Reaktion #51524

Reaktionsgleichung

sodium cyanoborohydride

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

4-methyl morpholine-N-oxide

sodium bicarbonate

→

title compound

Ausbeute 72.0%

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

Ausbeute 72.0%

Lösungsmittel

CH2Cl2

acetone

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeReaction volume
2. 2
   Einengenwas concentrated to half and ethyl acetate (50 mL)
3. 3
   workup.ADDITIONwas added
4. 4
   WaschenIt was then washed with water (30 mL) and brine (30 mL)
5. 5
   TrocknenEthyl acetate layer was dried over anhydrous Na2SO4
6. 6
   Sonstigeevaporated 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
    FiltrationThe reaction mixture was filtered
11. 11
    Waschensilica was washed thoroughly with CH2Cl2
12. 12
    SonstigeCombined 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
    Extraktionextracted with ethyl acetate (2×50 mL)
17. 17
    TrocknenEthyl acetate layer was dried over anhydrous Na2SO4
18. 18
    Sonstigeevaporated to dryness
19. 19
    Wascheneluted with 10% MeOH in CH2Cl2

Vorschrift

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⊕)

Quelle