Nitric Acid → 2,6-Difluoro-3-nitropyridine

Participants

Reaction Conditions

Reaction Steps

To a mixture of concentrated sulphuric acid (600 mL) and fuming nitric acid (90%, 400 mL) in a ice-bath (internal temperature maintained at 5-10° C.) was added drop-wise 2,6-difluoropyridine (200 g, 1.74 mol). The resulting mixture was stirred overnight at room temperature. The mixture was poured slowly into 3 kg of ice and extracted with Et2O (2×2 L). The combined organic layers were washed with aqueous 1.5 N NaOH (2×1 L), then with aqueous saturated NaHCO3 (400 mL) or until pH is around 8-9. The organic layers were dried over MgSO4, filtrated and concentrated under reduced pressure until constant weight (to remove unreacted 2,6-difluoropyridine: 10-12%). The title compound was obtained as a yellow liquid (207.3 g, 74% yield).

Provenance & Evidence