Water → 6,7-Dichloroquinoxaline-2,3-dione

Participants

Reaction Conditions

Reaction Steps

A suspension of 2.655 g (15.0 mmol) of 4,5-dichlorophenylene-1,2-diamine and 1.986 g (15.75 nmol) oxalic acid dihydrate (Fisher Scientific Co., used as received) in 22.5 mL of 2N aq. HCl was refluxed with stirring at 125° C. (bath temperature) for 2.5 h, (during the first 5 min heating, the suspension almost turned into a solution, then began to form a precipitate). The reaction mixture was allowed to cool to 22° C., and H2O (50 mL) was added. The precipitate was collected on a Hirsh funnel by vacuum filtration, washed with H2O (6×25 mL) and dried at 60° C. under 0.1 mmHg for 12 h affording 3.39 g (98%) of 6,7-dichloroquinoxaline-2,3-dione as a deep pink powder. Mp. >400° C. 1H NMR (DMSO-d6): δ12.016 (s, 2H), 7.234 (s, 2H). This product was used in the next reaction without further purification.

Provenance & Evidence