Реакция #51524

Уравнение реакции

sodium cyanoborohydride

2′-O-allyl-3′,5′-bis(tert-butyl diphenylsilyl)guanosine

4-methyl morpholine-N-oxide

sodium bicarbonate

→

title compound

Выход 72.0%

2′-O-(2-hydroxyethyl)-3′,5′-bis(tert-butyldiphenylsilyl)guanosine

Выход 72.0%

Растворители

CH2Cl2

acetone

Условия реакции

Обработка

1. 1
   ДругоеReaction volume
2. 2
   Концентрированиеwas concentrated to half and ethyl acetate (50 mL)
3. 3
   workup.ADDITIONwas added
4. 4
   ПромывкаIt was then washed with water (30 mL) and brine (30 mL)
5. 5
   СушкаEthyl acetate layer was dried over anhydrous Na2SO4
6. 6
   Другоеevaporated to dryness
7. 7
   workup.DISSOLUTIONResidue was then dissolved in CH2Cl2
8. 8
   workup.ADDITIONwas added
9. 9
   workup.STIRRINGstirred with the reaction mixture for 30 min
10. 10
    ФильтрацияThe reaction mixture was filtered
11. 11
    Промывкаsilica was washed thoroughly with CH2Cl2
12. 12
    ДругоеCombined CH2Cl2 layer was evaporated to dryness
13. 13
    workup.DISSOLUTIONResidue was then dissolved
14. 14
    workup.DISSOLUTIONin dissolved in 1M pyridinium-p-toluene sulfonate (PPTS) in dry MeOH (99.5 mL) under inert atmosphere
15. 15
    workup.STIRRINGstirred at room temperature for 4 hr
16. 16
    Экстракцияextracted with ethyl acetate (2×50 mL)
17. 17
    СушкаEthyl acetate layer was dried over anhydrous Na2SO4
18. 18
    Другоеevaporated to dryness
19. 19
    Промывкаeluted with 10% MeOH in CH2Cl2

Методика

2′-O-allyl-3′,5′-bis(tert-butyl diphenylsilyl)guanosine (9 g, 11.23 mmol) was dissolved in CH2Cl2 (80 mL). To the clear solution acetone (50 mL), 4-methyl morpholine-N-oxide (1.89 g, 16.17 mmol) was added. The reaction flask was protected from light. Thus 4% aqueous solution of osmium tetroxide was added and the reaction mixture was stirred at room temperature for 6 hr. Reaction volume was concentrated to half and ethyl acetate (50 mL) was added. It was then washed with water (30 mL) and brine (30 mL). Ethyl acetate layer was dried over anhydrous Na2SO4 and evaporated to dryness. Residue was then dissolved in CH2Cl2 and NaIO4 adsorbed on silica (21.17 g, 2 g/mmol) was added and stirred with the reaction mixture for 30 min. The reaction mixture was filtered and silica was washed thoroughly with CH2Cl2. Combined CH2Cl2 layer was evaporated to dryness. Residue was then dissolved in dissolved in 1M pyridinium-p-toluene sulfonate (PPTS) in dry MeOH (99.5 mL) under inert atmosphere. To the clear solution sodium cyanoborohydride (1.14 g, 18.2 mmol) was added and stirred at room temperature for 4 hr. 5% aqueous sodium bicarbonate (50 mL) was added to the reaction mixture slowly and extracted with ethyl acetate (2×50 mL). Ethyl acetate layer was dried over anhydrous Na2SO4 and evaporated to dryness. Residue placed on a flash column and eluted with 10% MeOH in CH2Cl2 to givet the title compound (6.46 g, 72% yield). MS (Electrospray−) m/e 802 (M−H⊕)

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