Studies on Anti-MRSA Parenteral Cephalosporins. II. Synthesis and Antibacterial Activity of 7.BETA.-[2-(5-Amino-1,2,4-thiadiazol-3-yl)-2(Z)-alkoxyiminoacetamido]-3-(substituted imidazo [1,2-b]pyridazinium-1-yl)methyl-3-cephem-4-carboxylates and Related Compounds.
作者:TOMOYASU ISHIKAWA、KJEIJI KAMIYAMA、NOBUYUKI MATSUNAGA、HIROYUKI TAWADA、YUJI IIZAWA、KENJI OKONOGI、AKIO MIYAKE
DOI:10.7164/antibiotics.53.1071
日期:——
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。