Colouring Matters of Australian Plants. XXI. Naphthoxanthenones in the Haemodoraceae

Abstract

Two new pigments, haemofluorone A and haemofluorone B, have been isolated from the flowers of Macropidia fuliginosa Drum. and also from the root system of Phlebocarya ciliata R.Br. Spectroscopic analysis indicates the structures 5,8,9- and 8,9,11-trihydroxy-lH-naphtho[2,1,8-mna]xanthen-l-one. The former structure has been confirmed by a synthesis of the trimethyl ether by photochemical oxidative cyclization of 9-(3,4-dimethoxyphenyl)-6-hydroxy-2-methoxy-1H-phenalen-1-one.The parent chromophore, 1H-naphtho[2,1,8-mnalxanthen-1-one, and the 2,5-dimethoxy derivative have also been prepared by analogous photochemical reactions of the appropriate arylphenalenones.