| 摘要 |
<p>beta -Lactam compounds of the formula (Ia) including pharmaceutically acceptable salts and in vivo hydrolysable esters, processes for their preparation and their use as antibiotics: <CHEM> wherein R<1> is hydrogen, methoxy or formamido; R<2> is an acyl group, in particular that of an antibacterially active cephalosporin; CO2R<6> is a carboxy group or a carboxylate anion; R<3> is a gamma -lactone ring optionally containing an endocyclic double bond, which ring is optionally substituted at any carbon atom by alkyl, dialkylamino, alkoxy, hydroxy, halogen or aryl, which in the case of more than one substituent may be the same or different, or is optionally di-substituted at two adjacent carbon atoms, which are available for substitution, to form an aromatic fused bicyclic system; and X is S, SO, SO2, O or CH2.</p> |
