Glycerin and CeCl3·7H2O: a new and efficient recyclable medium for the synthesis of bis(indolyl)methanes

Glycerin and CeCl3·7H2O were successfully used in recyclable catalytic system for the synthesis of several bis(indolyl)methanes in good to excellent yields through the reaction of indoles with aldehydes. The method is applicable to aliphatic and aromatic aldehydes, and the mixture of glycerin and CeCl3·7H2O can be reused up to five times without special treatment and with comparable yields.