An Efficient Procedure for the Synthesis of Polysubstituted Pyrroles in an Ionic Liquid

Abstract

The ionic liquid 1-butyl-3-methyl-imidazolium hydrogen sulfate, [bmim]HSO4, was used as a catalyst and reaction medium for the pyrrole synthesis, and a wide range of aliphatic, aromatic, heteroaromatic and carboxylic 1,4-diketones easily underwent condensations with aniline and ethylenediamine to form polysubstituted pyrroles. Sequential decarboxylation/Paal-Knorr pyrrole condensation was observed, which provides a new and facile approach to monoester pyrroles from 1,4-diketo-2,3-dicarboxylic acid esters.