反应详情

To a solution of 7-bromo-4-methyl-3,4-dihydro-2H-benzo[1,4]oxazine (1.8 g, 7.9 mmol) in THF (15 mL) was added a solution of n-butyllitium in hexane (2.6 mL, 2.5 N, 6.5 mmol) at −78° C. and kept for 10 min. To the mixture was added a solution of 3-ethoxy-4,N-dimethoxy-N-methyl-benzamide (1.4 g, 6.0 mmol) in THF (10 mL) at −78° C. After 30 min, isopropanol (2 mL) and water (30 mL) was added to the mixture, and the cold bath was removed. The mixture was stirred at room temperature for 20 min. The mixture was extracted with ethyl acetate (50 mL) and water (50 mL). The aqueous layer was extracted with ethyl acetate (50 mL). The combined organic layers was washed with water (50 mL), brine (50 mL) and dried over MgSO4. Removal of solvent and chromatography (Silica Gel) gave (3-ethoxy-4-methoxy-phenyl)-(4-methyl-3,4-dihydro-2H-benzo[1,4]oxazin-7-yl)-methanone as an oil (1.7 g, 87% yield): 1H NMR (CDCl3) δ 1.47 (t, J=7 Hz, 3H, CH3), 3.00 (s, 3H, CH3), 3.41 (t, J=4 Hz, 2H, CH2), 3.94 (s, 3H, CH3), 4.15 (q, J=7 Hz, 2H, CH2), 4.28 (t, J=5 Hz, 2H, CH2), 6.64 (d, J=8 Hz, 1H, Ar), 6.88 (d, J=8 Hz, 1H, Ar), 7.31-7.41 (m, 4H, Ar).

1. waitAfter 30 min
2. customthe cold bath was removed
3. extractionThe mixture was extracted with ethyl acetate (50 mL) and water (50 mL)
4. extractionThe aqueous layer was extracted with ethyl acetate (50 mL)
5. washThe combined organic layers was washed with water (50 mL), brine (50 mL)
6. dry with materialdried over MgSO4
7. customRemoval of solvent and chromatography (Silica Gel)