Phosphorus oxychloride → 3-Chloroquinoxaline-6-carbonitrile

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Reaction Steps

A solution of 3-oxo-3,4-dihydro-quinoxaline-6-carbonitrile (5.99 g, 35 mmol, 1.0 eq) in phosphorus oxychloride (26 mL, 280 mmol, 8.0 eq) is heated under reflux for 1 hour. Then the reaction mixture is cooled down to room temperature and the solvent is evaporated. The residue is poured into ice water, the resulting mixture is neutralized with sodium carbonate and extracted with ethyl acetate (3×50 mL). The combined organic layers are dried over sodium sulfate, filtered and concentrated to give a crude product that is purified by column chromatography (silica gel, eluent: dichloromethane 100%) to afford 3-chloro-quinoxaline-6-carbonitrile as a white solid (5.27 g, 79% yield).

Provenance & Evidence