目的 探索一种高效制备拟人参皂苷Rg₂、拟人参皂苷Rh₁和拟原人参三醇（PPT）的新方法，为制备拟人参皂苷和PPT提供理论依据。方法 依次以人参皂苷Re、人参皂苷Rh₁和PPT为原料，通过简单的3步反应（乙酰化反应、一步消去-加成反应、还原反应）进行制备，然后再利用色谱分离纯化，通过NMR、HR-ESI-MS、IR进行结构鉴定。结果 拟人参皂苷Rg₂（E/Z）、拟人参皂苷Rh₁（E/Z）和拟PPT（E/Z）产率分别是41%/13%、43%/11%、56%/15%。其中20（Z）-拟PPT为新化合物。结论 通过价格相对低廉且原料易得的人参皂苷Re、人参皂苷Rh₁和PPT制备出活性较好的拟人参皂苷Rg₂、拟人参皂苷Rh₁和拟PPT，为制备其他类型的拟人参皂苷提供了一种新的思路。同时此方法操作简单，产率较高。

Objective To explore an efficient preparation method of pseudo-ginsenoside Rg₂, pseudo-ginsenoside Rh₁, and pseudo-PPT, as to provide theoretical basis for the preparation of pseudo-ginsenosides and pseudo-PPT. Methods Ginsenosides Re, Rh₁, and PPT as raw material, via a simple three-step called acetylation, elimination-addition and saponification achieve the preparation of 20 (E/Z)-pseudo-ginsenoside Rg₂, 20 (E/Z)-pseudo-ginsenoside Rh₁, and 20 (E/Z)-pseudo-PPT. The detailed structure elucidation of the compounds were obtained by NMR, HR-ESI-MS, and IR. Results The production rates of 20 (E/Z)-pseudo-ginsenoside Rg₂, 20 (E/Z)-pseudo-ginsenoside Rh₁, and 20 (E/Z)-pseudo-PPT were 41%/13%, 43%/11%, and 56%/15%, respectively. Among them, 20 (Z)-pseudo-PPT was identified as new triterpenoid. Conclusion The method through the price relatively cheap and easy gain reactants ginsenoside Re, ginsenoside Rh₁, and PPT prepared active better pseudo-ginsenoside Rg₂, pseudo-ginsenoside Rh₁, and pseudo-PPT, the method for the preparation of other types of pseudo-ginsenoside provides a new train of thought. At the same time, the method is simple and the yield is high.