反应详情

温度

0 °C

A solution of 2,5-dichloronicotinic acid (20.2 g, 0.105 mol) in methanol (500 mL) was cooled to 0° C. and neat thionyl chloride (38 mL, 63 g, 0.525 mol) was added over ˜30 min. The reaction mixture was stirred at 0° C. for 1 hour. The cooling bath was removed, the reaction temperature was allowed to warm to rt, and the reaction was allowed to stir for an additional 2 days at room temperature and the solvent was removed under reduced pressure to give an off-white residue. The residue was dissolved in Et2O (˜500 mL) and the resulting solution was washed successively with saturated aqueous NaHCO3 solution (˜300 mL), water (˜300 mL), and brine (˜300 mL). The organic layer was separated, dried over anhydrous MgSO4, and filtered. Removal of the solvent under reduced pressure yielded methyl 2,5-dichloronicotinate (21.0 g, 97%) as a white solid.

1. customThe cooling bath was removed
2. temperatureto warm to rt
3. stirringto stir for an additional 2 days at room temperature
4. customthe solvent was removed under reduced pressure
5. customto give an off-white residue
6. washthe resulting solution was washed successively with saturated aqueous NaHCO3 solution (˜300 mL), water (˜300 mL), and brine (˜300 mL)
7. customThe organic layer was separated
8. dry with materialdried over anhydrous MgSO4
9. filtrationfiltered
10. customRemoval of the solvent under reduced pressure