Efficient FeIII-catalyzed synthesis of bis(indolyl)methanes in ionic liquids

An efficient synthesis of bis(indolyl) methanes through Fen(III)-catalyzed electrophilic substitution reactions of indoles with various aldehydes in ionic liquid is described. It was found that the ionic liquids involving FeCl(3)(.)6H(2)O were the most efficient catalytic systems, and could be simply recycled without significant loss of activity. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)