In an effort to discover a novel cefozopran (CZOP) derivative having excellent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), we performed chemical modification of the alkoxyimino moiety and imidazo[1, 2-b]pyridazinium group of CZOP. Among the prepared compounds, the cyclopentyloxyimino derivative 7β-[2-(5-amino-1, 2, 4-thiadiazol-3-yl)-2(Z)-cyclopentyloxyiminoacetamido]-3-(3, 6-diaminoimidazo[1, 2-b]pyridazinium-l-yl)methyl-3-cephem-4-carboxylate (20g) showed the most potent anti-MRSA activity, reflecting its high affinity (IC50=1.6 μg/ml) for penicillin binding protein 2' (PBP2'), although its anti-MRSA activity was slightly inferior to that of vancomycin (VCM). In experimental systemic infection in mice, however, 20g showed activity comparable to that of VCM against MRSA. In addition, 20g showed activity similar or slightly inferior to that of CZOP against Pseudomonas aeruginosa both in vitro and in vivo. Considering its favorable antibacterial activity profile, 20g was considered to be the most promising CZOP derivative for further studies.
为了发现一种对耐
甲氧西林金黄色葡萄球菌(MRSA)具有出色抗菌活性、新颖的头孢唑普兰(
CZOP)衍
生物,我们对
CZOP的烷氧亚
氨基部分和
咪唑并[1,2-b]
哒嗪鎓基团进行了
化学修饰。在制备的化合物中,环戊氧亚
氨基衍
生物7β-[2-(
5-氨基-1,2,4-噻二唑-3-基)-2(Z)-环戊氧亚
氨基乙酰胺基]-3-(3,6-二
氨基
咪唑并[1,2-b]
哒嗪鎓-1-基)甲基-3-头孢烯-4-
羧酸酯(20g)表现出最强的抗MRSA活性,反映其对
青霉素结合蛋白2'(PBP2')的高亲和力(IC50=1.6μg/ml),尽管其抗MRSA活性略逊于
万古霉素(
VCM)。然而,在小鼠实验性系统感染中,20g对MRSA表现出与
VCM相当的活性。此外,20g无论在体外还是体内,对
铜绿假单胞菌(Pseudomonas aeruginosa)的活性与
CZOP相似或略逊。综合其良好的抗菌活性特征,20g被认为是最有希望的
CZOP衍
生物,值得进一步研究。