Phosphorus oxychloride → 2-Chloro-5,6-dimethyl-3-nitropyridine

Participants

Reaction Steps

A mixture of 5,6-dimethyl-3-nitropyridin-2-ol (7.09 g, 42.2 mmol), benzyltriethylammonium chloride (4.82 g, 21.1 mmol) and acetonitrile (90 mL) at room temperature was slowly treated with phosphorus oxychloride (11.8 mL, 125 mmol) then heated to reflux and stirred overnight. The mixture was concentrated under reduced pressure and treated with ice-water (220 mL) and basified with concentrated ammonium hydroxide (100 mL). The mixture was extracted with dichloromethane (3×100 mL) and the combined extracts were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to yield 2-chloro-5,6-dimethyl-3-nitropyridine (7.28 g, 92%). Mp. 72-76° C.; 400 M Hz 1H NMR (CDCl3) δ: 8.01 (s, 1H), 2.58 (s, 3H), 2.38 (s, 3H).

Provenance & Evidence