| 摘要 |
Compounds of the formula (II): <IMAGE> (II) wherein A is a group such that CO2A is carboxylic acid, a non-toxic salt thereof or non-toxic ester thereof; R1 is COR4 or OR5 wherein R4 is lower alkyl, lower alkenyl, lower alkyl aryl or aryl and R5 is CO2R6, COR6 or SO2R6 wherein R6 is lower alkyl, lower alkenyl, lower alkyl aryl or aryl; and R2 is COR8 wherein R8 is lower alkyl, lower alkenyl, lower alkyl aryl or aryl; when R1 is COR4 and R2 is COR8, R4 and R8 are joined so that the N(COR4) COR8 moiety is a 5-,6-, or 7-membered heterocyclic ring or said ring to which is fused a phenyl ring unsubstituted or substituted by one or two lower alkyl, lower alkoxyl, fluorine or chlorine; when R1 is OR5 and R2 is COR8, R5 and R8 are joined so that the N(OR5) COR8 moiety is a 5-, 6-, or 7-membered heterocyclic ring, are useful for their antibacterial activity and as synergists for penicillins and cephalosporins. |
