Methyl 3-aminopyrazinecarboxylate → 3-(3-Oxo-butyrylamino)-pyrazine-2-carboxylic acid methyl ester
Reaction equation
[CH3:1][O:2][C:3]([C:5]1[C:10]([NH2:11])=[N:9][CH:8]=[CH:7][N:6]=1)=[O:4].CC1(C)[O:18][C:17](=O)[CH:16]=[C:15]([CH3:20])[O:14]1>>[CH3:1][O:2][C:3]([C:5]1[C:10]([NH:11][C:17](=[O:18])[CH2:16][C:15](=[O:14])[CH3:20])=[N:9][CH:8]=[CH:7][N:6]=1)=[O:4]Participants
3
Procedure
3-Aminopyrazine-2-carboxylic acid methyl ester (12 g) and 2,2,6-trimethyl-[1,3]dioxin-4-one (15.6 ml) were heated to reflux for 6 hours. The reaction mixture was concentrated. The residue was purified by column chromatography on silica gel (eluent: ethyl acetate/hexane 4:1, then ethyl acetate) to give 3-(3-oxo-butyrylamino)-pyrazine-2-carboxylic acid methyl ester as a beige solid (15 g). 1H-NMR (400 MHz, CDCl3): 2.33 (s, 3H), 3.91 (s, 2H), 4.05 (s, 3H), 8.40 (d, 1H), 8.51 (d, 1H), 10.06 (s, 1H) ppm.
Workup
- temperatureto reflux for 6 hours
- concentrationThe reaction mixture was concentrated