2α-methoxyursolic acid 在
吡啶 作用下,
以
甲醇 、
乙醚 为溶剂,
生成 (1S,2R,4aS,6aS,6bR,8aR,10R,11R,12aR,12bR,14bS)-10-Acetoxy-11-methoxy-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 methyl ester