齐墩果酸和熊果酸C3、C28衍生物的合成研究

目的设计合成齐墩果酸和熊果酸C_3、C_(28)衍生物。方法先将葡萄糖和半乳糖通过Schmidit法制备三氯乙酰亚胺酯糖给体;然后分别以齐墩果酸和熊果酸为起始原料,经苄基保护,再进行糖苷化、苄基脱保护、酰胺化、苯甲酰基脱保护,得到10个酰胺衍生物F_1~F_(10)。其中F_1、F_3通过四甲基哌啶氧化物(TEMPO)及NaClO/NaClO_2氧化体系得到糖醛酸化合物F_(11)、F_(12)。结果合成了5个熊果酸C_3位葡萄糖苷C_(28)位酰胺衍生物、5个齐墩果酸C_3位半乳糖苷C_(28)位酰胺衍生物及2个熊果酸C_3位葡萄糖醛酸苷C_(28)位酰胺衍生物,并分别通过1~H-NMR、(13)~C-NMR和MS确认结构。结论 12个化合物均未见报道,为三萜皂苷的构效关系及生物活性研究奠定基础。

Synthesis of oleanolic acid and ursolic acid C3 and C28 derivatives

Objective To design and synthesize the derivatives of oleanolic acid and ursolic acids C₃ and C₂₈. Methods First, glucose and galactose trichloroacetimidates donors were prepared with glucose and galactose by Schmidit method. Then oleanolic acid and ursolic acid were used as starting material to synthesize 10 target compounds F₁-F₁₀ by the benzyl protection, glycosylation, benzyl deprotection, amidation, and benzoyl deprotection. Iduronate compounds F₁₁ and F₁₂ were obtained from compounds F₁ and F₃ correspondingly via the TEMPO and NaClO/NaClO₂ oxidation system. Results Five 3-glucoside-28-amid triterpenoid saponins derivatives, five 3-galactoside- 28-amid triterpenoid saponins derivatives, and two 28-amid-3-O-glucuronic acid ursolic derivatives were obtained. All compounds were confirmed by the application of ¹H-NMR, ¹³C-NMR, and MS. Conclusion Twelve compounds are synthesized for the first time, which lays the foundation for the structure-function relationship and bioactivity studies of triterpenoid saponins.