A novel and efficient synthesis of bisindolylmethanesby using silica-supported-3-(triethoxysilyl) propane-1-ammonium chloride as a reusable catalyst under solvent free conditions

A facile and efficient synthesis of bis(indolyl)methanes derivatives (3a-u) was reported via a condensation reaction of aldehydes and indole in the presence of silica-supported-3-(triethoxysilyl) propane-1-ammonium chloride catalysis under solvent free conditions. We studied the model reaction in different conditions, temperature, and amount of optimized catalyst. The use of just 0.02 g of (silica gel-ammonium salt) is sufficient. The reaction was carried out at 110°C under thermal condition. This method includes some advantages such as mild reaction condition, easy work-up, and recoverable and reusable catalyst.