反应详情

温度

-30 °C

Ethereal silver perchlorate (0.08 M, 76.9 mL, 6.15 mmol) is added with stirring at -30° C. to a solution of methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (2.078 g, 4.48 mmol), 4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl chloride (2.859 g, 5.6 mmol) and 2,4,6-trimethylpyridine (0.81 mL, 6.15 mmol) in ether (20 mL). The mixture is stirred 15 min at -30° C. and silver chloride precipitated. The mixture is filtered through a celite pad, the solids are washed with ether, the filtrate is concentrated under reduced pressure. The residue is dissolved in methylene chloride and the organic layer is washed successively with aqueous sodium thiosulfate and water. The organic layer is dried over sodium sulfate, filtered and concentrated under reduced pressure so as to afford a foam. Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate will afford methyl 6-O-(4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl)-2,3,4-tri-O-benzyl-α-D-glucopyranoside as a foam.

1. customsilver chloride precipitated
2. filtrationThe mixture is filtered through a celite pad
3. washthe solids are washed with ether
4. concentrationthe filtrate is concentrated under reduced pressure
5. dissolutionThe residue is dissolved in methylene chloride
6. washthe organic layer is washed successively with aqueous sodium thiosulfate and water
7. dry with materialThe organic layer is dried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated under reduced pressure so as
10. customto afford a foam
11. washFlash chromatography on silica gel and elution
12. additionwith a graded mixture of hexane and ethyl acetate