Studies on beta-lactam antibiotics. III. Synthesis and enzymatic stability of 3-acyloxymethyl-7 beta-[(Z)-2-(2-amino-4-thiazolyl)-2-(methoxyimino)acetamido]-3-cephem-4-carboxylic acids

3-Acyloxymethyl-7 beta-[(Z)-2-(2-amino-4-thiazolyl)-2-(methoxyimino) acetamido]-3-cephem-4-carboxylic acids (7) were synthesized. The stability of 7 to enzymatic hydrolysis and their antimicrobial activity were evaluated. 7 showed good antimicrobial activity against a wide range of Microorganisms. Cephems (7b and 7c) with sterically more hindered acyl groups such as t-butyl and cyclohexyl were most resistant to enzymatic hydrolysis.