Glyoxylic Acid → 6,7-Dichloroquinoxalin-2(1H)-one

Participants

Reaction Steps

4,5-Dichloro-1,2-phenylenediamine (25 g, 141.2 mmol) was suspended in 780 ml EtOH, and 13 g (142.0 mmol) of glyoxylic acid (HO2CCOH/H2O) was added. The mixture was heated at reflux for 3 hours, and then cooled and filtered, yielding 27.45 g of 6,7-dichloroquinoxalin-2-one as a solid. The product (25 g, 116.3 mmol) and 230 ml (911.7 mmol) of phosphorous oxychloride (POCl3) were stirred at reflux (100° C.) for 3 hours. The mixture was cooled and ice/H2O added. The resulting brown/grey solid was filtered, and dried in an oven, yielding approximately 25 g of 2,6,7-trichloroquinoxaline.

Provenance & Evidence