methyl (4R)-4-[(5aS,7R,9aS,11aR,11S)-7-{[(4R)-4-[(5aS,7R,9aS,11aR,11S)-7,11-dihydroxy-9a,11a-dimethyl-4-oxohexadecahydro-1H-cyclopenta[1,2-a]phenanthren-1-yl]-1-oxopentyl]oxy}-11-hydroxy-9a,11a-dimethyl-4-oxohexadecahydro-1H-cyclopenta[1,2-a]phenanthren-1-yl]pentanoate