반응 #51524

반응 방정식

sodium cyanoborohydride

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

4-methyl morpholine-N-oxide

sodium bicarbonate

→

title compound

수율 72.0%

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

수율 72.0%

용매

CH2Cl2

acetone

반응 조건

후처리

1. 1
   기타Reaction volume
2. 2
   농축was concentrated to half and ethyl acetate (50 mL)
3. 3
   workup.ADDITIONwas added
4. 4
   세척It was then washed with water (30 mL) and brine (30 mL)
5. 5
   건조Ethyl acetate layer was dried over anhydrous Na2SO4
6. 6
   기타evaporated 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
    여과The reaction mixture was filtered
11. 11
    세척silica was washed thoroughly with CH2Cl2
12. 12
    기타Combined 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
    추출extracted with ethyl acetate (2×50 mL)
17. 17
    건조Ethyl acetate layer was dried over anhydrous Na2SO4
18. 18
    기타evaporated to dryness
19. 19
    세척eluted with 10% MeOH in CH2Cl2

실험 절차

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⊕)

출처