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

Concentrated H2SO4 (75 ml) was carefully added to 3-fluoropyridine N-oxide (Preparation 5) (50 g, 0.44 mol), cooled at room temperature by using a water bath. Fuming nitric acid (55 ml) was dissolved in concentrated sulfuric acid (75 ml) and the colourless solution was added drop-wise to the substrate over 15 minutes at room temperature. The yellow mixture was heated for 1.5 hours at 90° C. The mixture was allowed to reach room temperature and slowly poured onto ice (900 g). The aqueous layer was extracted with dichloromethane (3×500 ml) and the solvent evaporated under reduced pressure to yield a yellow solid. This was washed with pentane (200 ml). The residue was dissolved in dichloromethane (50 ml). A yellow precipitate formed which was filtered off to yield the title compound (10 g).

1. additionthe colourless solution was added drop-wise to the substrate over 15 minutes at room temperature
2. temperatureThe yellow mixture was heated for 1.5 hours at 90° C
3. customto reach room temperature
4. additionslowly poured onto ice (900 g)
5. extractionThe aqueous layer was extracted with dichloromethane (3×500 ml)
6. customthe solvent evaporated under reduced pressure
7. customto yield a yellow solid
8. washThis was washed with pentane (200 ml)
9. dissolutionThe residue was dissolved in dichloromethane (50 ml)
10. customA yellow precipitate formed which
11. filtrationwas filtered off

ORD 기록

ord-95dbcbc4f94b451d8262c350caf91d6f

출처 데이터셋

uspto-grants-2005_02

DOI

10.6084/m9.figshare.5104873.v1

특허 번호

US06855724B2