An environmentally benign, catalyst- and solvent-free, three-component synthesis of
tetrasubstituted pyrroles was established. The reaction proceeds via a nucleophilic
attack of primary amine on dialkyl acetylenedicarboxylate followed by Michael addition
with β-nitrostyrene and successive intramolecular cyclization and aromatization 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 β-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.
Key words
pyrrole - multicomponent reaction - solvent- free - catalyst-free - green synthesis
