Phosphorus oxychloride → 4-Chloro-6-isopropyl-3-nitro-1H-pyridin-2-one

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Reaction Steps

To a suspension of 4-hydroxy-6-isopropyl-3-nitro-1H-pyridin-2-one (3.02 g, 15.2 mmol) in CH3CN (60 mL) at room temperature is added benzyltriethylammonium chloride (13.88 g, 61.0 mmol). The mixture is stirred at room temperature for 5-10 min, and then POCl3 (6.25 mL, 67.1 mmol) is added. The reaction mixture is stirred at room temperature for 15 min and then at reflux for 1 h. After cooling, the reaction mixture is concentrated in vacuo. The flask is then placed in an ice bath, and the residue treated with H2O (˜60 mL). The mixture is stirred for 4 h while slowly warming to rt. The solid that forms over this period of time is collected by filtration and then washed with H2O and a small amount of hexanes. 4-Chloro-6-isopropyl-3-nitro-1H-pyridin-2-one is obtained as a yellow solid. 1H NMR (CDCl3, 300 MHz) δ 13.13 (br s, 1H), 6.24 (s, 1H), 2.89 (sept, J=6.9 Hz, 1H), 1.31 (d, J=6.9 Hz, 6H) ppm.

Provenance & Evidence