7α-(methoxycarbonyl)-15β,16β-methylene-3-oxo-17α-pregna-1,4-diene-21,17-carbolactone 生成 potassium;3-[(1R,2S,3S,5S,6S,7S,10S,11R,18R)-6-hydroxy-18-methoxycarbonyl-7,11-dimethyl-14-oxo-6-pentacyclo[8.8.0.02,7.03,5.011,16]octadeca-12,15-dienyl]propanoate