| 摘要 |
Cephems and analogues of formula (I) are new. R = aryl or heterocyclyl; R1 = H or halogen; R2 = single bond, alkylene, oxa-alkylene or thia-alkylene- R3, R6 = H, salt-forming atom or gp. or ester-forming gp.; R4 = H or MeO; R5 = H or a 3-substituent as found in cephalosporins; X = O, S or SO. Provided that when R2 = thia-alkylene, then R1 = halogen. - Intermediates of formula (II) are new. |
