7{60 {0 Ureido cephem-4-carboxylic acid derivatives

摘要

6-Acylamino-penam-3-carboxylic acids and 7-acylamino-3-cephem-4-carboxylic acids in which the acyl group has the formula <IMAGE> in which R1 is hydrogen, R2 is optionally substituted phenyl, thienyl or furyl, or R1 and R2 together are optionally substituted cycloalkyl, and B is a radical which is bonded via a sulphur atom or is bonded to oxygen or sulphur with the interposition of an optionally substituted CH2-group.