A new dinorxanthane and chromone from the root of Tithonia diversifolia

Diversifolide [4,15-dinor-3-hydroxy-1(5)-xanthen-12,8-olide], a novel dinor xanthane sesquiterpene, and a new chromone, 6-acetyl-7-hydroxy-2,3-dimethyl chromone, together with four known compounds, 2-deacetyl-11 beta,13-dihydro xyxanthinin, 2-acetyl-2,2-dimethylchromene, 6-acetyl-7-hydroxy-2,2-dimethyl chromene, and 6-acetyl-7-methoxy-2,2-dimethylchromene were isolated from th e root of Tithonia diversifolia. Their structures were spectroscopically de termined by 2D-NMR experiments, including heteronuclear multiple bond corre lation and nuclear Overhauser enhancement spectroscopy.