反应详情

温度

-30 °C

Thymidine (150 mg, 0.62 mmol) was co-evaporated with pyridine (2×5 ml, pro analysi quality, additionally dried over molecular sieve 4 Å), dissolved in pyridine and cooled to -30° C. A solution of 2-(4-chloro-2-nitrophenyl)ethoxycarbonyl chloride (255 mg, 0.97 mmol) in CH2Cl2 (3 ml, dist. over CaH2) was added dropwise thereto for 5 min. After being stirred for 4 h in conditions of i-PrOH/N2 cooling (-30° to -15° C.), the mixture was diluted with CH2Cl2 (30 ml) and washed with H2O (30 ml). The aqueous phase was post-extracted with CH2Cl2 (2×30 ml). The combined organic phases were dried over MgSO4, filtered and co-evaporated with toluene (4×10 ml) and CH2Cl2 (20 ml). The crude product was purified by column chromatography (SiO2 15×3 cm, solvent: CH2Cl2 /MeOH 100:7 700 ml). 5'-O-(2-(4-chloro-2-nitrophenyl)ethoxycarbonyl)thymidine (219 mg, 75% ) was obtained as a colorless solid.

1. customadditionally dried over molecular sieve 4 Å),
2. dissolutiondissolved in pyridine
3. washwashed with H2O (30 ml)
4. extractionThe aqueous phase was post-extracted with CH2Cl2 (2×30 ml)
5. dry with materialThe combined organic phases were dried over MgSO4
6. filtrationfiltered
7. customThe crude product was purified by column chromatography (SiO2 15×3 cm, solvent: CH2Cl2 /MeOH 100:7 700 ml)