Compounds of formula (I) are inhibitors of matrix metalloproteinases, and are of use in the treatment of, for example fibrotic disease, multiple sclerosis, emphysemia, bronchitis and asthma: formula (I) wherein Ar represents an optionally substituted aryl, heteroaryl, C3-C8 cycloalkyl or heterocycloakyl group; R represents hydrogen or C1-C6 alkyl, or C3-C6 cycloalkyl; Alk represents a divalent C1-C5 alkylene or C2-C5 alkenylene radical; and R1 and R2 taken together with the nitrogen atom to which they are attached form a first heterocycloalkyl ring which is optionally fused to a second C3-C8 cycloalkyl or heterocycloalkyl ring, the said first and second rings being optionally substituted by at least one group of formula (II): formula (II) wherein m, p and n are independently 0 or 1; Z represents, hydrogen, or an optionally substituted carbocyclic or heterocyclic ring of from 5 to 7 ring atoms which is optionally fused to another optionally substituted carbocyclic or heterocyclic ring of from 5 to 7 ring atoms; Alk<1> and Alk<2> independently represent optionally substituted divalent C1-C3 alkylene radicals; X represents -0-, -S-, -S(O)-, -S(O2)-, -C(=O)-, -NH-, -NR3-, -S(O2)NH-, -S(O2)NR3-, -NHS(O2)-, or -NR3S(O2)-, where R3 is C1-C3 alkyl. |