| 摘要 |
<p>Penem-3-carboxylic acid derivatives of formula (I): <IMAGE> (I) (wherein: R1 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; R2 represents a hydrogen atom or an alkyl group; R3 represents a hydrogen atom, an amino-protecting group or a group of formula <IMAGE> in which R5 and R6 are the same or different and each represents a hydrogen atom or an alkyl group; A represents a branched-chain alkylene group; and R4 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.</p> |
