Nano BF3/SiO2: A Novel Acid Catalyst for the Synthesis of Pyrroles by the Paal–Knorr Condensation at Room Temperature

Pyrroles are the important five-membered nitrogen heterocyclic compounds, which can be used as intermediates in many organic reactions and are important in fine chemical industry, particularly in the synthesis of many important drugs[1]. The laboratory methods for pyrrole synthesis by many organic chemist such as Knorr[2]. Due to the efficient, mild reaction condition and facile reaction process, the Paal– Knorr condensation reaction remains the most frequently used one to generate pyrrole and its derivatives[3]. In this reaction, the N-substituted pyrrole could be obtained through condensation of 2,5-hexanedione with aniline derivatives in one step. We wish to report herein a simple, clean, and environmental eco friendly process for the synthesis of pyrrole derivatives by nano BF3/SiO2 as heterogenious catalyst under solvent-free condition at room temperature(Scheme1).