ABSTRACT Rongalite, an inexpensive industrial product, has been found to be an efficient promoter for the preparation of bis(indolyl)methanes from arylaldehydes and indoles. The desired products were usually isolated in excellent yields from the reaction mixture by filtration after dilution with water. However, the condensation reaction did not take place with aliphatic and some heteroaromatic aldehydes.
John et al. (Wed,) studied this question.