反应详情

To 5-bromo-2-hydroxypyridine-3-carboxylic acid (Intermediate 10, 14 g, 64.2 mmol) was added thionyl chloride (70 mL) and dimethylformamide (8 mL). The reaction mixture was heated to reflux for 3 h. After cooling, the excess thionyl chloride was removed by rotary evaporation and the residue was poured into water (1 L) and extracted with ethyl acetate (3×100 mL). The organic layer was dried over anhydrous sodium sulphate then filtered and concentrated to afford 7.0 g (47%) of 5-bromo-2-chloropyridine-3-carboxylic acid.

1. temperatureThe reaction mixture was heated
2. temperatureto reflux for 3 h
3. temperatureAfter cooling
4. customthe excess thionyl chloride was removed by rotary evaporation
5. additionthe residue was poured into water (1 L)
6. extractionextracted with ethyl acetate (3×100 mL)
7. dry with materialThe organic layer was dried over anhydrous sodium sulphate
8. filtrationthen filtered
9. concentrationconcentrated