Multi-walled carbon nanotubes sulfuric acid as a reusable heterogeneous solid acid catalyst for the rapid synthesis of imidazo[1,2-a]pyridines

Abstract

Multi-walled carbon nanotubes sulfuric acid as a reusable heterogeneous stable solid acid catalyst was synthesized from a facile sulfonation of hydroxyl multi-walled carbon nanotubes with chlorosulfonic acid at 0 °C during 2 h. The synthesized catalyst was found to be a highly efficient heterogeneous catalyst for the Groebke-type synthesis of imidazo[1,2-a]pyridines through a condensation reaction of an aldehyde, a 2-aminopyridine, and an isocyanide in methanol in excellent yields with short reaction times at room temperature. The catalyst could be easily recovered by simple filtration and reused without losing its activity. Multi-walled carbon nanotubes sulfuric acid as a reusable heterogeneous solid acid catalyst for the rapid synthesis of imidazo[1,2-a]pyridines .