An Efficient Nickel Chloride Catalyzed Multi-Component Condensation of Indole with Carbonyl Compounds in PEG-400 as a Green Medium at Ambient Conditions

Bis (indolyl) methane derivatives were efficiently synthesized by the condensation reaction of various aromatic aldehydes and indole in presence of nickel chloride as a Lewis acid catalyst in PEG-400 as a recyclable green solvent at room temperature. The use of PEG-400 and nickel chloride offers improvements for the synthesis of bis (indoyl) methanes with regard to the yield of products, short reaction times and green aspects utilizing recyclable and non volatile medium and avoiding any volatile and hazardous organic solvent.