| 摘要 |
The compounds of the formula (I): <IMAGE> (I) wherein R1 is a hydrogen atom, a trityl group or an acyl group as found in known antibacterially active penicillins or cephalosporins; R2 is a hydrogen atom, a lower alkyl group or an aryl group; R3 is a hydrogen atom, a lower alkyl group, a substituted lower alkyl or a thiosubstituted lower alkyl group; and R4 is a group such that CO2R4 is a carboxylic acid group or a salt or readily removable ester thereof; are antibiotics. The compounds may be formulated in pharmaceutical compositions. Processes for the preparation of the compounds (I) are also described. |
