中文摘要：

选择性去甲基反应在天然产物的修饰、转化和合成中有重要的意义。以珠子草中分离提纯的木脂素Phyllanthin为原料，采用AlCl3／（CH3）2S／CH2Cl2体系在0℃条件下对其进行O-选择性去甲基化反应，得到目标产物，并利用FT-IR、^1H-NMR和^13C-NMR对其化学结构进行表征。结果表明，Phyllanthin在C-9a的位置上发生了选择性去甲基化反应。

英文摘要：

The selective demethylation, reaction has great significance for the modification, conversion and synthesis of natural products. O-demethylation of lignan phyllanthin, obtained from phillanthus niruri, was carried out under AlCl4（ CH3 ）2S/ CH2Cl2 system in 0℃. This reaction led a methyl group in aliphatic methyl ether moiety to be removed selectively to form an alcohol moiety. The structure of the product was elucidated by FT-IR,^1H-NMR and ^13C-NMR. It showed that phyllanthin was C-9a demethvlated.