反应详情

温度

5 °C

A saturated solution of HBr in CH2Cl2 (20.0 mL) was prepared by passing anhydrous HBr in CH2Cl2 at 0° C. for 30 min. This solution was added to a cold solution of the α-isomer of the 2,3,4-tri-O-benzylfucopyranose-p-nitrobenzoate (compound 8) (6.5 g, 11 mmol) in CH2Cl2 (150 mL) at 0-5° C., and the mixture was stirred at 5° C. for 30-40 min. The precipitated p-nitrobenzoic acid was filtered off, and the filtrate was successively washed with cold sat. NaHCO3 and water until neutral. The extract was dried (MgSO4) and the solvent removed at RT in vacuo to afford exclusively the α-fucopyranosyl bromide as a highly viscous liquid (5.3 g, yield 95%).

1. customat 0° C.
2. customfor 30 min
3. filtrationThe precipitated p-nitrobenzoic acid was filtered off
4. washthe filtrate was successively washed with cold sat. NaHCO3 and water until neutral
5. dry with materialThe extract was dried (MgSO4)
6. customthe solvent removed at RT in vacuo