Solvent-free multi-component synthesis of unsymmetrical bis(indolyl)alkanes with Lewis acid-surfactant-SiO2 as nanocatalyst

Abstract

Herein we report the multicomponent synthesis of the bis(indolyl)methane derivatives in a ball mill. The reaction was carried out under solvent-free conditions using only the Lewis acid-surfactant-SiO2 composite nanocatalyst (LASSC) prepared in situ. The unsymmetrical bis(indolyl) methane derivatives containing nitro or fluorine substitution with a yield of 72%–92% were obtained in a short reaction time. Within we verified that under the action of the combined catalyst of AlCl3·6H2O + SDS + SiO2, the method of preparing unsymmetrical bis(indolyl)methane by mechanical grinding without solvent has obvious advantages. Finally, we inspected that the catalysis system can be used eight times without a significant decrease in activity.