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

To a stirred solution of 19.5 g (97 mmol) of ethyl difluoro-2-pyridylacetate 4 in 200 mL of absolute ethanol at 0° C. was added 4.42 g (1 16 mmol) of sodium borohydride in small portions. After 30 min, the reaction was quenched by the addition of 50 mL of sat. NH4Cl. The reaction mixture was concentrated at reduced pressure and the residue partitioned between 500 mL of ethyl acetate and sat. NaHCO3. The organic layer was washed with water, brine, and dried over Na2SO4 and concentrated at reduced pressure to give a brown oil that was purified on SiO, (10×17 cm) using 1:1 EtOAc-hexane. After re-chromatographing the mixed fractions, all clean fractions were combined and concentrated at reduced pressure, giving 5 as a beige crystalline solid: 1H NMR (CDCl3) δ3.6 (t, 1H), 4.17-4.3 (m, 2H), 7.4-7.45 (m, 1H), 7.73 (d, 1H), 7.84-7.91 (m, 1H), 8.61 (d, 1H).

1. customthe reaction was quenched by the addition of 50 mL of sat. NH4Cl
2. concentrationThe reaction mixture was concentrated at reduced pressure
3. customthe residue partitioned between 500 mL of ethyl acetate and sat. NaHCO3
4. washThe organic layer was washed with water, brine
5. dry with materialdried over Na2SO4
6. concentrationconcentrated at reduced pressure
7. customto give a brown oil that
8. customwas purified on SiO, (10×17 cm)
9. concentrationconcentrated at reduced pressure

ORD record

ord-8180d63e57c4484aaed64f1123dca720

Source dataset

uspto-grants-2002_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06387911B1