反应详情

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.

1. temperatureto reflux for 6 hours
2. concentrationThe reaction mixture was concentrated
3. customThe residue was purified by column chromatography on silica gel (eluent