Colouring Matters of Australian Plants. XI. Quinones from Ventilago viminalis

Abstract

The root bark of Ventilago viminalis Hook. contains three new colouring matters now named ventimalin, viminalin, and ventilagone. The first of these has been identified as 1,3,4,5,6-pentahydroxy-2-methylanthraquinone and the structure has been confirmed by synthesis. Viminalin is shown to be the 4,5-dimethyl ether of ventimalin. Ventilagone is apparently a naphthoquinone of the hydroxy- juglone type. Two known anthraquinones, chrysophanol and islandicin, have also been isolated and there is evidence for the presence of helminthosporin.