反应详情

402 mg (0.7 mmol) of 5'-O-trityl-N-benzoyl-2'-deoxycytidine [prepared as described in step (a) above] were dried by azeotropic distillation with pyridine and then dissolved in 3.5 ml of methylene chloride. 60 mg (0.35 mmol) of diisopropylammonium tetrazolide were added to the solution. 245 μl (0.77 mmol) of 2-cyanoethyl N,N,N',N'-tetraisopropylphosphorodiamidite were then added dropwise, under an atmosphere of argon. The resulting mixture was stirred at room temperature for 3.5 hours under same atmosphere. At the end of this time, the methylene chloride was removed by distillation under reduced pressure. The resulting residue was dissolved in ethyl acetate, and the solution was washed with a 10% w/v aqueous solution of sodium carbonate and with a saturated aqueous solution of sodium chloride, in that order. The solution was then dried over anhydrous magnesium sulfate, after which the solvent was removed by distillation under reduced pressure, and the residue was purified by column chromatography through 23 g of silica gel (70-230 mesh), using ethyl acetate as the eluent, to give 337 mg (yield 62%) of the title compound as a foam substance.

1. customAt the end of this time, the methylene chloride was removed by distillation under reduced pressure
2. dissolutionThe resulting residue was dissolved in ethyl acetate
3. washthe solution was washed with a 10% w/v aqueous solution of sodium carbonate and with a saturated aqueous solution of sodium chloride, in that order
4. dry with materialThe solution was then dried over anhydrous magnesium sulfate
5. customafter which the solvent was removed by distillation under reduced pressure
6. customthe residue was purified by column chromatography through 23 g of silica gel (70-230 mesh)