Sulfuric Acid → Methyl 3-chloro-2-oxo-1,2-dihydroquinoxaline-6-carboxylate

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Reaction Steps

Methyl 3-chloro-1-(4-methoxybenzyl)-2-oxo-1,2-dihydroquinoxaline-6-carboxylate (13 g, 36.31 mmol) was added to sulfuric acid (conc, 15 ml) in several batches with stirring at room temperature and then stirred an additional 10 mins. The resulting solution was quenched with ice-water (100 ml), adjusted to PH=7 with aqueous sodium hydroxide (10 N), and extracted with 1-butanol (3×200 ml). The organic layers were combined, dried over anhydrous magnesium sulfate, and concentrated in vacuo to afford methyl 3-chloro-2-oxo-1,2-dihydroquinoxaline-6-carboxylate as a yellow solid (12.4 g, crude).

Provenance & Evidence