Visible-light-mediated C-H amidation of imidazoheterocycles with N-amidopyridiniums.

C-3 amidated imidazoheterocycles were synthesized via a visible light-promoted reaction of imidazoheterocycles with N-amidopyridinium salts catalyzed by 4CzIPN under mild conditions. For imidazoheterocycles and N-amidopyridinium salts with various substituents, the reaction proceeded smoothly to give the corresponding products in moderate to good yields. The reaction provides a new strategy for the synthesis of secondary amides with the imidazo[1,2-a]pyridine core.