Selective methods for the synthesis of C(2)-monoallyl and C(2)-diallyl derivatives of lupane terpenoids were developed. The methods involve reactions of allyl halides with potassium enolates or potassium enoxy(triethyl)borates generated in situ from 3-oxolupanes (betulonic acid, 3-oxo betulin) under the action of KN(SiMe3)2, KH, or ButOK with subsequent addition of Et3B. The use of the reagent KN(SiMe3)2-Et3B in 1,2-dimethoxyethane ensured the kinetically controlled generation of enolate anions, which yielded 2β-propenyl lupane terpenoids with high stereoselectivity. Reactions of 3-oxolupanes with excesses of ButOK and allyl halide (2.5 equiv.) gave 2,2-bisallylation products. In vitro studies revealed that one of the latter efficiently suppresses the NO production by activated macrophages and has an antitumor effect on Ehrlich carcinoma and P-815 mastocytoma cell lines.
开发了合成
羽扇豆萜类化合物的 C(2)- 单烯丙基和 C(2)-
双烯丙基衍
生物的选择性方法。这些方法涉及在 KN(SiMe3)2、KH 或 ButOK 的作用下,烯丙基卤化物与 3-氧代
羽扇豆类化合物(
甜菜酸、3-氧代
甜菜碱)原位生成的烯醇酸
钾或烯氧(三乙基)
硼酸钾发生反应,随后加入 Et3B。在 1,2-
二甲氧基乙烷中使用试剂 KN(SiMe3)2-Et3B,可确保在动力学控制下生成烯醇阴离子,从而以高立体选择性生成 2β
丙烯基
羽扇豆萜类化合物。3-oxolupanes 与过量的 ButOK 和烯丙基卤化物(2.5 个等量物)反应生成 2,2-
双烯丙基化产物。体外研究显示,后者之一能有效抑制活化巨噬细胞产生的 NO,并对艾氏癌和 P-815 乳腺细胞瘤细胞株有抗肿瘤作用。