重氮甲烷 、
2α,3α,19α,23-tetrahydroxyurs-12-ene-24,28-dioic acid 以
乙醚 为溶剂,
以14 mg的产率得到(2R,3R,4R,4aR,6aR,6bS,8aS,11R,12R,12aS,14aR,14bR)-2,3,12-Trihydroxy-4-hydroxymethyl-6a,6b,11,12,14b-pentamethyl-2,3,4,4a,5,6,6a,6b,7,8,9,10,11,12,12a,14,14a,14b-octadecahydro-1H-picene-4,8a-dicarboxylic acid dimethyl ester