Sodium Hydroxide → 7-bromo-1H,2H,3H-pyrido[2,3-b][1,4]oxazin-2-one

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Reaction Steps

In a 10 ml round flask, (5-bromo-3-nitro-pyridin-2-yloxy)-acetic acid methyl ester (144 mg, 0.49 mmol) and tin tetrachloride (375 mg, 1.96 mmol) were dissolved in 3 ml of concentrated hydrochloric acid, and then stirred at 80□ for 1 hour. The reaction mixture was cooled to room temperature, neutralized with 10% sodium hydroxide solution, and extracted with dichloromethane. 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-bromo-1H-pyrido[2,3-b][1,4]oxazin-2-one as white solid (59 mg, 52%).

Provenance & Evidence