反应详情

3-(3-Oxo-butyrylamino)-pyrazine-2-carboxylic acid methyl ester (Example 6.1) (15 g) in methanol (80 ml) was added to a suspension of sodium methoxide (7.2 g) in methanol (80 ml). The suspension was heated to reflux for 2 hours and then stored for 16 hours at ambient temperature. The mixture was filtered and the filtrate was acidified to pH 1 by addition of concentrated hydrochloric acid (36% by weight in water) and then filtered again. The solid was washed with water and then diethyl ether to give 1-(6,8-dihydroxy-pyrido[2,3-b]pyrazin-7-yl)-ethanone (10.1 g). 1H-NMR (400 MHz, d6-DMSO): 2.70 (s, 3H), 8.60 (d, 1H), 8.71 (d, 1H), 12.2 (s, 1H), 16.25 (s, 1H) ppm.

1. temperatureThe suspension was heated
2. temperatureto reflux for 2 hours
3. filtrationThe mixture was filtered
4. additionthe filtrate was acidified to pH 1 by addition of concentrated hydrochloric acid (36% by weight in water)
5. filtrationfiltered again
6. washThe solid was washed with water