反应详情

温度

25 °C

A mixture of 0,5 g (2,6 mmol) 5,6-diamino-2,3-dihydroxyquinoxaline and 10 ml water was at 50° C. added a solution of 0,45 g (5,2 mmol) 2,3-butanedione in 5 ml water. The reaction mixture was stirred at 50° for 4 h. After cooling to 25° C., the precipitate was filtered off and washed with water. The crude product was dissolved in 2N sodium hydroxide and reprecipitated with 2N hydrochloric acid to pH 6-7 to give 0,4 g (64%) 2,3-dihydroxy-8,9-dimethylpyrazino(2,3-f)quinoxaline, m.p.>300° C. NMR (DMSO-d6): 7.27 (1H,d), 6.93 (1H,d), 2.07 (6H,s).

1. customwas at 50° C.
2. filtrationthe precipitate was filtered off
3. washwashed with water
4. dissolutionThe crude product was dissolved in 2N sodium hydroxide
5. customreprecipitated with 2N hydrochloric acid to pH 6-7