Compounds of the formula ##STR1## in which R.sub.1 is lower alkyl substituted by hydroxy or by protected hydroxy, R.sub.2 represents carboxy or functionally modified carboxy, and R.sub.3 represents amino, lower alkyl-substituted amino, substituted methyleneamino or protected amino, optical isomers of compounds of the formula I, mixtures of these optical isomers, and salts of such compounds of the formula I that have a salt-forming group have antibiotic activity. The compounds of the formula I are manufactured according to processes that are known per se.
公式为##STR1##的化合物,其中R.sub.1是被羟基或受保护的羟基取代的低碳基,R.sub.2代表羧基或功能修饰的羧基,R.sub.3代表
氨基,低碳基取代的
氨基,取代的亚甲基
氨基或受保护的
氨基,公式I的光学异构体,这些光学异构体的混合物以及具有成盐基团的公式I的这种化合物的盐具有抗生素活性。公式I的化合物是按照已知的方法制造的。