1β,2β,3β,19α-tetrahydroxyurs-12-ene-28-oate-3-O-β-D-xylopyranoside 在
硫酸 作用下,
以
水 为溶剂,
以32 mg的产率得到(1R,2R,4aS,6aS,6bR,10R,11R,12S,12aR)-1,10,11,12-Tetrahydroxy-1,2,6a,6b,9,9,12a-heptamethyl-1,3,4,5,6,6a,6b,7,8,8a,9,10,11,12,12a,12b,13,14b-octadecahydro-2H-picene-4a-carboxylic acid