反应详情

5-Chloro-2-hydroxynicotinic acid (174 mg, 1 mmol), 3,5-bis(trifluoromethyl)aniline (275 mg, 1.2 mmol) and pyridine (316 mg, 4 mmol) were dissolved in tetrahydrofuran (20 mL) and dichloromethane (10 mL). Phosphorus oxychloride (0.112 ml, 1.2 mmol) was added, and the mixture was stirred at room temperature for 2 hours. The reaction mixture was poured into ethyl acetate (100 mL) and 0.2 N hydrochloric acid (100 mL), filtered through celite after stirring for 30 minutes, and the water layer of the filtrate was extracted with ethyl acetate. After the combined ethyl acetate layer was washed with water and brine one after another, dried over anhydrous magnesium sulfate, the solvent was evaporated under reduced pressure. The residue was purified by column chromatography on silica gel (n-hexane:ethyl acetate=2:1→1:1) to give a light yellow solid. This was suspended and washed with ethanol under heating at reflux to give the title compound (183 mg, 47.6%) as a white crystal.

1. filtrationfiltered through celite
2. stirringafter stirring for 30 minutes
3. extractionthe water layer of the filtrate was extracted with ethyl acetate
4. washAfter the combined ethyl acetate layer was washed with water and brine one after another,
5. dry with materialdried over anhydrous magnesium sulfate
6. customthe solvent was evaporated under reduced pressure
7. customThe residue was purified by column chromatography on silica gel (n-hexane:ethyl acetate=2:1→1:1)
8. customto give a light yellow solid
9. washwashed with ethanol
10. temperatureunder heating
11. temperatureat reflux