Colouring matters of the aphididae. Part XXIX. Partial synthesis of erythroaphin and related systems by oxidative coupling

Abstract

Mild ferricyanide oxidation of the glucoside B, derived by reduction of protoaphin-fb, leads to erythroaphin-fb, through its diglucoside, in an overall yield of 27%. This reaction is (less satisfactorily) effected by persulphate and by catalytic oxidation also. In the latter case, products of oxygenation are formed as well. The successful production of derivatives of 4,9-dihydroxyperylene-3,10-quinone by oxidative coupling of hydroxynaphthalenes depends not only on the positions of oxygen substituents but also on the degree of alkylation of the system.