Convenient synthesis of polysubstituted pyrroles and symmetrical and unsymmetrical bis-pyrroles catalyzed by H3PW12O40

Abstract

A mild and environmentally-benign protocol for the efficient synthesis of polysubstituted pyrroles via a one-pot three-component reaction of amines, α-bromo ketones and dialkyl acetylenedicarboxylate using H 3 PW 12 O 40 as a recyclable heterogeneous catalyst under solvent-free conditions at room temperature is reported. Importantly, the synthesis of symmetrical and unsymmetrical polysubstituted bis-pyrroles has been performed in good yields for the first time, which can be considered as a salient feature of this protocol. A mild and environmentally-benign protocol for the synthesis of polysubstituted pyrroles, and symmetrical and unsymmetrical bis-pyrroles in the presence of H 3 PW 12 O 40 as a non-corrosive, inexpensive and reusable catalyst under solvent-free conditions at room temperature is reported.