Phosphorus oxychloride → 2-Chloro-6-methoxyquinoxaline

Participants

Reaction Steps

A mixture of 6-methoxyquinoxalin-2(1H)-one and 7-methoxyquinoxalin-2(1H)-one (5.67 g, 32.20 mmol) was refluxed in phosphorus oxychloride (120 mL) for 1 h. The reaction was concentrated and quenched by addition of ice, then basified with sodium carbonate, and extracted with ethyl acetate (3×200 mL). The organic layers were combined and concentrated in vacuo. The crude product was absorbed onto sodium sulfate and purified by column chromatography (0 to 5% ethyl acetate/hexanes) to afford 2-chloro-6-methoxyquinoxaline (2.21 g, 11.36 mmol, 35% yield). 1H NMR (400 MHz, CDCl3) δ ppm 8.69 (s, 1H), 7.88 (d, J=9.32 Hz, 1H), 7.43 (dd, J=9.32, 2.77 Hz, 1H), 7.37 (d, J=2.77 Hz, 1H), 3.95 (s, 3H).

Provenance & Evidence