Reaktion #51517

Reaktionsgleichung

NaHCO3

NaBH4

NH4Cl

1-[2′-O-(2-Ethylacetyl)-3′,5′-bis-O-(2,4-dichlorobenzyl)-β-D-ribofuranosyl]thymine

EtOH

NaBH4

→

title compound

Ausbeute 90.0%

1-[2′-O-(2-hydroxyethyl)-3′,5′-bis-O-(2,4-dichlorobenzyl)-β-D-ribofuranosyl]thymine

Ausbeute 90.0%

Lösungsmittel

CH2Cl2

CH2Cl2

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeover 10 minutes
2. 2
   workup.WAITleft
3. 3
   workup.WAITto stand for 8 hours
4. 4
   Sonstigeto give a gum
5. 5
   SonstigeThe solvent was decanted
6. 6
   Sonstigeevaporated in vacuo
7. 7
   Sonstigeto afford a white solid which
8. 8
   Extraktionthis solution was gently extracted with the CH2Cl2 containing the product
9. 9
   SonstigeThe organic layer was separated
10. 10
    Extraktionthe aqueous layer was extracted again with CH2Cl2 (2×50 mL)
11. 11
    Trocknenthe solvent was dried over MgSO4
12. 12
    Sonstigeevaporated in vacuo
13. 13
    Sonstigeto afford a white foam
14. 14
    Sonstigepurified by flash chromatography

Vorschrift

1-[2′-O-(2-Ethylacetyl)-3′,5′-bis-O-(2,4-dichlorobenzyl)-β-D-ribofuranosyl]thymine (9.92 g, 15.0 mmol) was dissolved in hot EtOH (150 mL) and the solution was cooled to ambient temperature in a water bath. To the solution was cautiously added NaBH4 (1.13 g, 30.0 mmol) over 10 minutes. After 3 hours additional NaBH4 (282 mg, 7.45 mmol) was added the mixture was stirred for 1 hour and left to stand for 8 hours. The pH was adjusted to 4 by addition of Saturated NH4Cl (25 mL) to give a gum. The solvent was decanted and evaporated in vacuo to afford a white solid which was dissolved in CH2Cl2 (250 mL). The gum was dissolved with saturated aqueous NaHCO3 and this solution was gently extracted with the CH2Cl2 containing the product. The organic layer was separated and the aqueous layer was extracted again with CH2Cl2 (2×50 mL). After combining the organic layers, the solvent was dried over MgSO4 and evaporated in vacuo to afford a white foam. The foam was dissolved in CH2Cl2 and purified by flash chromatography using hexanes-EtOAc, 20:80, to give the title compound as a white foam (8.39 g, 90%).

Quelle