Reacción #442525

Ecuación de reacción

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

Rendimiento 54.0%

Disolventes

ethanol

ethanol

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroThe mixture is evaporated
2. 2
   Otroto remove the solvent
3. 3
   workup.ADDITIONto the residue are added water and diisopropyl ether
4. 4
   workup.STIRRINGThe mixture is stirred
5. 5
   Otrothe aqueous layer is collected
6. 6
   Temperaturacooling
7. 7
   Extracciónextracted with ethyl acetate
8. 8
   LavadoThe resulting organic layer is washed with water
9. 9
   Otrodried
10. 10
    Otroevaporated
11. 11
    Otroto remove the solvent
12. 12
    Otroto give crude 2'-(β-D-glucopyranosyloxy)-6'-hydroxy-3-(5-benzo[b]furanyl)acrylophenone
13. 13
    Otrothe mixture is reacted at room temperature for 2.5 hours
14. 14
    OtroThe 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
    Otrothe organic layer is collected
18. 18
    Lavadowashed with water
19. 19
    Otrodried
20. 20
    Otroevaporated
21. 21
    Otroto remove the solvent
22. 22
    OtroThe residue is purified by silica gel column chromatography

Procedimiento

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).

Fuente