反应详情

温度

-78 °C

To a solution of the compound of Preparation A (0.927 mmol), dissolved in 40 ml of dry tetrahydrofuran, there are added 2,3,4,6-tetra-O-acetylglucopyranose (1.95 mmol) and triphenylphosphine (1.95 mmol). The reaction mixture is cooled to −78° C., and then DEAD (1.95 mmol) is added dropwise. The temperature is slowly raised to ambient temperature, and the reaction mixture is then stirred for a further 15 hours. After hydrolysis, the organic product is extracted with ethyl acetate. The organic phases are combined, dried over magnesium sulphate and filtered, and the solvent is evaporated off. After purification by chromatography on silica gel (cyclohexane/ethyl acetate: 65/35, and then toluene/ethyl acetate 3/2), the β-glycosylated compound is obtained in the form of yellow crystals and the α-glycosylated compound is obtained in admixture with triphenylphosphine oxide.

1. customTo a solution of the compound of Preparation A (0.927 mmol)
2. temperatureThe temperature is slowly raised to ambient temperature
3. customAfter hydrolysis
4. extractionthe organic product is extracted with ethyl acetate
5. dry with materialdried over magnesium sulphate
6. filtrationfiltered
7. customthe solvent is evaporated off
8. customAfter purification by chromatography on silica gel (cyclohexane/ethyl acetate
9. custom65/35, and then toluene/ethyl acetate 3/2), the β-glycosylated compound is obtained in the form of yellow crystals