反应详情

To a suspension of potassium thiocyanate (33.8 g, 348 mmol) in acetic acid (150 mL) was added 6-bromopyridin-3-amine (15.2 g, 88.1 mmol), and the mixture was stirred at room temperature for 15 min. A solution of bromine (18.4 g, 115 mmol) in acetic acid (200 mL) was added dropwise to the obtained solution at room temperature for 30 min or more. After the completion of the dropwise addition, the mixture was stirred at room temperature for 6 hr. The yielded yellow solid was filtered off, and the filtrate was concentrated under reduced pressure. The residue was suspended in tetrahydrofuran (200 mL) and ethyl acetate (200 mL), the suspension was washed with saturated aqueous sodium hydrogen carbonate solution (300 mL×2) and saturated brine (200 mL), dried over anhydrous magnesium sulfate, and decolorized with activated carbon. The insoluble material was filtered off, and the filtrate was concentrated under reduced pressure. The obtained crude product was recrystallized from tetrahydrofuran and diisopropyl ether to give the title compound (15.8 g, 78%) as a pale-brown solid.

1. additionAfter the completion of the dropwise addition
2. stirringthe mixture was stirred at room temperature for 6 hr
3. filtrationThe yielded yellow solid was filtered off
4. concentrationthe filtrate was concentrated under reduced pressure
5. washethyl acetate (200 mL), the suspension was washed with saturated aqueous sodium hydrogen carbonate solution (300 mL×2) and saturated brine (200 mL)
6. dry with materialdried over anhydrous magnesium sulfate
7. filtrationThe insoluble material was filtered off
8. concentrationthe filtrate was concentrated under reduced pressure
9. customThe obtained crude product
10. customwas recrystallized from tetrahydrofuran and diisopropyl ether