Mechanism of nitric acid oxidation of acetophenone to dibenzoylfurazan 2-oxide, benzoic acid, and benzoylformic acid

Abstract

Acetophenone, benzoylformaldehyde oxime, and benzoylnitromethane were oxidised with dilute nitric acid to dibenzoylfurazan 2-oxide, benzoic acid, and benzoylformic acid in aqueous organic solvents. The nitric acid oxidation of benzoylnitromethane in 78% aqueous nitromethane gave dibenzoylfurazan 2- oxide in ca. 70% yield, suggesting nitrosation of benzoylnitromethane to give nitrobenzoylformaldehyde oxime (benzoylformonitrolic acid). Similarly, acetophenone is considered to be attacked by the nitrosonium ion to give benzoylformaldehyde oxime, instead of benzoylnitromethane by nitration with nitrogen dioxide. Benzoylformic acid and benzoic acid are derived from the nitrolic acid and its oxidation product.