Compounds of the formula I ##STR1## wherein R' is a free or esterified carboxy group or a carboxylate anion and R.sup.2 is an organic group have beta-lactamase inhibition activity. A process for the preparation of the same and pharmaceutical compositions containing these compounds are provided.
式I的化合物
其中R'是自由或酯化的羧基或
羧酸盐根,R.sup.2是有机基团,具有β-内酰胺酶抑制活性。提供了制备这些化合物的方法和含有这些化合物的药物组合物。