离子液体催化吲哚羟烷基化反应(英文)

Hydroxyalkylation of indole with cyclic carbonates catalyzed by ionic liquids

报道了咪唑类离子液体催化吲哚和环状碳酸酯反应合成羟烷基吲哚,系统考察了反应时间、催化剂用量、反应温度和反应物比例对离子液体催化反应性能的影响.在优化的反应条件下,吲哚与碳酸乙烯酯或碳酸丙烯酯反应可高效地生成1-(2-羟乙基)吲哚、1-(2-羟丙基)吲哚及其相应的衍生物.离子液体的催化活性与离子液体中的阴离子有关,其催化活性顺序为BF4–﹤Br–﹤Cl–﹤OAc–,与阴离子的碱度顺序一致.

A simple and eco‐friendly procedure has been developed for the synthesis of hydroxyalkyl indoles from indole and cyclic carbonates in the presence of a catalytic amount of imidazolium based ionic liquids under solvent‐free conditions. The effects of reaction time, the catalyst amount, temperature, and the ratio of the reactants were investigated to develop the optimum conditions for the transformation. Under the optimized reaction conditions, indole reacted with ethylene carbonate or propylene carbonate to give 1‐(2‐hydroxyethyl)indole or 1‐(2‐hydroxypropyl)indole, as well as the corresponding sequential derivatives, in high yields. The catalytic activity of the ionic liquids was affected by the anions of the ionic liquids in the order of BF4–< Br–< Cl–< OAc–, which was consistent with the hydrogen bond basicity of the anions of the ionic liquids.