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

HRID 2229312Notes

Reaction equation

S(=O)(=O)(O)O.[F:6][C:7]1[CH:12]=[CH:11][CH:10]=[C:9]([F:13])[N:8]=1.[N+:14]([O-])([OH:16])=[O:15]>>[F:6][C:7]1[C:12]([N+:14]([O-:16])=[O:15])=[CH:11][CH:10]=[C:9]([F:13])[N:8]=1

Participants

Reactant 3

HCID 944Nitric Acid

HCID 1118Sulfuric Acid

HCID 739342,6-Difluoropyridine

Product 1

HCID 113895462,6-Difluoro-3-nitropyridine

Conditions

Temperature: 7.5 °C

Procedure

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).

Workup

extractionextracted with Et2O (2×2 L)
washThe combined organic layers were washed with aqueous 1.5 N NaOH (2×1 L)
dry with materialThe organic layers were dried over MgSO4
filtrationfiltrated
concentrationconcentrated under reduced pressure until constant weight (to remove unreacted 2,6-difluoropyridine: 10-12%)

Sources & evidence

ORD record: ord-18961df7d2854c1b9f45af2c315c6b63
Source dataset: uspto-grants-2002_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06420359B1

Reaction notes

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