Water → 5-methyl-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazine

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Reaction Steps

5-methyl-1H-pyrido[2,3-b][1,4]oxazin-2-one (424 mg, 2.58 mmol) was dissolved in 20 ml of anhydrous tetrahydrofuran under nitrogen atmosphere, and then cooled to 0□. 1.0M Lithium aluminum hydride dissolved in tetrahydrofuran (5.16 ml, 5.16 mmol) was added thereto dropwise and then stirred for 30 minutes. The reaction temperature was raised to room temperature and then stirred for 1 hour. The reaction mixture was cooled to 0□ again and water (0.2 ml), 10% sodium hydroxide solution (0.4 ml) and water (0.6 ml) were added thereto dropwise in this order, and stirred vigorously at room temperature for 1 hour. The formed precipitate was filtered and washed with excess ethyl acetate. The filtrate was washed with water and saturated saline solution, dried over anhydrous sodium sulfate (Na2SO4), filtered and evaporated under reduced pressure to obtain 5-methyl-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazine as white solid (100 mg, 26% in two steps).

Provenance & Evidence