Carboxylic acid derivatives, their preparation and use

1. A pharmaceutical composition comprising a compound of formula I:

or a pharmaceutically acceptable salt thereof,

where R is a COOH group or a radical which can be hydrolyzed to COOH;

R 2 is a C 1 -C 4 -alkyl or C 1 -C 4 -alkoxy;

X is CR 14 where R 14 is hydrogen or C 1 -C 5 -alkyl, or CR 14 forms together with CR 3 a 5- or 6-membered alkylene or alkenylene ring which can be substituted by one or two C 1 -C 4 -alkyl groups and in which in each case a methylene group can be replaced by an oxygen;

R 3 is a C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy or CR 3 is linked to CR 14 as indicated above to give a 5- or 6-membered ring;

R 4 and R 5 are each independently

phenyl or naphthyl, a methylene, ethylene or ethenylene group, an oxygen or sulfur atom or an SO 2 , NH or N-alkyl group or a C 3 -C 7 -cycloalkyl;

R 6 is a hydrogen, C 1 -C 8 alkyl, or C 3 -C 8 -cycloalkyl, where each of these radicals can be substituted with one or more substituents selected from the group consisting of: halogen, nitro, cyano, C 1 -C 4 -alkoxy, C 3 -C 6 -alkenyloxy, C 3 -C 6 -alkynyloxy, C 1 -C 4 -alkylthio, C 1 -C 4 -haloalkoxy, C 1 -C 4 -alkylcarbonyl, C 1 -C 4 -alkoxycarbonyl, C 1 -C 8 -alkylcarbonylalkyl, C 1 -C 4 -alkylamino, di-C 1 -C 4 -alkylamino, unsubstituted phenyl, and phenyl or phenoxy, wherein phenyl or phenoxy is substituted by one or more substituents selected from the group consisting of: halogen, nitro, cyano, C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, C 1 -C 4 -alkoxy, C 1 -C 4 -haloalkoxy and C 1 -C 4 -alkylthio;

or R 6 is phenyl or naphthyl, each of which can be substituted by one or more radicals selected from the group consisting of: halogen, nitro, cyano, hydroxyl, amino, C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, C 1 -C 4 -alkoxy, C 1 -C 4 -haloalkoxy, phenoxy, C 1 -C 4 -alkylthio, C 1 -C 4 -alkylamino, C 1 -C 4 -dialkylamino, dioxomethylene and dioxoethylene;

Y is oxygen; and

Z is oxygen;

and a pharmaceutically acceptable carrier.