Reaktion #710491

Reaktionsgleichung

water

sodium borohydride

ethyl (3,5-dichloropyridin-2-yl)(difluoro)acetate

HCl

→

2-(3,5-dichloropyridin-2-yl)-2,2-difluoroethanol

Lösungsmittel

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   ExtraktionThe aequeous phase was extracted three times by 300 mL of ethyl acetate
2. 2
   Waschenthe organic phase was successively washed with brine, water
3. 3
   Trocknendried over magnesium sulfate
4. 4
   SonstigeAfter evaporation of the solvent under vacuum 8.5 g of yellow oil
5. 5
   Sonstigewere obtained
6. 6
   FiltrationAfter trituration in diisopropyl ether and filtration 6.8 g (80%) of 2-(3,5-dichloropyridin-2-yl)-2,2-difluoroethanol (Int-9)
7. 7
   Sonstigewere obtained as a white solid
8. 8
   SonstigeMp (melting point)=56° C. (M+1)=228

Vorschrift

To a solution of 10 g (37 mmol) of ethyl (3,5-dichloropyridin-2-yl)(difluoro)acetate (Int-7) in 60 mL of ethanol, were added portionwise at 0° C., 1.05 g (27.7 mmol) of sodium borohydride. The reaction mixture was stirred below 10° C. for 2 hours. 30 mL of 1 N HCl were then slowly added followed by 500 mL of water. The aequeous phase was extracted three times by 300 mL of ethyl acetate and the organic phase was successively washed with brine, water and dried over magnesium sulfate. After evaporation of the solvent under vacuum 8.5 g of yellow oil were obtained. After trituration in diisopropyl ether and filtration 6.8 g (80%) of 2-(3,5-dichloropyridin-2-yl)-2,2-difluoroethanol (Int-9) were obtained as a white solid. Mp (melting point)=56° C. (M+1)=228. 19F-NMR (235 MHz, CDCl3) δ (ppm): −105.85 (CF2).

Quelle