Phosphorus oxychloride → 2-Chloro-5-fluoro-3-nitropyridine

Temperature

80 °C

5-fluoro-3-nitro-pyridin-2-ol (2 g, 12.7 mmol) and benzyltrimethyl ammonium chloride (1.17 g, 6.35 mmol) were dissolved in acetonitrile, and phosphorus oxychloride (3.5 ml, 38.1 mmol) was added thereto and stirred at 80° C. for 6 hours. The reaction mixture was cooled and poured into ice water to quench the reaction, and extracted with dichloromethane. The combined organic layer was washed with saturated saline solution, dried over anhydrous sodium sulfate (Na2SO4), filtered and evaporated under reduced pressure. The residue was purified by column chromatography on silica eluting with a solvent of dichloromethane:methanol=30:1. The fractions containing the product were collected and evaporated to obtain yellow liquid (1.57 g, 70%).

1. temperatureThe reaction mixture was cooled
2. customto quench
3. customthe reaction
4. extractionextracted with dichloromethane
5. washThe combined organic layer was washed with saturated saline solution
6. dry with materialdried over anhydrous sodium sulfate (Na2SO4)
7. filtrationfiltered
8. customevaporated under reduced pressure
9. customThe residue was purified by column chromatography on silica eluting with a solvent of dichloromethane
10. additionThe fractions containing the product
11. customwere collected
12. customevaporated

ORD record

ord-0abad51d7529491d864ff7a7237f3854

Source dataset

uspto-grants-2013_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08394792B2