Hydrochloric Acid → 2-Fluoro-4-hydroxybenzoic Acid

To a stirred solution of 2-fluoro-4-hydroxybenzonitrile (20.00 g, 145.9 mmol) in 160 mL of water, was added 50% aqueous sodium hydroxide (40.00 g, 500.0 mmol). The mixture was heated to reflux for 4 hours, cooled to room temperature, poured into iced concentrated hydrochloric acid, and extracted with ether. The product was extracted into saturated aqueous sodium bicarbonate and the ether layer discarded. This aqueous extract was acidified with concentrated hydrochloric acid and extracted with ether. The organic extract was dried over magnesium sulfate, filtered, and evaporated to give a white solid (22.90 g) of 2-fluoro-4-hydroxybenzoic acid in 100% yield, 1H NMR (300 MHz, CD3COCD3) δ (ppm): 9.80 (b, 1H), 7.87 (t, 1H), 6.77 (dd, 1H), 6.66 (dd, 1H). 19F-NMR (300 MHz, CD3COCD3) δ (ppm): −108.13 (s, decoupled). 2-Fluoro-4-hydroxybenzonitrile: 1H NMR (300 MHz, CD3COCD3) δ (ppm): 7.61 (t, 1H), 6.81 (m, 2H), 5.80 (b, 1H). 19F-NMR (300 MHz, CD3COCD3) δ (ppm): 108.82 (s, decoupled)

1. temperatureThe mixture was heated
2. temperatureto reflux for 4 hours
3. extractionextracted with ether
4. extractionThe product was extracted into saturated aqueous sodium bicarbonate
5. extractionThis aqueous extract
6. extractionextracted with ether
7. extractionThe organic extract
8. dry with materialwas dried over magnesium sulfate
9. filtrationfiltered
10. customevaporated

ORD record

ord-01d648d9f75a4433b6770144931110a8

Source dataset

uspto-grants-2016_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09255273B2