Chemistry of the Coccoidea. IX. Pigments from the lac insect Austrotachardia acaciae (Hemiptera) and associated synthetic work

Abstract

Minor pigments of the lacciferid Austrotachardia acaciae Maskell include isoerythrolaccin and the new 7-hydroxyerythrolaccin whose structure was confirmed by synthesis. Severe treatment of certain derivatives of 1,3-dihydroxyanthraquinone with aluminium chloride has resulted in novel deoxygenation to the 1-hydroxy series. The 1,2-dimethyl anthraquinones, 3,6,8-trihydroxy-1,2-dimethylanthraquinone and 3,6,7,8-tetrahydroxy-1,2-dimethylanthraquinone, have been synthesized. Oxidation of the methyl groups has been explored as a possible route to the synthesis of the major pigment from A. acaciae, xantholaccaic acid B.