反应详情

Compound 44a (9.0 g, 13.57 mmol) was coevaporated with anhydrous toluene (50 mL). To the residue N,N-tetraisopropylammonium tetrazolide (0.766 g, 6.8 mmol) was added and the mixture was dried over P2O5 in a vacuum oven for overnight at 40° C. The reaction mixture was dissolved in dichloromethane (20 mL) and 2-cyanoethyl-N,N,N′,N′-tetraisopropylphosphorodiamidite (6.13 g, 6.7 mL, 20.35 mmol) was added. The reaction mixture was stirred at ambient temperature for overnight. The completion of the reaction was ascertained by TLC(Rf=0.7 in 1:1 ethyl acetate:hexane). The reaction mixture was diluted with dichloromethane (100 mL) and washed with 5% NaHCO3 (100 mL) and brine (100 mL). The organic layer was dried over anhydrous Na2SO4 filtered and concentrated under reduced pressure. The residue was purified over silica gel (50:49:1, EtOAc:Hexane:triethlyamine) to afford compound 45a as white solid (10.5 g, 89%).

1. dry with materialthe mixture was dried over P2O5 in a vacuum oven for overnight at 40° C
2. dissolutionThe reaction mixture was dissolved in dichloromethane (20 mL)
3. washwashed with 5% NaHCO3 (100 mL) and brine (100 mL)
4. dry with materialThe organic layer was dried over anhydrous Na2SO4
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified over silica gel (50:49:1, EtOAc:Hexane:triethlyamine)