Sulphamic Acid—A Mild, Efficient, and Cost‐Effective Solid Acid Catalyst for the Synthesis of Bis(1H‐indol‐3‐yl)methanes

Abstract

Abstract Sulphamic acid (SA) is found to efficiently catalyze the electrophilic substitution reactions of indoles with aldehydes and ketones in ethanol to afford the corresponding bis(indolyl)methanes. The method is simple and cost effective, and gives good yields in short reaction times. The catalyst is found to be recyclable.