Ammonia → 6,7-dichloro-N-hydroxy-1,4-dihydroquinoxaline-2,3-dione

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Reaction Steps

To a solution of 0.4 g (1.3 mmol) 4,5-dichloro-2-ethoxalylamino-1-nitrobenzene in 30 ml tetrahydrofuran was added 10 ml dimethylformamide and 0.4 ml 25% aqueous ammonia. The mixture was hydrogenated at atm. pressure by using 50 mg 5% Pd-C as a catalyst. The precipitate was filtered off and washed with tetrahydrofuran. The filter cake was washed several times with 5% aqueous potassium hydroxide. Acidification of the filtrate with 4N hydrochloric acid gave 0.14 g (45%) of 6,7-dichloro-1-hydroxyquinoxaline-2,3(1H,4H)-dione. M.p. decomp. 1H-NMR (DMSO-d6): 12.2 (2H, m), 7.50 (1H, s), 7.27 (1H, s). MS (m/e): 246 (M+, 35%).

Provenance & Evidence