Penem-3-carboxylic acid derivatives of formula (I): ##STR1## (wherein: R.sup.1 represents a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyalkyl group, an acyloxyalkyl group, an alkylsulphonyloxyalkyl group, an arylsulphonyloxyalkyl group or a trialkylsilyloxyalkyl group; R.sup.2 represents a hydrogen atom or an alkyl group; R.sup.3 represents a hydrogen atom, an amino-protecting group or a group of formula ##STR2## in which R.sup.5 and R.sup.6 are the same or different and each represents a hydrogen atom or an alkyl group; A represents a branched-chain alkylene group; and R.sup.4 represents a carboxy group or a protected carboxy group) and pharmaceutically acceptable salts thereof, may be prepared by heating a corresponding phosphorus-ylide compound or by reacting a corresponding azetidin-2-one with a suitable phosphorous acid triester or triamide, and have been found to have excellent antibacterial activity accompanied by a very low acute toxicity.
公式(I)的Penem-3-
羧酸衍
生物:##STR1##(其中:R.sup.1代表氢原子,烷基,烷氧基,羟基烷基,酰氧烷基,烷基磺酰氧烷基,芳基磺酰氧烷基或三烷基
硅氧烷基;R.sup.2代表氢原子或烷基;R.sup.3代表氢原子,
氨基保护基或式子##STR2##中R.sup.5和R.sup.6相同或不同,每个代表氢原子或烷基;A代表支链烷基;R.sup.4代表羧基或保护羧基),以及其药学上可接受的盐,可以通过加热相应的膦-叶立德化合物或通过将相应的氮杂
环己烷-2-酮与适当的
磷酸三酯或三酰胺反应制备,发现具有出色的抗菌活性,并伴随着非常低的急性毒性。