Crystalline acid addition salts of diastereomerically pure 1-(2,2-dimethylpropionyloxy)ethyl 3-cephem-4-carboxylate The invention relates to crystalline acid addition salt of the two diastereomers of the 1-(2,2-dimethylpropionyloxy)ethyl 3-cephem-4-carboxylate of the general formula II ##STR1## in which X is the anion of a physiologically acceptable, mono- or polybasic, inorganic or organic acid and the group =N--OH is in the syn-position, pharmaceutical formulations which are active against bacterial infections and contain such cephem derivatives, processes for the preparation of the cephem derivatives and the use of the cephem derivatives for combating bacterial infections.
对映异构体纯度高的1-(2,2-二甲基丙酰氧基)乙基3-头孢烯-4-
羧酸的晶态酸加成盐。本发明涉及一般式II中的两个对映异构体的晶态酸加成盐:##STR1## 其中X是生理上可接受的单元或多元无机或有机酸的阴离子,且基团=N-OH处于同构位。含有这种头孢烯衍
生物的活性抗细菌感染的制剂,制备头孢烯衍
生物的工艺以及利用头孢烯衍
生物对抗细菌感染的用途。