Catalytic Oxidation of para-Substituted Phenols with Nitrogen Dioxide and Oxygen.

Abstract A series of para-substituted phenols was oxidized to the corresponding benzoquinones in moderate to high yield with catalytic amounts of NO2 under O2 in MeOH. Little or no oxidation is observed under argon. Substrates of lower reactivity gave quinones when treated with stoichiometric amounts of NO2 in CCl4, but nitration of the aromatic ring became a significant side product.