Transition-metal-free C-H amidation and chlorination: synthesis of N/N'-mono-substituted imidazopyridin-2-ones from N-pyridyl-N-hydroxylamine intermediates.

Non-symmetric 1,3-substituted imidazopyridin-2-ones are a common structural scaffold found among many biologically active molecules. Herein we report an efficient, mild, and transition-metal free C-H amidation strategy to access such a pyrido-fused cyclic urea framework in good yields and with a broad functional group tolerance.