| abstract |
6 beta -Hydroxymethyl-penicillanic acid sulfone and substituted a derivatives thereof, and their esters, of the formula: <IMAGE> in which R1 is hydrogen or an ester- forming residue readily hydrolysable in vivo; R3 is hydrogen, sulpho, alkoxycarbonyl, alkanoyl, optionally substituted benzoyl; and R4 is hydrogen, alkyl, phenyl, pyridyl, benzyl or beta -phenethyl; are claimed as novel enhancers of the effectiveness of beta - lactam antibiotics against many beta - lactamase producing bacteria. The corresponding benzyl esters are also claimed as novel intermediates therefor. |