Aluminium lithium hydride → 6-methyl-2H,3H,4H-pyrido[3,2-b][1,4]oxazine

Participants

Reaction Steps

A flask was charged with lithium aluminum hydride (607 mg, 16.0 mmol) was placed in an ice-water bath under an argon atmosphere. THF (13 mL) was added slowly. To this suspension was added slowly a solution of 6-methyl-4H-pyrido[3,2-b][1,4]oxazin-3-one (1.05 g, 6.40 mmol) in THF (13 mL). After the addition was completed, additional THF (9 mL) was added, and the reaction was stirred in the ice-water bath for 30 minutes. Ice-water bath was removed, the mixture was stirred at ambient temperature for 3 h. The mixture was cooled with an ice-water bath, and H2O (0.86 mL) was added slowly, followed by cooled aqueous NaOH solution (0.64 mL, 10%). The ice-water bath was removed, additional H2O (1.8 mL) was added. After stirring for 30 minutes, Celite and Na2SO4 were added. The mixture was filtered through Celite, and the Celite was washed with EtOAc. The filtrate and the washing were combined, dried over Na2SO4, and concentrated to give the title compound (0.96 g, quantitative yield) as a while solid. 1H NMR (CDCl3) δ 6.85 (d, 1H, J=8.0 Hz), 6.35 (d, 1H, J=8.0 Hz), 6.08 (bs, 1H), 4.19-4.16 (m, 2H), 3.54-3.52 (m, 2H), 2.31 (s, 3H).

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