| 摘要 |
<p><IMAGE> Penams IV (N=0, 1 or 2, R=H or a carboxy protecting group, R1=H, alkyl, alkoxy, cycloalkyl or optionally protected hydroxyalkyl, especially 1-hydroxyethyl, R3 and Y are certain defined organic groups or R3=H) have antibacterial activity. They may be prepared by cyclising an azetidinone II <IMAGE> (E is a leaving group) and are further useful in the preparation of known antibacterial penems I <IMAGE></p> |
