-4,5-diyl, 1-alkyl-3-(alkoxycarbonyl)-1H-pyrrol-2,5-diyl, wherein alkyl is represented by methyl, ethyl, n-propyl and n-butyl and wherein alkoxy is represented by methoxy, ethoxy, n-propoxy and isopropoxy, 1-alkyl-1H-pyrrol-2,5-diyl, wherein alkyl is represented by methyl, ethyl, n-propyl and n-butyl, thiazol-2,4-diyl, 1-H-pyrazol-1,5-diyl, pyrimidin-2,4-diyl, oxazol-2,4-diyl, carbonyl, 1H-imidazol-1,5-diyl, isoxazol-3,5-diyl, furan-2,4-diyl, 3-alkoxycarbonylfuran-2,4-diyl, wherein alkoxy is represented by methoxy, ethoxy, n-propoxy and isopropoxy, benzene-1,3-diyl and (Z)-1-cyanoethen-1,2-diyl;
• or a pharmaceutically acceptable salt or ester of a compound of formula I.