Colouring matters of Australian plants. XX. Synthesis of hydroxyanigorufone and related phenalenones

Abstract

The structure of hydroxyanigorufone, one of the pigments of Anigozanthos rufus Labill., has been confirmed as 2-hydroxy-9-(4-hydroxyphenyl)phenalenone by synthesis. The general application of two synthetic methods, 9-arylation through addition of Grignard reagents and 2-hydroxylation through epoxidation, is demonstrated by the preparation of several other phenalenones related to natural products.