Nitric Acid → 3-Fluoro-4-nitropyridin-1-ium-1-olate

Temperature

120 °C

To a solution of 3-fluoropyridine N-oxide (3-2) (10.4 g, 90 mmol) in sulfuric acid (52 mL) stirring at 120° C. was added fuming nitric acid (21 mL) over 1 hour. After stirring at 120° C. for another 3 hours, the reaction mixture was cooled to ambient temperature and poured into 300 mL of ice. The pH of the solution was adjusted to pH 7 by addition of 20% sodium hydroxide, and extracted with chloroform. The organic layer was dried, filtered and concentrated. The residue was recrystallized from diethyl ether/hexane to give a pale yellow solid (7.5 g, 51%). 1H NMR (400 MHz, CDCl3): 8.05 (m, 2H), 8.22 (m, 1H)

1. temperaturethe reaction mixture was cooled to ambient temperature
2. extractionextracted with chloroform
3. customThe organic layer was dried
4. filtrationfiltered
5. concentrationconcentrated
6. customThe residue was recrystallized from diethyl ether/hexane

ORD record

ord-7de34b361d9a4b3fabc440e0a8ed83f1

Source dataset

uspto-grants-2004_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06777431B2