| 摘要 |
A cephalosporin of the formula (I): <IMAGE> (I) wherein A is a mono- or polycyclic heteroaromatic ring containing at least one nitrogen atom as a hetero atom, which may be unsubstituted or substituted; R is a phenyl group which may be unsubstituted or substituted, a thienyl group, a furyl group, a cyclohexadienyl group or a cyclohexenyl group; X is an acetoxy group, a pyridinium group which may be unsubstituted or substituted with a methyl or carbamoyl group, a group of the formula: <IMAGE> in which R1 and R2, which may be the same or different, each is a hydrogen atom or a (C1 - C4) alkyl group, or a group of the formula: |
