Bleaching Earth Catalyzed Synthesis of Bis (Indolyl) Methane’s Derivatives in (Polyethylene Glycol) PEG-400

Synthesis of bis(indolyl) methanes by the reaction of indoles with structurally diverse aldehydes and cyclohexanone in the presence of catalytic amount of bleaching earth in polyethylene glycol (PEG-400) as green solvent afforded the corresponding bis(indolyl) methanes in excellent yields. The effects of solvent, nature of substituents on the aromatic ring of aldehydes were investigated. The catalysts and solvent were reusable up to 4 times without significant loss of activity. The remarkable features of this procedure are high conversions, shorter reaction time and cleaner reaction profiles.