反应详情

温度

70 °C

To a solution of methyl 4-amino-3,6-dichloropyridine-2-carboxylate (18 g, 81 mmol) in 100 mL fuming sulfuric acid was added bromine (15 mL, excess). The resulting mixture was heated to 70° C. for 30 min, then allowed to cool to room temperature. This material was poured into ice water (1000 mL) and extracted with EtOAc (4×500 mL). The combined organic extracts were dried (MgSO4), filtered and concentrated to yield a brown solid. The crude product was purified via reverse phase HPLC (50% acetonitrile/water) to give 21 g of 4-amino-3,6-dichloro-5-bromopyridine-2-carboxylic acid as a white solid (91% yield); mp 201-202° C.

1. temperatureto cool to room temperature
2. extractionextracted with EtOAc (4×500 mL)
3. dry with materialThe combined organic extracts were dried (MgSO4)
4. filtrationfiltered
5. concentrationconcentrated
6. customto yield a brown solid
7. customThe crude product was purified via reverse phase HPLC (50% acetonitrile/water)