反应详情

温度

0 °C

A solution of NaNO2 (2.378 g, 34.5 mmol) in H2O (10 mL) was added dropwise at 0° C. to a solution of 2-(difluoromethoxy)aniline (3.59 mL, 28.7 mmol) in 6 M HCl aqueous solution (28.7 mL, 172 mmol). After stirring for 15 min, the resulting aqueous solution was added to a suspension of methyl 4-methoxyacetoacetate (3.72 mL, 28.7 mmol) and NaOAc (14.14 g, 172 mmol) in MeOH (50 mL) pre-cooled at 0° C. The precipitate was collected by filtration, washed with water, and dissolved in AcOEt. The organic solution was washed with water, saturated NaHCO3 aqueous solution and brine, dried over MgSO4, and concentrated under reduced pressure. The residue was washed with hexane/AcOEt (3/1) to give the title compound (8.70 g, 96% yield) as yellow crystals: 1H NMR (300 MHz, CDCl3): δ ppm 3.51 (3H, s), 3.89 (3H×0.5, s), 3.94 (3H×0.5, s), 4.68 (1H×0.5, s), 4.70 (1H×0.5, s), 6.63 (1H×0.5, t, J=72.7 Hz), 6.66 (1H×0.5, t, J=72.3 Hz), 7.10-7.34 (4H, m), 7.67 (1H×0.5, dd, J=8.3, 1.5 Hz), 7.90 (1H×0.5, dd, J=8.3, 1.5 Hz), 13.14 (1H×0.5, s), 14.96 (1H×0.5, br s).

1. filtrationThe precipitate was collected by filtration
2. washwashed with water
3. dissolutiondissolved in AcOEt
4. washThe organic solution was washed with water, saturated NaHCO3 aqueous solution and brine
5. dry with materialdried over MgSO4
6. concentrationconcentrated under reduced pressure
7. washThe residue was washed with hexane/AcOEt (3/1)