Disclosed are substituted azetidinones (1) which are useful in the preparation of 1-carba-2-penem-3-carboxylic acids (I): ##STR1## wherein R is hydrogen or a blocking group and R.sup.1, R.sup.2 and R.sup.3 are, inter alia, independently selected from the group consisting of hydrogen, alkyl, aryl, and aralkyl. Such 1-carba-2-penem-3-carboxylic acids and their pharmaceutically acceptable salt, ester and amide derivatives are useful as antibiotics.
本发明涉及一种替代的氮杂四元酮(1),其在1-卡巴-2-青霉烷-3-
羧酸(I)的制备中有用:##STR1## 其中R是氢或阻断基,R.sup.1,R.sup.2和R.sup.3是独立地选自氢,烷基,芳基和芳基烷基等组的。这种1-卡巴-2-青霉烷-3-
羧酸及其药学上可接受的盐,酯和酰胺衍
生物作为抗生素有用。