氯化胆碱催化醛、吲哚和丙二腈的三组分Yonemitsu缩合反应

Choline Chloride as Catalyst towards the Attractive Yonemitsu Reaction of Benzaldehyde, Indole, and Malononitrile

在乙醇和水的混合溶液中,使用廉价易得的氯化胆碱催化苯甲醛、丙二腈和吲哚的三组分Yonemitsu缩合反应,高产率地合成了一系列3-取代吲哚衍生物.实验结果表明,水的引入对该反应有很好的促进作用.由于催化剂极易溶于乙醇水溶液,大部分反应结束后只需要经过简单的抽滤和淋洗就可以达到分离和提纯的目的,避免了繁琐的后处理程序.催化剂可以循环使用5次,活性没有降低.

Using choline chloride as cheap and safe accelerator was efficient to promote the Yonemitsu type condensation of indole, benzaldehyde, and malononitrile. More importantly, introducing right amount of water in reaction system was crucial to get desired 3-substituted indoles in good to excellent yields. Due to the catalyst has excellent solubility in aqueous ethanol, the final concoction was easy to separate. Many desired products could be obtained after filtration and washed with cold aqueous ethanol without further purification. Catalyst could further reuse for five more reaction cycles with negligible loss in activity.