An easy synthesis of 1-aryl-1H-4,5-dihydroimidazoles 1 by cyclocondensation of N-aryl-N′-formylethylenediamines 2 is described. Such precursors were synthesized by selective formylation of N-arylethylenediamines 3 with p-nitrophenyl formate. Cyclizations were performed using trimethylsilyl polyphosphate. Chemical properties of compounds 1, typical of amidine system, were studied. Reaction of 1 with methyl iodide leads to the corresponding 1-aryl-3-methyl-1H-4,5-dihydroimidazolium salts 5. Reduction of dihydroimidazoles 1 with sodium cyanoborohydride provides a convenient access to N-aryl-N′-methylethylenediamines 4.
本文介绍了通过 N-芳基-N′-甲酰基
乙二胺 2 的环缩合,轻松合成 1-芳基-1H-4,5-二氢
咪唑 1 的方法。这种前体是通过 N-芳基
乙二胺 3 与
对硝基苯甲酸酯的选择性甲酰化合成的。使用三甲基
硅基聚
磷酸酯进行了环化。研究了化合物 1 的
化学特性,它是典型的脒系统。1 与
碘甲烷反应生成相应的 1-芳基-3-甲基-1H-4,5-二氢
咪唑鎓盐 5。用
氰基硼氢化钠还原二氢
咪唑 1 可以方便地得到 N-芳基-N′-甲基
乙二胺 4。