Efficient and Green Synthesis of Bis(indolyl)Methanes using Thiamine Hydrochloride as an Organocatalyst: A Parallel Scrutiny of Microwave Irradiation versus Ultrasonicator Heating in Water

Thiamine hydrochloride is reported to be a highly competent promoter for the synthesis of bis(indolyl)methanes under solvent free conditions using microwave irradiation and ultrasonicator heating in aqueous media. Vitamin B1 is an economical, non-toxic, nonflammable and water soluble green organocatalyst. Moreover, the simple approach, easily operational, short reaction time, high yield and using a little quantity of thiamine hydrochloride makes this method an alternative approach. Present protocol is a simple and eco-friendly approach for the synthesis of bis(indolyl)methanes under microwave and ultrasonicator conditions.