Catalytic activity of the nanoporous MCM-41 surface for the Paal–Knorr pyrrole cyclocondensation

Abstract

The investigation of different oxide surfaces revealed that nanoporous silica (MCM-41) had the best catalytic activity for Paal-Knorr pyrrole synthesis. Despite the same composition, MCM-41 proved to be more effective than SiO 2 itself, probably due to a significantly higher surface area of the SiO 2 nanopores. The important features of this "clean" solvent-free protocol are the ease of recovery and the reuse of the catalyst for several cycles, operational simplicity, and easy product isolation and purification.