Sodium borohydride → 2,2-Difluoro-2-(pyridin-2-YL)ethanol

Temperature

5 °C

Ethyl difluoro(pyridin-2-yl)acetate (G) obtained in step 1 (20 g) and 120 mL of ethanol were added, and 4 g of sodium borohydride was added to the reaction mixture over a period of 30 minutes at 0-5° C. The reaction mixture was stirred for 1 hour at 0-10° C. After completion of the reaction, the RM was quenched by adding saturated ammonium chloride solution at 0-5° C. and the volume of reaction mixture was reduced to half by distilling under vacuum. The solution was basified with 50% NaOH solution and extracted with MTBE. The organic layer was washed with a brine solution, dried over sodium sulphate and distilled under vacuum. The crude material was dissolved in 40 mL MTBE, 70 mL of n-hexane at 0-10° C. was added, and the RM was stirred for 30 minutes. The solid obtained was filtered and washed with hexane, resulting in pure product. (Yield=11 g).

1. customAfter completion of the reaction
2. customthe RM was quenched
3. additionby adding saturated ammonium chloride solution at 0-5° C.
4. customthe volume of reaction mixture
5. distillationby distilling under vacuum
6. extractionextracted with MTBE
7. washThe organic layer was washed with a brine solution
8. dry with materialdried over sodium sulphate
9. distillationdistilled under vacuum
10. dissolutionThe crude material was dissolved in 40 mL MTBE
11. addition70 mL of n-hexane at 0-10° C. was added
12. stirringthe RM was stirred for 30 minutes
13. customThe solid obtained
14. filtrationwas filtered
15. washwashed with hexane
16. customresulting in pure product

ORD record

ord-794d04e37e544a3693ded795a30aadb0

Source dataset

uspto-grants-2013_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08541580B2