The present invention is based on the discovery that certain 3-(substituted methyl)-4-oxa-1-azabicyclo[3.2.0]heptan-7-one derivatives of formula I or a pharmaceutically acceptable salt thereof are useful as antitumor agents against sensitive and resistant tumor cells. ##STR1## Wherein X is NH or O, and R is defined in the specification.
本发明基于发现,公式I中的某些3-(取代甲基)-4-氧-1-
氮杂双环[3.2.0]
庚烷-7-酮衍
生物或其药学上可接受的盐可用作对敏感和耐药肿瘤细胞的抗肿瘤剂。其中X为NH或O,R在说明书中有定义。