反应详情

To a solution of nucleoside 6 (2.79 g, 3.9 mmol) in anhydrous pyridine (50 cm3) was added a catalytic amount of 4-(N,N-dimethylamino)pyridine and p-toluenesulphonyl chloride (6.50 g, 34 mmol). The mixture was stirred in the dark for 24 h at room temperature under nitrogen. The reaction was quenched by addition of a saturated aqueous solution of sodium hydrogen carbonate (100 cm3) and the resulting mixture was extracted with dichloromethane. The combined organic phase was washed with saturated aqueous solutions of sodium hydrogen carbonate (3×75 cm3) and sodium chloride (2×75 cm3). The separated organic phase was dried (Na2SO4) and evaporated to dryness under reduced pressure. The residue was purified by silica gel column chromatography using dichloromethane/methanol/pyridine (0.5% methanol; 0.5% pyridine, v/v) as eluent to afford nucteoside 7 (2.40 g, 62%) as a yellowish foam after evaporation of the solvents. δC ((CD3)2SO) 163.2 (C-4), 158.2, 145.9, 145.1, 144.3, 136.8, 135.0, 134.9, 134.8, 131.8, 131.6, 130.2, 130.0, 129.7, 128.2, 127.9, 127.8, 127.6, 127.5, 127.5, 127.4, 126.8, 113.3 (DMT, C-6, 2×Ts, benzyl), 150.2 (C-2), 110.8 (C-5), 95.0, 86.2 (DMT, C-4′), 82.2, 81.9 (C-1′, C-2′), 81.2 (C-3′), 72.9 (CH2Ph), 79 (C-5″), 64 (C-5′), 55.1 (2×CH3O), 21.2, 21.2 (2×CH3), 12.0 (5-CH3).

1. customThe reaction was quenched by addition of a saturated aqueous solution of sodium hydrogen carbonate (100 cm3)
2. extractionthe resulting mixture was extracted with dichloromethane
3. washThe combined organic phase was washed with saturated aqueous solutions of sodium hydrogen carbonate (3×75 cm3) and sodium chloride (2×75 cm3)
4. dry with materialThe separated organic phase was dried (Na2SO4)
5. customevaporated to dryness under reduced pressure
6. customThe residue was purified by silica gel column chromatography