2-Chloro-5-nitropyridine → 2-Fluoro-5-nitropyridine

Temperature

70 °C

To 100 g of 2-chloro-5-nitropyridine (Aldrich) in 600 mL of dimethyl sulfoxide under an inert atmosphere was added 100 g of anhydrous KF. The reaction was heated at 70° C. for 18 hours before cooling and diluting with 500 mL each of brine, ethyl acetate, and hexanes. This mixture was filtered through a pad of celite, the organic phase was separated, and the aqueous phase was extracted three times with equal volumes of ethyl acetate and hexanes. The pooled organic phases were washed with brine, dried with anhydrous sodium sulfate, and stripped of the solvents. This crude product was passed through a plug of silica gel with a gradient of 10-30% ethyl acetate/hexanes and stripped to constant weight on a rotary evaporator to give 76 g (84%) of 2-fluoro-5-nitropyridine as an oil, which was used in the following procedure.

1. temperaturebefore cooling
2. filtrationThis mixture was filtered through a pad of celite
3. customthe organic phase was separated
4. extractionthe aqueous phase was extracted three times with equal volumes of ethyl acetate and hexanes
5. washThe pooled organic phases were washed with brine
6. dry with materialdried with anhydrous sodium sulfate
7. customstripped to constant weight on a rotary evaporator

ORD record

ord-249cdb46c9ec46ec93a04ab666acb7d6

Source dataset

uspto-grants-2002_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06355636B1