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Benzimidazol-2-ones have various biological functions and are usually prepared by reactions of substituted benzene-1,2-diamines with carbonyl-containing compounds or intramolecular N-arylations using substrates with carbon-halogen bonds. However, the starting materials of these protocols are often not readily available. Herein, a simple and practical metal-free oxidative C-H amidation of N, N′-diarylureas has been developed that takes place at room temperature. This protocol uses readily available N, N′-diarylureas as the starting materials and inexpensive PhI(OAc)2 as the oxidant without the need of a catalyst, ligand, or the exclusion of air. The present method has a wide functional group tolerance and affords a new and practical strategy for the synthesis of N-heterocycles. [ABSTRACT FROM AUTHOR]

A novel, efficient, and practical method for the synthesis of imidazopyridine derivatives has been developed through the copper-catalyzed aerobic oxidative CH functionalization of substituted pyridines with N-(alkylidene)-4 H-1,2,4-triazol-4-amines. The procedure occurs by cleavage of the NN bond in the N-(alkylidene)-4 H-1,2,4-triazol-4-amines and activation of an aryl CH bond in the substituted pyridines. This is the first example of the preparation of imidazopyridine derivatives by using pyridines as the substrates by transition-metal-catalyzed CH functionalization. This method should provide a novel and efficient strategy for the synthesis of other nitrogen heterocycles. [ABSTRACT FROM AUTHOR]

Efficient copper-catalyzed aerobic oxidative CH and CC functionalization of 1-[2-(arylamino)aryl]ethanones leading to acridones has been developed. The procedure involves cleavage of aromatic CH and acetyl CC bonds with intramolecular formation of a diarylketone bond. The protocol uses inexpensive Cu(O2CCF3)2 as catalyst, pyridine as additive, and economical and environmentally friendly oxygen as the oxidant, and the corresponding acridones with various functional groups were obtained in moderate to good yields. [ABSTRACT FROM AUTHOR]