Supported Ionic Liquid H2PMo12O40-NMPIL@SiO2 as an Efficient Catalyst for Alkylation of Indoles with Epoxides or Alcohols under Mild Conditions

3-Alkylindoles have been prepared in 91~99% excellent yields by alkylation of indoles with epoxides or alcohols catalyzed by the recyclable heteropoly acid based supported functionalized ionic liquid H₂PMo₁₂O₄₀-NMPIL@SiO₂under heterogeneous catalysis atroom temperature. The influence of various reaction parameters including catalyst selection, catalyst amount, reaction time, solvent, and reaction temperature were studied. The heterogeneous supported catalyst was easily recoverable by filtration, and could be used for six consecutive runs without significant loss in catalytic activity. This study demonstrated a green and highly efficient chemistry technology in the preparation of 3-alkylindoles.