Room-Temperature Transition-Metal-Free One-Pot Synthesis of 3-Aryl Imidazo[1,2-a]pyridines via Iodo-hemiaminal Intermediate

摘要

A mild and efficient one-pot synthesis of 3-aryl imidazo[1,2-alpha]pyridines in up to 88% yield was developed. An adduct was formed after the simple mixing of 2-amino-4-methylpyridine, 2-phenylacetaldehyde, and N-iodosuccinimide in CH2Cl2, and the structure of the adduct was characterized by 2D NMR, IR, and high-resolution mass analysis. The adduct was readily cyclized by treatment with a saturated aqueous solution of NaHCO3. The reactions proceeded to completion after several hours at room temperature.