Abstract
Efficient electrophilic substitution reactions of indoles with various aromatic aldehydes were carried out using a catalytic amount of ZnO under solvent‐free conditions to afford the corresponding bis(indolyl)methanes in excellent yields. Among the various methods published for the synthesis of bis(indolyl)methane, ZnO is a very cheap, environmentally friendly, and reusable catalyst that can be used for synthesis of a new range of bis(indolyl)methane derivatives.
Acknowledgments
We gratefully acknowledge the support of this work by Shiraz University. We are also grateful to Prof. H. Sharghi for synthesis of aldehyde 1q and his helpful cooperation.