Quinones. Part VII. New routes to 2-hydroxy-1,4-naphthaquinones

Abstract

Both α- and β-tetralones can be converted into 2-hydroxy-1,4-naphthaquinones by autoxidation in the presence of potassium t-butoxide. 1,2-Dihydroxynaphthalenes, which are likely intermediates, are rapidly autoxidised under the same conditions to give the same products and the method can be used for converting 1,2-naphthaquinones into 2-hydroxy-1,4-naphthaquinones.Autoxidation of 5,7,8-trimethoxy-1-tetralone, followed by demethylation, gave 2,5,7,8-tetrahydroxy-1,4-naphthaquinone identical with mompain, a metabolite of Helicobasidium mompa Tanaka.