Metal-free selective synthesis of 2-substituted benzimidazoles catalyzed by Brönsted acidic ionic liquid: Convenient access to one-pot synthesis of N-alkylated 1,2-disubstituted benzimidazoles
作者:Warapong Senapak、Rungnapha Saeeng、Jaray Jaratjaroonphong、Vinich Promarak、Uthaiwan Sirion
DOI:10.1016/j.tet.2019.05.014
日期:2019.6
A novel efficient method for the selective synthesis of 2-substituted benzimidazoles is described through condensation reaction of o-phenylenediamines with a wide rang of aliphatic, aromatic and heteroaromatic aldehyde substrates using Brönsted acidic ionic liquid as a reusable catalyst under metal-free conditions at ambient temperature. Notably, Dodecylimidazolium hydrogen sulfate ([DodecIm][HSO4])
描述了一种新的有效的选择性合成2-取代的苯并咪唑的有效方法,该方法通过邻苯二胺与多种脂族,芳族和杂芳族醛底物的缩合反应,使用布朗斯台德酸性离子液体作为可重复使用的催化剂,在室温下于无金属条件下进行温度。值得注意的是,十二烷基咪唑硫酸氢盐([DodecIm] [HSO 4 ])是最有效的催化剂,其相应产品的产率高至优异(高达98%)。随后,该协议成功地应用于用于制备Ñ烷基化1,2-二取代的苯并咪唑在高以优异的产率通过顺序一锅反应。另外,催化剂被循环至少四次而没有明显的活性损失。