ZrOCl2•8H2O as a highly efficient, eco-friendly and recyclable Lewis acid catalyst for one-pot synthesis of N-substituted pyrroles under solvent-free conditions at room temperature

A new and efficient method for the synthesis of a variety of N-substituted pyrroles from condensation reactions of 2,5-hexanedione with amines or diamines using ZrOCl2 center dot 8H(2)O as a water-tolerant Lewis acid catalyst at room temperature is described. The use of nontoxic, inexpensive, easily available and reusable catalyst under solvent-free conditions make this protocol practical, environmentally friendly and economically attractive. Copyright (C) 2011 John Wiley & Sons, Ltd.