A compound of formula (I) or a salt thereof: ##STR1## wherein R.sup.1 is an amino group, an azido group, or an acylamino group as found in antibacterially active penicillins or cephalosporins; R.sup.2 is a hydrogen atom or a C.sub.1-4 alkyl group; R.sup.3 is a hydrogen atom, or a C.sub.1-4 alkyl group optionally substituted by a carboxyl, carboxylic ester, hydroxy, C.sub.1-4 alkyloxy, acyloxy or heterocyclylthio group; and R.sup.4 is hydrogen or a readily removable carboxyl protecting group. The compounds wherein R.sup.1 is an acylamino group are found in known antibacterially active penicillins and cephalosporins and wherein R.sup.4 is a hydrogen, a pharmaceutically acceptable salting ion or an in vivo hydrolyzable ester forming radical may be formulated in pharmaceutical compositions. Processes for the preparation of the compound (I) are also described.
                            式(I)的化合物或其盐:##STR1##其中,R1是
氨基、偶氮基或在抗菌活性
青霉素或
头孢菌素中发现的酰胺基;R2是氢原子或C1-4烷基;R3是氢原子或C1-4烷基,可选地被羧基、
羧酸酯、羟基、C1-4烷氧基、酰氧基或杂环
硫基置换;R4是氢或易于去除的羧基保护基。其中,R1是酰胺基的化合物在已知的抗菌活性
青霉素和
头孢菌素中发现,且其中R4是氢、药学上可接受的盐离子或体内
水解酯形成基团,可以制成药物组合物。还描述了制备化合物(I)的方法。