Chemical constituents of Eriococcus confusus Maskell. I. The quinonoid pigments

Abstract

Eriococcus confusus Maskell., growing on both Eucalyptus caesia and maculosa, contains a number of anthraquinone pigments. Emodin has been identified as one of the major components, and the other is tentatively assigned the structure 1,2,3,8-tetrahydroxy-6-methylanthrquinone. Chromatographic and p.m.r, data are presented for a number of anthraquinones, including the new compounds 1,3,5-trihydroxy-6- methylanthraquinone and 1,3,5-trihydroxy-7-methylanthraquinone. In addition to the pigments, the insects are covered with a waxy secretion, which probably consists of a mixture of long-chain, saturated ketones in the C₂₀-C₂₄ range.