COMPOUNDS

Compounds of general formula I: (I) wherein: R1 represents a C1-C6 alkyl, phenyl, thiophenyl, substituted phenyl, phenyl(C1-C6)alkyl, heterocyclyl, (C1-C6)alkylcarbonyl phenacyl or substituted phenacyl group; or, when n=O, R1 represents SRx, wherein Rx represents a group: R2 represents a hydrogen atom or a C1-C6 alkyl, C1-C6 alkenyl, phenyl(C1-C6)alkyl, cycloalkyl(C1-C6)alkyl or cycloalkenyl(C1-C6)alkyl group; R3 represents an amino acid residue with R or S stereochemistry or a C1-C6 alkyl, benzyl, (C1-C6 alkoxy)benzyl or benzyloxy(C1-C6 alkyl) group; R4 represents a hydrogen atom or a C1-C6 alkyl group; R5 represents a hydrogen atom or a methyl group; n is an integer having the value 0, 1 or 2; and A represents a C1-C6 hydrocarbon chain, optionaly substituted with one or more C1-C6 alkyl, phenyl or substituted phenyl groups; and their salts and N-oxides are collagenase inhibitors are and useful in the management of disease involving tissue degradation and/or the promotion of wound healing. Diseases involving tissue degradation include arthropathy (particularly rheumatoid arthritis), inflammation, dermatological diseases, bone resorption diseases and tumor invasion.