4-{2-[(1S,2R,10S,11S,14S,15S)-2,15-dimethyl-5-oxotetracyclo[8.7.0.02,7.011,15]heptadec-6-en-14-yl]-2-oxoethoxy}-4-oxobutanoic acid
4-{2-[(1S,3aS,3bS,9aR,9bS,11aS)-9a,11a-dimethyl-7-oxo-1H,2H,3H,3aH,3bH,4H,5H,7H,8H,9H,9aH,9bH,10H,11H,11aH-cyclopenta[a]phenanthren-1-yl]-2-oxoethoxy}-4-oxobutanoic acid