丙酸酐 、 Acetic acid 2-(1-acetoxy-ethyl)-5-[(3S,5S,8R,9S,10R,13S,14S)-10,13-dimethyl-6,16-dioxo-3-((2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-hydroxymethyl-tetrahydro-pyran-2-yloxy)-hexadecahydro-cyclopenta[a]phenanthren-17-yl]-5-hydroxy-1,1-dimethyl-hexyl ester 在
吡啶 作用下,
生成