Reaktion #442525

Reaktionsgleichung

sodium tellurium hydride

tellurium

sodium borohydride

2'-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyloxy)-6'-hydroxyacetophenone

benzo[b]furan-5-carbaldehyde

potassium hydroxide

→

2'-(β-D-glucopyranosyloxy)-6'-hydroxy-3-(5-benzo[b]furanyl)propiophenone

Ausbeute 54.0%

Lösungsmittel

ethanol

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe mixture is evaporated
2. 2
   Sonstigeto remove the solvent
3. 3
   workup.ADDITIONto the residue are added water and diisopropyl ether
4. 4
   workup.STIRRINGThe mixture is stirred
5. 5
   Sonstigethe aqueous layer is collected
6. 6
   Temperaturcooling
7. 7
   Extraktionextracted with ethyl acetate
8. 8
   WaschenThe resulting organic layer is washed with water
9. 9
   Sonstigedried
10. 10
    Sonstigeevaporated
11. 11
    Sonstigeto remove the solvent
12. 12
    Sonstigeto give crude 2'-(β-D-glucopyranosyloxy)-6'-hydroxy-3-(5-benzo[b]furanyl)acrylophenone
13. 13
    Sonstigethe mixture is reacted at room temperature for 2.5 hours
14. 14
    SonstigeThe insoluble materials are removed by filtration
15. 15
    workup.ADDITIONto the filtrate are added water and ethyl acetate
16. 16
    workup.STIRRINGThe mixture is stirred
17. 17
    Sonstigethe organic layer is collected
18. 18
    Waschenwashed with water
19. 19
    Sonstigedried
20. 20
    Sonstigeevaporated
21. 21
    Sonstigeto remove the solvent
22. 22
    SonstigeThe residue is purified by silica gel column chromatography

Vorschrift

To a mixture of 2'-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyloxy)-6'-hydroxyacetophenone (965 mg), benzo[b]furan-5-carbaldehyde (350 mg) and ethanol (10 ml) is added dropwise a 50% aqueous potassium hydroxide solution (2 ml), and the mixture is stirred at room temperature overnight. The mixture is evaporated to remove the solvent, and to the residue are added water and diisopropyl ether. The mixture is stirred, and the aqueous layer is collected. The aqueous layer is neutralized with a 10% hydrochloric acid under ice-cooling, and extracted with ethyl acetate. The resulting organic layer is washed with water, dried, and evaporated to remove the solvent to give crude 2'-(β-D-glucopyranosyloxy)-6'-hydroxy-3-(5-benzo[b]furanyl)acrylophenone. This product is added to a solution of sodium tellurium hydride in ethanol (15 ml), which is previously prepared from tellurium (383 mg) and sodium borohydride (270 mg), and the mixture is reacted at room temperature for 2.5 hours. The insoluble materials are removed by filtration, and to the filtrate are added water and ethyl acetate. The mixture is stirred, and the organic layer is collected, washed with water, dried, and evaporated to remove the solvent. The residue is purified by silica gel column chromatography to give 2'-(β-D-glucopyranosyloxy)-6'-hydroxy-3-(5-benzo[b]furanyl)propiophenone (480 mg).

Quelle