Diethyl Oxalate → Pyrido(2,3-b)pyrazine-2,3-diol
Reaction equation
[NH2:1][C:2]1[C:7]([NH2:8])=[CH:6][CH:5]=[CH:4][N:3]=1.[C:9](OCC)(=[O:15])[C:10](OCC)=[O:11]>>[NH:8]1[C:10](=[O:11])[C:9](=[O:15])[NH:1][C:2]2[N:3]=[CH:4][CH:5]=[CH:6][C:7]1=2Participants
3
Conditions
- Temperature
- 120 °C
Procedure
A stirred suspension of 2,3-diaminopyridine (75 g, 687 mmol) in diethyl oxalate (291 ml, 2131 mmol) under N2 was heated to 120° C. After 1 h, the ethanol was distilled off the reaction mixture and the temperature was elevated to 160° C. for a further 2 hours. The reaction mixture was allowed to cool to RT and diluted with diethyl ether (200 ml). The resulting suspension was stirred for 1 hour and the solid was isolated by filtration and dried in a vacuum oven. The solid was suspended in ethanol (500 ml) and sonicated for 1 hour. The suspension was filtered and dried (vacuum oven overnight) to afford the titled compound;