Solvent Free Synthesis of N-Substituted Pyrrole Derivatives Catalyzed by Silica Sulfuric Acid

Sulfuric acid immobilized on silica gel is used as an efficient catalyst in the synthesis of N-substituted pyrrole derivatives by the Clauson–Kaas pyrrole synthesis. The solvent free reaction mixture is stirred by grinding. Within very short reaction time the process leads to the corresponding products without any decomposition recorded.