Sustainable Synthesis of 2-Arylbenzoxazoles over a Cobalt-Based Nanocomposite Catalyst

A new cobalt-based heterogeneous catalyst was prepared by adsorbing in situ produced nitrogen-ligated cobalt(II) acetate complexes on commercially available SiO2 and subsequent pyrolysis at 800 degrees C for 2 h under N-2 atmosphere. By applying this catalyst under the O-2 balloon, the aerobic oxidation of phenolic imines proceeded smoothly and gave various 2-arylbenzoxazoles in good yields. Meanwhile, on the basis of the experimental results, a plausible reaction pathway was described to elucidate the reaction mechanism