反应详情

温度

-60 °C

N4 -(2-(4-nitrophenyl)ethoxycarbonyl)-2'-deoxycytidine (5 g, 11.9 mmol) was co-evaporated with pyridine (2×60 ml, pro analysi quality, additionally dried over molecular sieve 4 Å), dissolved in pyridine (60 ml, see above) and cooled to -60° C. (i-PrOH/N2). A solution of 2-(2-chloro-6-nitrophenyl)ethoxycarbonyl chloride (4.7 g, 17.8 mmol) in CH2Cl2 (60 ml, dist. over CaH2) was added dropwise thereto for 75 min and was stirred for 1 h 45 min in conditions of i-PrOH/N2 cooling (-40° to -25° C.). The mixture was diluted with CH2Cl2 (150 ml) and washed with H2O (100 ml). The aqueous phases were post-extracted with CH2Cl2 (100 ml). Drying the organic phases over Na2SO4, filtering, evaporating the solvent under reduced pressure and co-evaporating with toluene (3×50 ml) yielded the crude product (9.8 g) which was purified by column chromatography (440 g SiO2, 32×5.9 cm, solvent: CH2Cl2 /MeOH 100:4). 5'-O-(2-(2-chloro-6-nitrophenyl)ethoxycarbonyl)-N4 -(2-(4-nitrophenyl)ethoxycarbonyl)-2'-deoxycytidine (5.247 g, 680%) was obtained as a colourless foam.

1. customadditionally dried over molecular sieve 4 Å),
2. dissolutiondissolved in pyridine (60 ml, see above)
3. washwashed with H2O (100 ml)
4. extractionThe aqueous phases were post-extracted with CH2Cl2 (100 ml)
5. dry with materialDrying the organic phases over Na2SO4
6. filtrationfiltering
7. customevaporating the solvent under reduced pressure and co-evaporating with toluene (3×50 ml)
8. customyielded the crude product (9.8 g) which
9. customwas purified by column chromatography (440 g SiO2, 32×5.9 cm, solvent: CH2Cl2 /MeOH 100:4)