反应详情

Mercuric cyanide (31.8 g, 126 mmol) and anhydrous calcium sulfate were added to a solution of 8-ethoxycarbonyl-1-octanol (25 g, 124 mmol) in 100 ml of dry benzene. The mixture was protected from moisture while stirring for 1 h at room temperature prior to addition of 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-α-D-glucopyranosyl chloride (25 g, 68 mmol). The mixture was efficiently stirred for 4 days at room temperature. Dichloromethane (400 ml) was added, the solids were removed by filtration, and the filtrate was sequentially washed with 10% aqueous sodium chloride solution (50 ml), once with saturated aqueous sodium bicarbonate solution (25 ml), and twice with water (50 ml). In each case, the aqueous layer was back-extracted with a little dichloromethane. After drying over magnesium sulfate, the solvents were removed to leave a syrup which crystallized from a mixture of diethyl ether and n-hexane. The crude yield of 8-ethoxycarbonyloctyl 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-D-glucopyranoside was 28.9 g (80%). A recrystallized sample showed mp 112°, [α]D20 -12.2° (c 2.4, chloroform). De-O-acetylation of this compound with triethylamine (27 ml) in methanol (500 ml) at 0°-5° for 18 h gave after evaporation of the solvent compound 2 as a chromatographically homogeneous powder which resisted crystallization and was therefore characterized as its hydrazide derivative mp 200°-201°, [α]D26 -22.5° (c 1, water), prepared by treating 2 with an 85% solution of hydrazine hydrate.

1. stirringThe mixture was efficiently stirred for 4 days at room temperature
2. customthe solids were removed by filtration
3. washthe filtrate was sequentially washed with 10% aqueous sodium chloride solution (50 ml), once with saturated aqueous sodium bicarbonate solution (25 ml)
4. extractionIn each case, the aqueous layer was back-extracted with a little dichloromethane
5. dry with materialAfter drying over magnesium sulfate
6. customthe solvents were removed
7. customto leave a syrup which
8. customcrystallized from a mixture of diethyl ether and n-hexane
9. customDe-O-acetylation of this compound with triethylamine (27 ml) in methanol (500 ml) at 0°-5° for 18 h gave
10. customafter evaporation of the solvent compound 2 as a chromatographically homogeneous powder which
11. customcrystallization
12. customprepared