An Efficient One-Pot, Three-Component Synthesis of Tetrasubstituted Pyrroles under Catalyst- and Solvent-Free Conditions

An environmentally benign, catalyst-and solvent-free, three-component synthesis of tetrasubstituted pyrroles was estab-lished. The reaction proceeds via a nucleophilic attack of primary amine on dialkyl acetylenedicarboxylate followed by Michael addition with f3-nitrostyrene and successive intramolecular cyclization and aromatiza-tion to yield 1,2,3,4-tetrasubstituted pyrroles in good to excellent yields. A wide range of primary amines including aromatic amines and benzylamines were coupled with differently substituted f3-nitrostyrenes and dialkyl acetylenedicarboxylate. Furthermore, compared to previous reported methods, the present study is highly atom economical and environmentally benign and can be scaled up.