反应详情

13.3 g. of 5,6-Diamino-4-butylamino-2-methylpyridine-3-carboxylic acid, ethyl ester (0.05 Mol.) of Example 1 d and 4g. of glyoxal monohydrate, dissolved in 100 ml. of toluene, are refluxed, while the water formed is removed by means of a water separator. After about 3 hours, the reaction is complete and the solution is concentrated. The remaining oily residue is extracted twice with 50 ml. portions of gasoline and addition of activated charcoal. The gasoline extracts are cooled and the crystalline 8-butylamino-6-methylpyrido[2,3-b]pyrazine-7-carboxylic acid, ethyl ester is filtered off, yield 70%; m.p. 56°-58°.

1. customformed
2. customis removed by means of a water separator
3. concentrationthe solution is concentrated
4. extractionThe remaining oily residue is extracted twice with 50 ml
5. additionportions of gasoline and addition of activated charcoal
6. temperatureThe gasoline extracts are cooled
7. filtrationthe crystalline 8-butylamino-6-methylpyrido[2,3-b]pyrazine-7-carboxylic acid, ethyl ester is filtered off