Nitric Acid → 2,3,6-Trifluoro-5-nitropyridine

Participants

Reaction Conditions

Reaction Steps

To a 3-neck, round-bottomed flask was added 2,3,6-trifluoropyridine (25 g, 0.19 mol) followed by the addition of red fuming nitric acid (210 mL, 4.7 mol). Sulfuric acid (150 mL, 2.8 mol) was added to this mixture slowly via an addition funnel, maintaining internal temperature below 40° C. The resulting solution was heated to 60° C. for 30 minutes and allowed to cool to room temperature after heating. This solution was then further cooled in an ice-water bath and inversely quenched into a 2-L Erlenmeyer flask containing a mixture of ice and water (700 mL, 1:1 ratio). The quenched solution was then transferred to a 2-L separatory funnel and partitioned with hexanes (600 mL). The aqueous layer was subsequently washed with hexanes (600 mL) and methylene chloride (600 mL). The combined organic layers were then dried over Na2SO4, filtered, and concentrated to provide the title compound as a light yellow liquid (19.2 g, 57% yield).

Provenance & Evidence