Oxidative Sulfonamidomethylation Of Imidazo [1,2-α] Pyridines

An efficient three-component syntheses of C3 sulfonamidomethylation of imidazopyridines has been disclosed.This reaction utilized imidazo[1,2-α]pyridine as the reaction substrate,sulfonamides,anilines and amines as the amine source,methanol（CH₃OH）as the main methylene source,hexafluoroisopropanol（HFIP）and methanol as the solvent,potassium permanganate（KMnO₄）and tert-Butylperoxide（DTBP）as the co-oxidant,and sodium tert-butoxide（NaO^tBu）as the base,to access one pot syntheses of C3 sulfonamidomethylated imidazopyridines.The current methodology featured several advantages,including broad substrate scope,good functional group tolerance and high reaction efficiency.The main research contents are as follows:The reaction of 2-Phenylimidazo[1,2-α]pyridine and benzenesulfonamide was employed as model reaction.After a survey of various reaction conditions for sulfonamidomethylation,the optimized reaction conditions was obtained.A wide range of substituted imidazopyridines sulfonamides,anilines and amines were well tolerated to afford the corresponding products in up to 92%yield under optimal conditions（Scheme 1）.On the basis of control experiments and isotope labeling,the possible reaction mechanism was proposed.