Potassium cyanate → N-[4-(5-Oxo-4,5-dihydropyrazin-2-yl)phenyl]urea

Reaction equation

Cl.[NH2:2][C:3]1[CH:8]=[CH:7][C:6]([C:9]2[N:10]=[CH:11][C:12](=[O:15])[NH:13][CH:14]=2)=[CH:5][CH:4]=1.[O-:16][C:17]#[N:18].[K+]>O.CN(C)C1C=CN=CC=1>[NH:2]([C:3]1[CH:4]=[CH:5][C:6]([C:9]2[N:10]=[CH:11][C:12](=[O:15])[NH:13][CH:14]=2)=[CH:7][CH:8]=1)[C:17]([NH2:18])=[O:16]

Participants

Procedure

5-(4-Aminophenyl)-2(1H)-pyrazinone hydrochloride (1.0 g) was dissolved in water (25 ml), to which solution potassium cyanate (0.4 g) and 4-dimethylaminopyridine (about 0.005 g) were added. The mixture was stirred at room temperature for 18 hours and the resulting suspended material collected by filtration. This was washed in hot dimethylformamide (30 ml), the insoluble material being collected and washed with water to afford the title compound, m.p. >300° C.; n.m.r. δ (DMSO-d6) 5.90 (s, 2H, --CONH2), 7.98, 8.10 (2d, 2H, pyridine H's); ν (liquid paraffin) 1710, 1665 cm-1.