Oxidation and photochemical reactions of 3-phenyl-2H-1,4-benzoxazines

3-Phenyl-2H-1, 4-benzoxazines 4-oxides are light sensitive compounds, irradiation leads to 3-phenyl-2H-1,4-benoxazines and to their 3-oxidized derivatives, whenever possible. Intermediate oxaziridines are formed during the photolysis and transformed into stable nitroxide radicals. The structure of these radicals was confirmed through peracid oxidation of 3-phenyl-2H-1,4-benzoxazines and 3-phenyl-3, 4-dihydro-2H-1,4-benzoxazines. A reaction mechanism is proposed on the basis of experimental observations.