反应详情

In a 250 ml round flask, (5-fluoro-3-nitro-pyridin-2-yloxy)-acetic acid methyl ester (1.35 g, 5.87 mmol) and tin tetrachloride (4.45 g, 23.48 mmol) were dissolved in 15 ml of concentrated hydrochloric acid, and then stirred at 80 t for 1 hour. The reaction mixture was cooled to room temperature, neutralized with 10% sodium hydroxide solution, and extracted with ethyl acetate. The combined organic layer was washed with water and saturated saline solution, dried over anhydrous sodium sulfate (Na2SO4), filtered and evaporated under reduced pressure. The resulting solid was recrystallized from tetrahydrofuran and methanol to obtain 7-fluoro-1H-pyrido[2,3-b][1,4]oxazin-2-one as beige solid (0.70 g, 71%).

1. extractionextracted with ethyl acetate
2. washThe combined organic layer was washed with water and saturated saline solution
3. dry with materialdried over anhydrous sodium sulfate (Na2SO4)
4. filtrationfiltered
5. customevaporated under reduced pressure
6. customThe resulting solid was recrystallized from tetrahydrofuran and methanol