Studies in the biochemistry of micro-organisms. 109. The structure of asperthecin

Abstract

Several new derivatives of asperthecin have been prepared. Acetylation of asperthecin with acetic anhydride has given the triacetate, m.p. 248-250[degree] (decomp.), and the tetra-acetate, m.p. 251-253[degree] (decomp.). Asperthecic acid has been obtained by the oxidation (nitrous acid in concentrated sulphuric acid) of the hydroxymethyl group of asperthecin to a carboxyl group. Asperthecic acid has been decarboxylated to a pentahydroxyanthraquinone. The condensation of hemipinic anhydride with 1,2,4-trimethoxybenzene has given 2-(2''-hydroxy-4'' ,5'' -dimethoxybenzoyl) -3,4-dimethoxybenzoic acid. Subsequent ring closure and demethylation of the benzoylbenzoic acid has afforded 3,4,5,7,8-pentahydrozanthraquinone, identical with decarboxyasperthecic acid. Asperthecin is, therefore, represented by the structure 3,4,5,7,8-pentahydroxy-2-hydroxymethyl-anthraquinone.