Syntheses of Damnacanthal, Damnacanthol, Norjuzunal, and Norjuzunol, the Coloring Matters of Damnacanthus Spp

Abstract

Syntheses of damnacanthal, damnacanthol, norjuzunal and norjuzunol, the coloring matters of Damnacanthus spp. were described. The structures of juzunal and juzunol were synthetically established respectively as 2-formyl-and 2-hydroxymethyl-1-methoxy-3, 5-dihydroxyanthraquinone. These pigments are the first example of 1, 3, 5-trihydroxyanthraquinones occurring in nature.