基于抗菌氟喹诺酮的作用靶拓扑异构酶与哺乳动物的相似性,为寻找由抗菌活性到抗肿瘤活性转化的有效修饰方法,用(噁)二唑杂环作为诺氟沙星(1)的羧基电子等排体得中间体,1-乙基-6-氟-7-(哌嗪-1-基)-3-(5-巯基-1,3,4-(噁)二唑-2-基)-喹啉-4(1H)-酮(3),化合物3与氯甲基(噁)二唑(4a ～4e)进行S-醚化得双(噁)二唑甲硫醚(5a～5e),再进一步甲基化和季铵化得相应的N-甲基双(噁)二唑甲硫醚(6a～6e)和N,N-二甲基双(噁)二唑甲硫醚碘化物(7a～7e).双(噁)二唑甲硫醚目标物的结构经元素分析、1 H NMR、MS技术确证.采用MTT 法评价了目标化合物对体外培养人肝癌细胞株Hep-3B生长的抑制活性.结果表明,15个目标化合物的抑制活性均显著高于对照化合物1的抑制活性,其季铵盐的IC50值低于25.0 μmol/L,显示出潜在的抗癌活性.%To discover an efficient modification for shifting from an antibacterial fluoroquinolone to an antitumor one based on the topological similarities between targeting topoisomerases as the eukaryotic ones and mammals, using oxadiazole heterocycle as an intermediate for the isostere of C-3 carboxylic group of norfloxacin( 1) , 1-ethyl-6-fluoro-7-piperazin-1-yl-3-(5-mercapto-1,3,4-oxadiazol-2-yl)-quinolin-4( 1H)-one (3) was subjected to thioetherfication with each of chloromethyl oxadiazole(4a ~4e) to give bis-oxadiazole methylsulfides (5a ~ 5e) , respectively. The following N-methylations and quaternizations yielded the corresponding N-methyl bis-oxadiazole methylsulfides (6a ~ 6e) and N, N-dimethyl bis-oxadiazole methylsulfide iodides (7a ~7e). The structures of fifteen title compounds were characterized by elemental analysis, 1H NMR and MS, and their anticancer activities in vitro against Hep-3B cancer cell lines were also evaluated with a MTT assay. The results reveal that fifteen title compounds show higher cytotoxicity than that of comparison 1, in which quaternary ammonium salts exhibit potential anticancer activity with IC50 values below 25.0 μmol/L.
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