The compounds of the general formula I 
wherein R1 denotes hydrogen, hydroxymethyl or 1-hydroxyethyl, R2 denotes hydrogen or methyl and R3 denotes a pharmaceutically acceptable group which is bonded to the remaining part of the molecule by an oxygen-carbon single bond or a nitrogen-carbon single bond, and their pharmaceutically acceptable salts, esters and amide derivatives are broad spectrum antibiotics and &bgr;-lactamase inhibitors.
                            通式I的化合物,其中R1表示氢,羟甲基或1-羟乙基,R2表示氢或甲基,R3表示与分子的其余部分通过氧-碳单键或氮-碳单键结合的药用可接受基团,以及它们的药用可接受盐,酯和酰胺衍
生物是广谱抗生素和&bgr;-内酰胺酶
抑制剂。