A Solvent-Free Synthesis of Imidazo[1,5-a]pyridines Using CCl4 as an Oxidant

Abstract

Imidazo[1,5-a]pyridines are intriguing molecules known for their unique biological and photophysical properties, making them valuable in medicinal chemistry. This study reports a solvent-free approach for synthesizing 3-arylimidazo[1,5-a]pyridines 1a-q using carbon tetrachloride as an oxidant reagent and DBU as a base, affording good to high product yields. Based on control experiments, kinetic analysis conducted by ¹³C NMR and DFT calculations, we propose a plausible reaction pathway to elucidate this transformation. Moreover, we demonstrate that CCl₄ is a chloride donor and oxidant by observing the formation of CHCl₃ as a byproduct.