反应详情

4,5-Dichloro-1-(2,3-di-O-acetyl-5-deoxy-beta-D-ribofuranosyl)-N-(1-methylethyl)-1H-benzimidazol-2-amine (0.82 g, 1.8 mmol) was dissolved in 1,4dioxane (Aldrich, 20 mL). Aqueous lithium hydroxide (5.5 mL, 1.0 M, 5.5 mmol) was added and the mixture was stirred for 30 min. The solution was then diluted with brine (50 mL) and extracted with ethyl acetate (3×50 mL). The organic layers were dried over magnesium sulfate, filtered, and evaporated. The crude residue was purified on a silica gel column (5×20 cm, 230-400 mesh) with 96:4 dichloromethane-methanol to give the title compound (0.48 g, 1.3 mmol, 72%); MS (AP+): m/z 360 (M+1); 1H NMR (DMSO-d6) δ: 7.11 (d, 1H, Ar—H, J=8.7 Hz), 7.04 (d, 1H, Ar—H, J=8.4 Hz), 6.75 (d, 1H, NH, J=7.5 Hz), 5.70 (d, 1H, H-1′, J=6.3 Hz), 5.27 (d, 1H, OH, J=6.6 Hz), 5.22 (d, 1H, OH, J=4.8 Hz), 4.28-4.35 (m, 1H, CH), 4.05-4.16 (m, 1H, CH), 3.77-3.92 (m, 2H, CH), 1.35 (d, 3H, 5′-CH3, J=6.6 Hz), 1.22 (d, 6H, CH3, J=6.6 Hz).

1. extractionextracted with ethyl acetate (3×50 mL)
2. dry with materialThe organic layers were dried over magnesium sulfate
3. filtrationfiltered
4. customevaporated
5. customThe crude residue was purified on a silica gel column (5×20 cm, 230-400 mesh) with 96:4 dichloromethane-methanol