The synthesis of a series of novel 4-substituted 2,3,6,7-tetrahydrobenzo [1,2-b;4,5-b']difuran-1H-imidazolium salts is presented. The biological properties of the compounds were evaluated in vitro against a panel of human tumor cell lines. Results suggest that the 5,6-dimethyl-benzimidazole or 2-methyl-benzimidazole ring, and substitution of the imidazolyl-3-position with a 2-naphthylmethyl substituent or 2-naphthylacyl substituent, were important to the cytotoxic activity. Notably, 3-(2-Naphthylmethyl)-1-((2,3,6,7-tetrahydrobenzo[1,2-b;4,5-b']difuran-4-yl)methyl)-1H-5,6-dimethyl-benzimidazol-3-ium bromide (42) was found to be the most potent derivative against five human tumor cell lines with IC50 values of 1.06-4.34μM and more selective towards SMMC-7721, A549 and SW480 cell lines. 3-(2-Naphthylacyl)-1-((2,3,6,7-tetrahydrobenzo[1,2-b;4,5-b']difuran-4-yl)methyl)-1H-2-methyl-benzimidazol-3-ium bromide (37) showed higher selectivity to SMMC-7721 and MCF-7 cell lines with IC50 values 2.7-fold and 8.4-fold lower than DDP. Study regarding to the antitumor mechanism of action showed that compound 37 could induce cell cycle G1 phase arrest and apoptosis in SMMC-7721 cells.

中文翻译：

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新型四氢苯并二呋喃-咪唑鎓盐衍生物的合成及细胞毒活性。

提出了一系列新颖的4-取代的2,3,6,7-四氢苯并[1,2-b; 4,5-b']二呋喃-1H-咪唑鎓盐的合成。在体外针对一组人类肿瘤细胞系评估了化合物的生物学特性。结果表明5，6-二甲基苯并咪唑环或2-甲基苯并咪唑环以及用2-萘甲基取代基或2-萘甲酰基取代基取代咪唑基-3-位对于细胞毒性活性是重要的。值得注意的是，3-（2-萘基甲基）-1-（（（2,3,6,7-四氢苯并[1,2-b; 4,5-b']二呋喃-4-基）甲基）-1H-5，发现六甲基二甲基苯并咪唑-3-溴化铵（42）是针对五种人类肿瘤细胞系的最有效衍生物，IC50值为1.06-4.34μM，对SMMC-7721，A549和SW480细胞系更具选择性。3-（2-萘甲酰基）-1-（（（2,3,6,7-四氢苯并[1,2-b; 4，5-b']二呋喃-4-基）甲基）-1H-2-甲基苯并咪唑-3-溴化铵（37）对SMMC-7721和MCF-7细胞系表现出更高的选择性，IC50值分别为2.7倍和8.4 -低于DDP。关于抗肿瘤作用机理的研究表明，化合物37可以诱导SMMC-7721细胞的细胞周期G1期停滞和凋亡。