Efficient and Eco‐Friendly Process for the Synthesis of Bis(1H‐indol‐3‐yl)methanes using Ionic Liquids

Abstract Indoles react smoothly with carbonyl compounds in 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([bmim]BF4) or 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([bmim]PF6) ionic liquids under mild reaction conditions to afford the corresponding bis‐indolylmethanes in excellent yields. These ionic liquids can be recovered and recycled in subsequent reactions without any apparent loss of activity.