Green and Rapid Strategy for Synthesis of Novel and Known Pyrroles by the Use of Molybdate Sulfuric Acid

Molybdate sulfuric acid as a highly efficient catalyst has been employed for the modified Paal-Knorr synthesis of some novel and known pyrroles under solvent-free conditions. Catalyst loads as low as 1 mol% could be used leading to high yields of pure pyrrole derivatives at an oil bath temperature of 60 degrees C. This method has advantages such as the use of very low amounts of a recyclable catalyst, avoidance of organic solvents, and high product yields.