Persulphate oxidations. Part X. Heterocyclic synthesis by oxidation of ortho-substituted phenoxyacetic acids

Abstract

Photolysis of a series of N-(o-carboxymethoxybenzylidene)aniline N-oxides in the presence of persulphate yields the corresponding 4-aryl-2H-1,4-benzoxazin-3(4H)-ones as the principal products. Persulphate does not play an oxidative role in these reactions but is merely an indirect source of the protons which catalyse the rearrangement of the initial photoproduct, an oxaziridine.

Thermolytic and photolytic persulphate oxidation of o-formylphenoxyacetic acid gives mainly benzofuran-3-one; o-carboxyphenoxyacetic acid, its amide, and its anilide, give 1,3-benzodioxan-4-one.