Chinese Journal of Catalysis ›› 2013, Vol. 34 ›› Issue (6): 1187-1191.DOI: 10.1016/S1872-2067(12)60571-3

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Hydroxyalkylation of indole with cyclic carbonates catalyzed by ionic liquids

GAO Guohua, ZHANG Lifeng, WANG Binshen   

  1. Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062, China
  • Received:2012-12-20 Revised:2013-03-12 Online:2013-06-07 Published:2013-06-09
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (20873041,21273078) and the Shanghai Leading Academic Discipline Project (B409).

Abstract:

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.

Key words: Ionic liquid, Indole, Cyclic carbonate, Hydroxyalkylation