.beta.-Lactam compounds of the formula (I) including pharmaceutically acceptable salts and in vivo hydrolysable esters, processes for their preparation and their use as antibiotics: ##STR1## wherein R.sup.1 is hydrogen, methoxy or formamido; R.sup.2 is an acyl group, in particular that of an antibacterially active cephalosporin; R.sup.3 is hydrogen or a readily removable carboxy protecting group (such as a pharmaceutically acceptable in-vivo hydrolysable ester group); R.sup.4 is a .gamma.- or .delta.-lactone ring optionally containing one or (where applicable) two endocyclic double bonds, which ring is optionally substituted at any carbon atom by alkyl, dialkylamino, alkoxy, hydroxy, halogen or aryl, which in the case of more than one substituent may be the same or different, or is optionally di-substituted at two adjacent carbon atoms, which are available for substitution, to form an aromatic fused bicyclic system; x and y are independently 0 or 1; X is S, SO, SO.sub.2, O or CH.sub.2 ; and Y is O or S.
.beta.-内酰胺化合物的
化学式(I),包括药学上可接受的盐和体内
水解酯,其制备过程和用作抗生素的方法:##STR1## 其中R.sup.1是氢,甲氧基或甲酰胺基; R.sup.2是酰基,特别是抗菌活性
头孢菌素的酰基; R.sup.3是氢或易于去除的羧基保护基(例如药学上可接受的体内
水解酯基); R.sup.4是含有一个或(适用时)两个内环双键的γ-或δ-内酯环,该环在任何碳原子上均可选择性地取代为烷基,双烷基
氨基,烷氧基,羟基,卤素或芳基,在存在多个取代基的情况下,可能相同或不同,或者在两个相邻的可取代碳原子处选择性地双取代,以形成芳香融合的双环系统; x和y独立地为0或1; X为S,SO,SO.sub.2,O或CH.sub.2; Y为O或S。