2-O-[(3S,5R,8R,9S,10S,13R,14S,16S,17R)-16-acetyloxy-14-hydroxy-10,13-dimethyl-17-(6-oxopyran-3-yl)-1,2,3,4,5,6,7,8,9,11,12,15,16,17-tetradecahydrocyclopenta[a]phenanthren-3-yl] 1-O-benzyl oxalate