反应详情

温度

60 °C

To a stirred suspension of the anomeric mixture 3 (7.26 g, 0.013 mol) and thymine (3.25 g, 0.028 mol) in anhydrous acetonitrile (80 cm3) was added N,O-bis(trimethylsilyl)acetamide (19.1 cm3, 0.077 mol). The reaction mixture was stirred at 60° C. for 1 h and then cooled to 0° C. Trimethylsilyl triflate (4.1 cm3, 0.023 mol) was added drop-wise during 10 min and the mixture was subsequently heated for 22 h under reflux. After cooling to room temperature, a saturated aqueous solution of sodium hydrogen carbonate (30 cm3) was added and extraction was performed using dichloromethane (100 cm3×3). The combined organic phase was washed with saturated aqueous solutions of sodium hydrogen carbonate (30 cm3×3) and brine (50 cm3×3), dried (Na2SO4) and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using dichloromethane/methanol (0.5–2.0% methanol, v/v) as eluent to give nucleoside 4 (6.88 g, 85%) as a white solid material after evaporation of the solvents under reduced pressure. δH (CDCl3) 8.97 (1H, br s), 8.04–7.23 (16H, m), 6.37 (1H, d, J 3.6), 5.42 (1H, t, J 3.1), 4.89–4.56 (6H, m), 4.22 (1H, d, J 2.6), 2.13 (3H, s), 1.74 (1H, d, J 0.8) δC (CDCl3) 169.9, 166.0, 165.7, 163.4, 150.4, 136.2, 135.2, 133.5, 133.4, 129.8, 129.7, 129.6, 129.5, 129.0, 128.6, 128.4, 128.2, 112.0, 87.4, 86.0, 81.3, 80.3, 72.6, 63.1, 82.9, 20.8, 12.3. FAB-MS m/z 629 [M+H]+. Found (%) C, 64.4; H, 4.9; N, 4.4; C34H32N2O10,0.25H2O requires C, 64.5; H, 5.1; N, 4.4.

1. temperaturecooled to 0° C
2. temperaturethe mixture was subsequently heated for 22 h
3. temperatureunder reflux
4. temperatureAfter cooling to room temperature
5. extractionextraction
6. washThe combined organic phase was washed with saturated aqueous solutions of sodium hydrogen carbonate (30 cm3×3) and brine (50 cm3×3)
7. dry with materialdried (Na2SO4)
8. concentrationconcentrated under reduced pressure
9. customThe residue was purified by silica gel column chromatography