Hydrochloric Acid → 8-Chloro-4-(4-methoxyphenyl)-3-oxoquinoxaline-2-carboxylic acid

Participants

Reaction Steps

7.7 g (21.5 mmol) of ethyl 5-chloro-1-(4-methoxyphenyl)-2-oxo-1,2-dihydroquinoxaline-3-carboxylate was dissolved in ethanol (100 ml), and 6.9 g (43.1 mmol) of a 25% aqueous solution of sodium hydroxide was added thereto. The mixture was stirred for 12 hours at room temperature. The reaction mixture was concentrated under reduced pressure, water was added to the residue thus obtained, and the mixture was acidified using 10% hydrochloric acid. A solid precipitated therefrom was separated by filtration, washed with water, and then dried, to obtain 6.7 g (yield: 94%) of 5-chloro-1-(4-methoxyphenyl)-2-oxo-1,2-dihydroquinoxaline-3-carboxylic acid as a pale yellow powder.

Provenance & Evidence