A compound of formula (I) in which R¹ is halo, lower alkoxy, optionally substituted aryl, optionally substituted aryloxy, optionally substituted heterecyclic group or optionally substituted lower alkynyl, R² is amidated carboxy, R³ is hydrogen or acyl, Ar is aryl or heterocyclic group, X is thia, sulfinyl or sulfonyl, Y and Z are each lower alkylene, m and n are each an integer of 0 to 2, and a salt thereof, useful as inhibitors of matrix metalloproteinases (MMP) or the production of tumor necrosis factor (TNF ) ##STR1##