摘要:
Mercapto amino acid derivatives of formula (I), wherein R is hydrogen, a salt-forming cation of a in vivo hydrolysable ester-forming group; R.sub.1 is selected from (a) and (b) in which A is a monocyclic aryl or heteroaryl ring and B is a monocyclic aryl, alicyclic or heterocyclic ring, C and D are independently --Z.sub.p --(CR.sub.8 CR.sub.9).sub.q -- or --(CR.sub.8 CR.sub.9).sub.q --Z.sub.p -- where p is 0 or 1, q is 0 to 3 provided that p+q in C is not 0, R.sub.8 and R.sub.9 are independently hydrogen or (C.sub.1-6)alkyl or together represent oxo and Z is O, NR.sub.10 or S(O).sub.x where R.sub.10 is hydrogen, (C.sub.1-6)alkyl or aryl(C.sub.1-6)alkyl and x is 0-2, and wherein C and D are linked ortho to one another on each of the rings A and B in formula (b); R.sub.2 is hydrogen, (C.sub.1-6)alkyl or aryl(C.sub.1-6)alkyl; R.sub.3 is hydrogen, (C.sub.1-6)alkyl optionally substituted by up to three halogen atoms, (C.sub.3-7)cycloalkyl, fused aryl(C.sub.3-7)cycloalkyl, (C.sub.3-7)cycloalkyl(C.sub.2-6)alkyl, (C.sub.2-6)alkenyl, (C.sub.2-6)alkynyl, aryl, aryl--(CH.sub.2).sub.m --X--(CH.sub.2).sub.n, heterocyclyl or heterocyclyl--(CH.sub.2).sub.m --X--(CH.sub.2).sub.n, where m is 0 to 3, n is 1 to 3 and X is O or S(O).sub.x where x is 0-2 or a bond; R.sub.4 is hydrogen or an in vivo hydrolysable acyl group; and R.sub.5 and R.sub.6 are independently hydrogen and (C.sub.1-6)alkyl or together represent (CH.sub.2).sub.r, where r is 2 to 5; for use in treatment of bacterial infections in humans or animals by administration in combination with a .beta.-lactam antiobiotic.