反应详情

温度

2.5 °C

To a cooled (−60-65° C.) solution of 2,6-dibromo-pyridin-4-yl-thiourea (0.50 g, 1.61 mmol) in THF (100 mL) was added bromine solution (0.20 mL in 45 mL THF, 3.69 mmol) drop wise over a period of 30 min maintaining the temperature to −60-65° C. The reaction mixture was stirred for 15 min at the same temperature and then slowly allowed to come to room temperature. The resulting mixture was heated up to 40° C. for 5 h. After completion of reaction (TLC monitoring), THF was distilled off, basified with aq. NH3 (25% solution, pH 10-12) and then extracted with ethyl acetate (3×50 mL). The combined organics was washed with water, dried (Na2SO4), filtered and concentrated. The crude residue was purified over silica gel (100-200 M, 10% ethyl acetate:hexane) to get the desired product as a white solid (0.10 g, 20%).

1. customto come to room temperature
2. temperatureThe resulting mixture was heated up to 40° C. for 5 h
3. distillationwas distilled off
4. extractionextracted with ethyl acetate (3×50 mL)
5. washThe combined organics was washed with water
6. dry with materialdried (Na2SO4)
7. filtrationfiltered
8. concentrationconcentrated
9. customThe crude residue was purified over silica gel (100-200 M, 10% ethyl acetate:hexane)