Convenient synthesis of substituted pyrroles via a cerium (IV) ammonium nitrate (CAN)-catalyzed Paal–Knorr reaction

A screening of various cerium salts for promoting the Paal–Knorr pyrrole synthesis revealed the superiority of cerium (IV) ammonium nitrate (CAN) as a catalyst. Excellent yields of substituted pyrroles were obtained in CAN-catalyzed Paal–Knorr reactions of 1,4-diketones with various amines. The protocol is noteworthy for the mild reaction condition, short reaction times, scalability and easy isolation of products and high yields of the products.