N-[4-(苯并咪唑-2-硫基)苯基]-N'-烷基胍类衍生物的合成和生物活性

为了寻找对诱生型一氧化氮合酶(inducible nitric oxide synthase，iNOS)有抑制活性的新型化合物，设计合成了一系列N-［4-(苯并咪唑-2-硫基)苯基］-N′-烷基胍类衍生物(I₁～I₁₂)。以2-巯基苯并咪唑(1)为原料，经缩合和还原得到2-(4-氨基苯硫基)苯并咪唑(3)，再与异硫氰酸苯甲酰酯反应得双取代硫脲(4)，4经水解和S-烷基化得到关键中间体S-乙基-n-［4-(苯并咪唑-2-硫基)苯基］异硫脲氢碘酸盐(6)，6与伯胺或仲胺反应得目标化合物I₁～I₁₂。这些化合物的结构经IR，¹H NMR，MS和元素分析得到确证。初步的iNOS抑制活性测定结果显示，3个化合物(I₁，I₈和I₁₀)的活性强于阳性对照药氨基胍，其中化合物I₁的活性是氨基胍的5.5倍。

Synthesis and bioactivity of N-[4-(benzimidazole-2-thio)phenyl]-N''-alkyl guanidine derivatives

In order to get some novel compounds with potent iNOS inhibitory activity, 12 target compounds of N-[ 4-( benzimidazole-2-thio) phenyl ] -N'-alkyl guanidine derivatives ( I1- I12 ) were synthesized from 1-benzoyl-3-[ 4-( benzimidazole-2-thio) phenyl] thioureas (4) by hydrolysis with 2. 0 mol x L(-1) sodium hydroxide solution containing tetrahydrofuran to form the corresponding N-[ 4-(benzimidazole-2-thio) phenyl] thioureas (5) which was S-ethylated with ethyl iodide, followed by amination with primary amines or secondary amines. The intermediate 4 was synthesized from 2-mercaptobenzimidazole (1) by reaction with 1-chloro-4-nitrobenzene to form 2-( 4-nitrophenylthio) benzimidazole (2) which was reduced by iron powder and hydrochloric acid, followed by reaction with benzoyl isothiocyanate. The structures of compounds I1 - I12 were confirmed by IR, MS,1H NMR and elemental analysis. The results of preliminary pharmacological test showed that the activities of three compounds (I 1, I8 and I10) were stronger than aminoguanidine, especially for compound I1.