6-acylamino-penam-3-carboxylic acids and 7-acylamino-3-cephem-4-carboxylic acids in which the acyl group has the formula ##STR1## in which R.sub.1 is hydrogen, R.sub.2 is optionally substituted phenyl, thienyl or furyl or R.sub.1 and R.sub.2 together are optionally substituted cycloalkyl, and R is a radical which is linked through a carbon, oxygen, sulphur or nitrogen atom.
6-酰基
氨基青霉烷-3-
羧酸和7-酰基
氨基-3-
头孢菌素-4-
羧酸,其中酰基的式子为##STR1##,其中R.sub.1为氢,R.sub.2为可选取代苯基、
噻吩基或
呋喃基,或R.sub.1和R.sub.2一起为可选取代的环烷基,而R是通过碳、氧、
硫或氮原子连接的基团。