Hydrogen Peroxide → 2-Chloro-3-fluoropyridine N-oxide

Temperature

75 °C

A mixture of 2-chloro-3-fluoropyridine (11.8 g, 0.10 mol) and 11.4 ml of 30% hydrogen peroxide in acetic acid, 70 ml, is stirred at 75° C. for 4 hours. Additional 30% hydrogen peroxide, three 5 ml portions, is added over 24 hours followed by 3 ml of a saturated sodium bisulfite solution. The reaction mixture is concentrated to approximately 25 ml under reduced pressure at 55°-60° C., diluted with water, 30 ml, and made basic with potassium carbonate. The crude N-oxide is extracted into ethyl acetate, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. Chromatography over silica gel and elution with 2% MeOH- 98% CHCl3 (v/v) mixture gives 2-chloro-3-fluoropyridine N-oxide as a liquid.

1. concentrationThe reaction mixture is concentrated to approximately 25 ml under reduced pressure at 55°-60° C.
2. additiondiluted with water, 30 ml
3. extractionThe crude N-oxide is extracted into ethyl acetate
4. dry with materialdried over anhydrous magnesium sulfate
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. washChromatography over silica gel and elution with 2% MeOH- 98% CHCl3 (v/v) mixture

ORD record

ord-16b6d4b4f8bf4c22a20772027c4bf637

Source dataset

uspto-grants-1984_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04456604