α-d-glucopyranoside with retained configuration were obtained. In the presence of polar solvents, the reaction afforded the epoxide product, suggesting the bicyclic oxiranium ion intermediate to be involved in this reaction. Compound 2 was eventually achieved by treating 4-methanesufonated glucopyranoside with fluoride ion and found to be a weak agonist for CD1d and NKT cell activation.
通过使用
DAST氟化α- d-
吡喃
葡萄糖苷的
4-羟基来合成潜在的免疫佐剂4-脱氧-4-
氟-KRN-7000(2)的尝试并未成功。取而代之的是,获得了具有保留构型的不寻常的5-脱氧-5-
氟β- 1-芦
呋喃糖苷和相应的4-脱氧-4-
氟α- d-
吡喃
葡萄糖苷。在极性溶剂存在下,该反应提供了
环氧化物产物,表明该反应涉及双环氧杂鎓离子中间体。化合物2最终通过用
氟离子处理4-
甲烷磺化的
吡喃
葡萄糖苷获得,并且发现它是CD1d和NKT细胞活化的弱激动剂。