Three related diterpenoid quinones, royleanone, 9-acetoxyroyleanone, and 9- dehydroroyleanone, have been isolated from the roots of Inula royleana DC These have been assigned structures on the basis of degradation studies and the synthesis of royleanone from ferruginol.
![[(4aS)-8-hydroxy-1,1,4a-trimethyl-5,6-dioxo-7-propan-2-yl-2,3,4,9,10,10a-hexahydrophenanthren-9-yl] acetate结构式](https://image.chemsrc.com/caspic/217/6812-88-0.png)
