反应详情

4-Hydroxy-cinnoline-3-carboxylic acid (8.8 g) is dissolved in dichloromethane (600 ml) in the presence of triethylamine (5.6 g). To this solution ethyl chloroformate (6 g) diluted with dichloromethane (50 ml) is added dropwise under stirring at a temperature varying between 0° C. and about 5° C. The mixture is allowed to react at 0°-5° C. for 1 hour, then 2-methylamino-pyridine (4.55 g) is added. The reaction mixture is kept at 0°-5° C. for 1 hour, then at room temperature for 2 hours, under stirring. The organic solution is washed with 2.5% NaHCO3 and water, then is evaporated to dryness in vacuo. The residue is purified over a SiO2 column using ethyl acetate, then ethylacetate-methanol=95:5 as eluents. Crystallization from ethanol yields 1.65 g of 4-hydroxy-N-methyl-N-(2-pyridyl)-cinnoline-3-carboxamide, m.p. 237°-239° C., NMR (DMSO d6) δ ppm: 3.43 (s) (3H, CH3), 7.0-8.3 (m) (8H, phenyl and pyridyl protons).

1. additionis added dropwise
2. customvarying between 0° C. and about 5° C
3. customto react at 0°-5° C. for 1 hour
4. waitat room temperature for 2 hours
5. stirringunder stirring
6. washThe organic solution is washed with 2.5% NaHCO3 and water
7. customis evaporated to dryness in vacuo
8. customThe residue is purified over a SiO2 column
9. customCrystallization from ethanol