反应 #2314353

反应方程式

sodium carbonate

diacetate

2-Bromo-5,6-dichloro-1-(2,3-di-O-acetyl-5deoxy-beta-D-ribofuranosyl)-1H-benzimidazole

→

title compound

收率 48.0%

2-Bromo-5,6-dichloro-1-(5-deoxy-beta-D-ribofuranosyl)-1H-benzimidazole

收率 48.0%

溶剂

water

ethanol

methanol

—

hexanes

反应条件

后处理

1. 1
   浓缩The reaction mixture was concentrated
2. 2
   workup.DISSOLUTIONdissolved in ethyl acetate (125 mL)
3. 3
   萃取extracted with water (3×50 mL)
4. 4
   干燥The ethyl acetate layer was dried with magnesium sulfate (anhyd)
5. 5
   过滤filtered
6. 6
   其他evaporated
7. 7
   其他The crude residue was purified on a silica gel column with 1:30 methanol
8. 8
   其他The resulting product was further purified on a silica gel column with 1:2 ethyl acetate

实验过程

2-Bromo-5,6-dichloro-1-(2,3-di-O-acetyl-5deoxy-beta-D-ribofuranosyl)-1H-benzimidazole (7.70 g, 16.52 mmol) was dissolved in ethanol (100 mL) and methanol (100 mL). A solution of sodium carbonate (1.75 g, 16.52 mmol) in water (30 mL) was added to the diacetate solution. The resulting mixture was stirred at rt for 17 h. The reaction mixture was concentrated, dissolved in ethyl acetate (125 mL) and extracted with water (3×50 mL). The ethyl acetate layer was dried with magnesium sulfate (anhyd), filtered, and evaporated. The crude residue was purified on a silica gel column with 1:30 methanol:CH—2Cl2. The resulting product was further purified on a silica gel column with 1:2 ethyl acetate: hexanes, followed by 1:1 ethyl acetate:hexanes to give the title compound (3.00 g, 7.85 mmol, 48%); MS (El): m/z (rel. intensity) 405 (0.05, M++Na); 1H NMR (DMSO-d6) δ8.00 (s, 1H, Ar—H), 7.87 (s, 1H, Ar—H), 5.87 (d, 1H, OH, J=6.7 Hz), 5.53 (d, 1H, OH, J=6.2 Hz), 5.29 (d, 1H, CH, J=5.1 Hz), 4.52 (m, 1H, CH), 4.01 (m, 1H, CH), 3.91 (m, 1H, CH), 1.42 (d, 3H, CH3, J=6.5 Hz).

来源