methyl 3,3-ethylenedioxy-10-(2-propynyl)-17β-hydroxy-20-methoxy-19-norpregn-5-en-21-oate 生成 methyl (2Z)-2-methoxy-2-[(8'S,9'S,10'S,13'S,14'S)-13'-methyl-10'-prop-2-ynylspiro[1,3-dioxolane-2,3'-2,4,7,8,9,11,12,14,15,16-decahydro-1H-cyclopenta[a]phenanthrene]-17'-ylidene]acetate