反应详情

温度

0 °C

A solution of sodium nitrite (0.96 g, 14 mmol) in H2O (5 mL) was added dropwise to a solution of 2,2-difluoro-1,3-benzodioxol-4-amine (2.0 g, 12 mmol) in 6 M HCl aqueous solution (12 mL, 72 mmol) at 0° C. After stirring for 15 min at 0° C., the mixture was added to a suspension of 2,4-pentanedione (1.2 mL, 12 mmol) and sodium acetate (5.9 g, 72 mmol) in MeOH (20 mL) pre-cooled at 0° C. The formed precipitate was collected by filtration, washed with water and dissolved in AcOEt. The organic solution was washed with saturated NaHCO3 aqueous solution and brine, dried over MgSO4, filtered and concentrated under reduced pressure to give the title compound (3.0 g, 90% yield) as orange crystals: 1H NMR (300 MHz, CDCl3): δ ppm 2.49 (3H, s), 2.63 (3H, s), 6.88 (1H, dd, J=8.0, 1.1 Hz), 7.13 (1H, t, J=8.1 Hz), 7.30 (1H, dd, J=8.5, 1.1 Hz), 14.56 (1H, brs).

1. temperaturepre-cooled at 0° C
2. filtrationThe formed precipitate was collected by filtration
3. washwashed with water
4. dissolutiondissolved in AcOEt
5. washThe organic solution was washed with saturated NaHCO3 aqueous solution and brine
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure