反应详情

温度

-30 °C

Ethereal silver perchlorate (0.08M, 76.9 mL, 6.15 mmol) was 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 was stirred 15 min at -30° C. and silver chloride precipitated. The mixture was filtered through a celite pad, the solids were washed with ether, the filtrate was concentrated under reduced pressure. The residue was dissolved in methylene chloride and the organic layer was washed successively with aqueous sodium thiosulfate and water. The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure to afford a foam. Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate afforded methyl 6-O-(4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl) -2,3,4-tri-O-benzyl-α-D-glucopyranoside (2.314 g, 55%) as a foam.

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