Disclosed are compounds which have not only potent metalloproteinase-inhibiting activity but also amazingly excellent bioavailability and biological activity in vivo, including the property of being well absorbed via oral routes, thereby serving as useful pharmaceuticals, intermediates and processes for the production thereof. The disclosed compounds of the formula (I):
wherein R 1 is hydrogen, or a hydroxy-protecting group; R 2 is hydrogen, or an amino-protecting group; R 3 , R 7 , and R 8 , which may be identical or different, are each independently hydrogen, hydroxy, unsubstituted or optionally substituted (C 1 -C 6 ) alkyl, or unsubstituted or optionally substituted aryl-(C 1 -C 6 ) alkyl; R 4 is unsubstituted or optionally substituted (C 1 -C 6 ) alkyl, or unsubstituted or optionally substituted aryl-(C 1 -C 6 ) alkyl; R 5 is hydrogen, unsubstituted or optionally substituted alkyl, unsubstituted or optionally substituted aralkyl, or a carboxy-protecting group; R 6 is hydrogen, hydroxy, amino, and a group of the formula: -X-Y wherein X is oxygen, (C 1 -C 6 ) alkylene or phenylene, Y is a group of the formula: -A-B or -B, wherein A is (C 1 -C 6 ) alkylene, imino, and (C 1 -C 6 ) alkyleneimino, and B is hydrogen, amino, amidino, sulfonyl, acylimidoyl, unsubstituted or optionally substituted imidazolyl, unprotected or optionally protected bis(phosphono)methyl or unprotected or optionally protected bis(phosphono)hydroxymethyl; or salts thereof are useful for pharmaceutical and/or veterinary compositions, particularly as metalloproteinase inhibitors which inhibit matrix metalloproteinases or tumor necrosis factor-α-converting enzymes (TNF-α convertases).