反应详情

温度

95 °C

The title compound was prepared according to the procedure described in Org. Prep. and Proc. Int., 29 (1), 117-122 (1997). A suspension of lithium 4-chloro-3-fluoropicolinate (20.0 g, 136 mmol) and sodium bromide (28.0 g, 272 mmol, 2 eq) in thionyl chloride (99 mL, 1.36 mmol, 10 eq) was heated to reflux (95° C.) with an argon flush. The reaction was refluxed for 2 days then thionyl chloride (50 mL, 680 mmol, 5 eq) was added again and the reaction was refluxed for 3 more days. The mixture was then evaporated and the residue cooled down to 0° C. Methanol (300 mL) was cautiously added by portions and the mixture was stirred at 23° C. overnight. The reaction was then partitioned into ethyl acetate/sat. aq sodium carbonate and the aqueous phase was extracted with ethyl acetate. The combined organic layers were dried over magnesium sulfate, filtered and concentrated. The residue was dissolved in boiling hexanes and the residual tar was decanted. The filtrate was evaporated to give the title material (24.36 g, 94%) as a solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 3.92 (3H, s), 8.01 (1H, t, J=5.1 Hz), 8.50 (1H, d, J=5.1 Hz). LC/MS (M+H)+: 190.

1. temperaturewas heated
2. customflush
3. temperatureThe reaction was refluxed for 2 days
4. temperaturethe reaction was refluxed for 3 more days
5. customThe mixture was then evaporated
6. temperaturethe residue cooled down to 0° C
7. additionMethanol (300 mL) was cautiously added by portions
8. customThe reaction was then partitioned into ethyl acetate/
9. extractionaq sodium carbonate and the aqueous phase was extracted with ethyl acetate
10. dry with materialThe combined organic layers were dried over magnesium sulfate
11. filtrationfiltered
12. concentrationconcentrated
13. dissolutionThe residue was dissolved
14. customthe residual tar was decanted
15. customThe filtrate was evaporated