Biphenylenes. Part XXIV. Synthesis of 6,7-dihydroxybiphenylene-2,3-quinone and its 1,8-dimethyl derivative (dibenzologues of squaric acid)

Abstract

6,7-Dihydroxybiphenylene-2,3-quinone has been made by the demethylation of its 6,7-dimethyl ether. 6,7-Dihydroxy-1,8-dimethylbiphenylene-2,3-quinone has been made by demethylation followed by aerial oxidation of 2,3,6,7-tetramethoxy-1,8-dimethylbiphenylene, and by the alkaline hydrolysis of 6,7-diacetoxy-1,8-dimethylbiphenylene-2,3-quinone. The properties of these two dibenzologues of squaric acid are discussed.