Synthesis and beta-lactamase inhibitory activity of new 6 beta-cysteinesulfonamidopenicillanic acids

New 6 beta-cysteinesulfonamidopenicillanic acids and their sulfoxides were synthesized by sulfonylation of 6 beta-aminopenicillanic acid or its (S)-su lfoxide with (R)-N-benzyloxycarbonylcysteinesulfonyl chloride ethyl ester ( 2a, 1b) and (R)-N-benzyloxycarbonylcysteinesulfonyl chloride benzyl eater ( 2a, 2b). The corresponding 6 beta-cysteinesulfonamidopenicillanic acids sul fones 1c and 2c were prepared by oxidation of the sulfoxides 1b and 2b with potassium permanganate in aqueous medium. When combined with ampicillin so me of the compounds reduced the minimal inhibitory concentrations of ampici llin against beta-lactamase producing strains. (C) 1999 Elsevier Science Lt d. All rights reserved.