Some halogenated derivatives of 2,6-dihydroxyanthracene

Abstract

Bromination of 2,6-dihydroxyanthracene in acetic acid occurs at the 1,5-positions. Its dimethyl ether, treated similarly, gives a mixture of 1,5- and 9,10-dibromo-derivatives, while its diacetate undergoes 9,10-disubstitution exclusively. 9,10-Dichlorination of the system is similarly effected. Under these conditions the use of 1 mol. of halogen leads to substitution at the 9-position only. The position of halogenation is readily determined by a combination of spectroscopic analysis and oxidation to anthraquinones. The latter process is brought about also by an excess of halogen.