反应详情

温度

50 °C

A mixture of 0,5 g (2,6 mmol) 5,6-diamino-2,3-dihydroxyquinoxaline and 20 ml water was added 0,6 ml (3,9 mmol) 40% aqueous glyoxal and 0,41 g (3,9 mmol) sodium carbonate. The reaction mixture was stirred at 50° C. for 1,5 h. After cooling to 25° C., the precipitate was filtered off and washed with water to give 0,49 g. The crude product was dissolved in 2N sodium hydroxide and reprecipitated with 2N hydrochloric acid to pH 6-7 to give 0,2 g (36%) 2,3-dihydroxypyrazino(2,3-f)quinoxaline, m.p.>300° C. NMR (DMSO-d6): 8.30 (1H,d), 8.20 (1H,d), 7.27 (1H,d), 7.0 (1H,d).

1. temperatureAfter cooling to 25° C.
2. filtrationthe precipitate was filtered off
3. washwashed with water
4. customto give 0,49 g
5. customreprecipitated with 2N hydrochloric acid to pH 6-7