Sami Sajjadifar - Department of Chemistry, Payame Noor University, P.O. Box 19395-4697 Tehran, Iran
Ghobad Mansouri - Department of Chemistry, Payame Noor University, P.O. Box 19395-4697 Tehran, Iran
Shefa Miraninezhad - Department of Chemistry, Payame Noor University, P.O. Box 19395-4697 Tehran, Iran

Silica supported-boron sulfonic acid was used as a cheap and mild bronsted acidic in the reaction of indole with aldehydes or indole aldehydes to afford the corresponding bis(indolyl)methanes in solvent free grinding and room temperature. The catalyst is also effective in the reaction in good yields. This methodology offers several advantages, such as good yields, reusability of catalyst, short reaction times, simple procedure, and mild conditions. The catalyst can be recovered and reused without loss of activity. The work-up of the reaction consists of a simple filtration, followed by concentration of the crude product and purification

Indole, Bis(indolyl)methane, Boron Sulfonic Acid, Aldehyde, Synthesis, Solventfree