p-Toluenesulfonic acid doped polystyrene (PS-PTSA): solvent-free microwave assisted cross-coupling-cyclization-oxidation to build one-pot diversely functionalized pyrrole from aldehyde, amine, active methylene, and nitroalkane

A solvent-free environmentally benign approach for the synthesis of diversified pyrrole derivatives has been described by the one-pot multicomponent reaction of aldehydes, nitroalkane, amine, and enolizable active C-H reactant using polystyrene supported p-toluenesulfonic acid (PS-PTSA) under microwave irradiation. In comparison to the conventional methods, this efficient green protocol provides remarkable advantages such as good to excellent yields, shorter reaction time, low cost, easy work-up procedure, and bypass for use of hazardous transition metal catalyst and organic solvent. (C) 2014 Elsevier Ltd. All rights reserved.