Cephem derivatives of the general formula ##STR1## in which the R.sub.2 O group is in the syn-position, a process for their manufacture and pharmaceutical formulations which are active against bacterial infections and contain these compounds.
Cephem衍
生物的一般
化学式为##STR1##,其中R.sub.2 O基团处于同构式位置,制备它们的方法以及含有这些化合物并对抗细菌感染具有活性的制药配方。