Réaction #51524

Équation de réaction

sodium cyanoborohydride

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

4-methyl morpholine-N-oxide

sodium bicarbonate

→

title compound

Rendement 72.0%

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

Rendement 72.0%

Solvants

CH2Cl2

acetone

Conditions de réaction

Traitement

1. 1
   AutreReaction volume
2. 2
   Concentrationwas concentrated to half and ethyl acetate (50 mL)
3. 3
   workup.ADDITIONwas added
4. 4
   LavageIt was then washed with water (30 mL) and brine (30 mL)
5. 5
   SéchageEthyl acetate layer was dried over anhydrous Na2SO4
6. 6
   Autreevaporated 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
    Lavagesilica was washed thoroughly with CH2Cl2
12. 12
    AutreCombined 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
    Extractionextracted with ethyl acetate (2×50 mL)
17. 17
    SéchageEthyl acetate layer was dried over anhydrous Na2SO4
18. 18
    Autreevaporated to dryness
19. 19
    Lavageeluted with 10% MeOH in CH2Cl2

Mode opératoire

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⊕)

Source