Efficient Synthesis of Bis(indolyl)methane Derivatives on Heterogeneous Ga-MCM-41-SO3H Catalyst under Mild Conditions

Abstract

We are reporting a convenient method for the synthesis of bis(indolyl)methane derivatives from relatively cheap and commercially available chemicals such as indoles and aldehydes in a one-pot procedure using Ga-MCM-41-SO3H heterogeneous catalyst. Notably, the use of this catalyst has resulted in high yield of products (up to 98 %) under mild conditions, and the catalyst was found to be stable and reusable, retaining its highly catalytic activity even after five runs. Interestingly, two alkaloids Arsindoline A and Turbomycine B were successfully synthesized in the employment of this catalyst. These findings suggest that Ga-MCM-41-SO3H could be a promising alternative to traditional acid homogeneous catalysts in the synthesis of bis(indolyl)methane derivatives, offering several advantages including ease of separation and reuse, high stability, and low toxicity.