反应详情

温度

150 °C

4-Hydroxy-cinnoline-3-carboxylic acid, methyl ester (6 g), prepared accoring to J. Chem. Soc. 687 (1968), is reacted with 2-aminopyridine (16.6 g, stepwise added) in polyphosphoric acid (300 g:160 g of H3PO4 and 140 g of P2O5) under stirring at 150° C. for 10 hours. After cooling, dilution with ice water and neutralization with 35% NaOH, the precipitate is filtered and washed with water. Crystallization from dimethylformamide gives 4.9 g of 4-hydroxy-N-(2-pyridyl)-cinnoline-3-carboxamide, m.p. 341°-343° C.

1. temperatureAfter cooling
2. filtrationdilution with ice water and neutralization with 35% NaOH, the precipitate is filtered
3. washwashed with water
4. customCrystallization from dimethylformamide