methyl (4R)-4-[(4R,5aR,7R,9aS,11aR,11S)-7-{[(4R)-1-oxo-4-[(4R,5aS,7R,9aS,11aR,11S)-4,7,11-trihydroxy-9a,11a-dimethylhexadecahydro-1H-cyclopenta[1,2-a]phenanthren-1-yl]pentyl]oxy}-4,11-dihydroxy-9a,11a-dimethylhexadecahydro-1H-cyclopenta[1,2-a]phenanthren-1-yl]pentanoate