Реакция #1695580

Уравнение реакции

ethyl 9,9-bis(4-fluorophenyl)-5-hydroxy-8-(5-phenyl-1H-tetrazol-1-yl)-3-oxo-6,8-nonadienoate

triethylborane

sodium borohydride

→

title compound

Выход 96.9%

Ethyl 9,9-bis(4-fluorophenyl)-3,5-dihydroxy-8-(5-phenyl-1H-tetrazol-1-yl)-6,8-nonadienoate

Выход 96.9%

Растворители

tetrahydrofuran

Условия реакции

Обработка

1. 1
   Температураthen cooled to -80° C. under argon
2. 2
   workup.STIRRINGthe suspension was stirred for one hour
3. 3
   ДругоеThe crude reaction
4. 4
   Другоеwas quenched with 4.0 mL of 2M HCl
5. 5
   ЭкстракцияThe mixture was extracted twice with ethyl acetate (40 mL)
6. 6
   Другоеevaporated
7. 7
   КонцентрированиеThe concentrated crude product
8. 8
   workup.ADDITIONwas diluted with 250 mL of methanol
9. 9
   workup.WAITto stand at room temperature for 45 minutes
10. 10
    Концентрированиеthen concentrated under reduced pressure at room temperature
11. 11
    ФильтрацияA solution of the crude product was filtered through silica gel
12. 12
    Концентрированиеthe filtrate was then concentrated under reduced pressure
13. 13
    ДругоеRecrystallization
14. 14
    workup.ADDITIONfrom a mixture of ethyl acetate-hexanes

Методика

A solution containing 0.9 g (1.7 mmoles) of ethyl 9,9-bis(4-fluorophenyl)-5-hydroxy-8-(5-phenyl-1H-tetrazol-1-yl)-3-oxo-6,8-nonadienoate in 20 mL of dry tetrahydrofuran at 0° C. under argon was treated with triethylborane (1.74 mL, 1.0M in THF, 1.74 mmoles). The colorless solution was allowed to stir at 0° C. for 1.5 hours then cooled to -80° C. under argon. To this stirring solution was added sodium borohydride (130 mg, 3.4 mmoles) in one portion and the suspension was stirred for one hour. The crude reaction was quenched with 4.0 mL of 2M HCl followed by 20 mL of half saturated aqueous NH4Cl solution. The mixture was extracted twice with ethyl acetate (40 mL) and the organic layers were combined and evaporated. The concentrated crude product was diluted with 250 mL of methanol and the solution was allowed to stand at room temperature for 45 minutes then concentrated under reduced pressure at room temperature. Analytical TLC showed only one spot for the product. A solution of the crude product was filtered through silica gel and the filtrate was then concentrated under reduced pressure. Recrystallization from a mixture of ethyl acetate-hexanes gave 0.9 g of the title compound; m.p.=160.5°-161.5° C.

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