Catalyst-Free Regioselective C-3 Nitrosation of Imidazopyridines with tert-Butyl Nitrite under Neutral Conditions

Abstract

We have successfully developed a novel and efficient catalyst-free method for the synthesis of 3-nitroso-substituted imidazopyridines, from readily available imidazo[1,2-a]pyridines and tert-butyl nitrite, in good to excellent yields. Importantly, the use of transition-metal catalysts, stoichiometric amounts of acids, and toxic or potentially dangerous oxidants is avoided. This easy and practical method complements nitrosation reactions by expanding the scope and practicality, and should attract much attention in synthetic and pharmaceutical chemistry.