Efficient synthesis of substituted indoles and benzazoles by oxidative aromatization using activated carbon-molecular oxygen system

Efficient synthesis of substituted indoles was achieved by oxidative aromatization of indolines using activated carbon-molecular oxygen (O 2 ) system. Benzazoles (benzimidazole and benzothiazoles) were also prepared by the reaction of 1,2-phenylenediamine and 2-aminobenzenethiol with formaldehyde in the presence of activated carbon under oxygen atmosphere.