(((1S,3R,9S,10R,13S,14R)-17-((S)-1-(isopentyloxy)ethyl)-10,13-dimethyl-2,3,4,9,10,11,12,13,14,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthrene-1,3-diyl)bis(oxy))bis(tert-butyldimethylsilane)