An efficient one-pot synthesis of bis-indolylmethanes containing pyrazolyl catalyzed by Br?nsted acidic ionic liquid under solvent-free conditions

摘要

Figure represented. Br?nsted acidic ionic liquid [PyNCH _2CO_2H][HSO_4] was found to be an effective catalyst for the condensation reactions of indoles with various 4-formylpyrazoles to afford the corresponding bis-indolylmethanes containing pyrazole under solvent-free conditions. The satisfactory results were obtained with excellent yields, short reaction time, and simplicity in the experimental procedure.