摘要:
Acetylation with acetic anhydride of (4alpha,8beta,13beta)-16-hydroxy-13-methyl-17-norkaurane-18-carboxylic acid and its methyl ester. obtained by reduction of isosteviol and (4alpha,8beta,13beta)-18-methoxycarbonyl-13-methyl-16-oxo-17-norkaurane, respectively, gives rise to (4alpha,8beta,13beta)-16-acetoxy-13-methyl-17-norkaurane-18-carboxylic acid and (4alpha,8beta.13beta)-16-acetoxy-18-methoxycarbonyl-13-methyl-17-norkaurane. The molecular and crystal structures of the compounds were established by X-ray diffraction.