(3S,7S,8S,9S,10R,11R,13S,14S,17R)-7-(methoxycarbonyl)-10,13-dimethyl-5'-oxo-1,2,3,4,4',5',7,8,9,10,11,12,13,14,15,16-hexadecahydro-3'H-spiro[cyclopenta[a]phenanthrene-17,2'-furan]-3,11-diyl diacetate