Compounds represented by general formula (l),
R represents a hydrogen atom, a carboxyl protective group or an anionic charge, Q represents a hydrogen atom, a halogen atom, a hydroxy group, an acetoxy group, a carbamoyloxy group, an azido group, an optionally substituted quaternary ammonio group, or an optionally substituted 5- or 6- membered aromatic heterocyclic thio group containing at least one hetero atom selected from the group consisting of a nitrogen or a hetero cycling ring)], nontoxic salts thereof or nontoxic esters thereof capable of being physiologically hydrolized, process for their preparation, and antibacterial agent containing the compound as an effective ingredient. Further, compounds represented by general formula (lll), (wherein R3 represents a hydrogen atom or an amino protective group, and R4 and R5, which may be the same or different, each represents a hydrogen atom or a carboxyl protective group) or their salts and process for their preparation.
                            通式(l)代表的化合物、
R 代表氢原子、羧基保护基团或阴离子电荷,Q 代表氢原子、卤素原子、羟基、乙酰氧基、
氨基甲酰氧基、
叠氮基、任选取代的季
铵盐基团、或含有至少一个选自氮或杂环组成的组中的杂原子的任选取代的 5 或 6 位芳香杂环
硫基]、其无毒盐或可生理
水解的无毒酯、其制备方法以及含有该化合物作为有效成分的抗菌剂。此外,通式(lll)代表的化合物(其中 R3 代表氢原子或
氨基保护基,R4 和 R5 可以相同或不同,各自代表氢原子或羧基保护基)或其盐及其制备方法。