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

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

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.

Herkunft & Nachweise