Patent ID: 7101882

Claim:
A compound of formula (I): wherein: R 1 is C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 2-6 alkynyl-Y 1 —, aryl-Y 1 —, C 2-6 alkenyl-Y 1 —, aryl-O—Y 1 —, aryl-(O),-aryl-Y 1 , C 1-6 alkyl-SO 2 —Y 1 —, M—Y 1 —, —CN or C 3-8 cycloalkyl-Y 1 — or C 3-8 cycloalkenyl-Y 1 —, wherein cycloalkyl or cycloalkenyl may be optionally substituted by one or more hydroxyl or C 1-6 alkyl groups; R 2 is hydrogen or C 1-6 alkyl; X is ethylene or a group of formula CR e R f wherein R e and R f independently represent hydrogen or C 1-4 alkyl or R e and R f may together with the carbon atom to which they are attached form a C 3-8 cycloalkyl group; R 3 and R 4 are each independently hydrogen or C 1-4 alkyl; Z is a bond, CO, CHR 6 (CH 2 ) n , CHR 6 (CH 2 ) n O or CHR 6 (CH 2 ) n CO; R 5 is phenyl which may be optionally substituted by one or more halogen groups or thiophenyl which may be optionally substituted by one or more halogen groups; R 6 is hydrogen, C 1-4 alkyl, CONR 7 R 8 or COOC 1-6 alkyl; a and b are both 1; n is an integer from 0 to 4; R 7 and R 8 are each independently hydrogen or C 1-6 alkyl; M is a C 3-8 cycloalkyl or a C 3-8 cycloalkenyl group fused to a monocyclic aryl; t is 0 or 1; Y 1 is methylene, ethylene, or cyclopropyl; or a physiologically acceptable salt or solvate thereof.