Synthesis of bis(indolyl)methanes catalyzed by surface modified zirconia

The efficiency of phosphated zirconia, a solid acid catalyst for the synthesis of bis(indolyl)methanes (BIM) was determined. The reaction was carried out under mild and solvent free conditions and the acid catalyst could be easily separated and reused. The characterization of the catalysts was carried out using XRD and FT-IR and the characterized phosphated zirconia catalysts were used for synthesis. Effect of various parameters such as calcination temperature, phosphoric acid concentration, solvents, reaction temperature and catalyst loading has been studied. (c) 2008 Elsevier B.V. All rights reserved.