反应详情

A solution of methyl 2-{[2-(difluoromethoxy)phenyl]hydrazono}-4-methoxy-3-oxobutanoate (8.70 g, 27.5 mmol) in N,N-dimethylformamide dimethyl acetal (60 mL) was refluxed for 3 h and stirred at room temperature for 3 days. The precipitate was collected by filtration and washed with hexane/AcOEt (3/1) to give the title compound (7.92 g, 88% yield) as yellow crystals: 1H NMR (300 MHz, CDCl3): δ ppm 3.89 (3H, s), 3.96 (3H, s), 6.55 (1H, d, J=72.7 Hz), 7.35-7.45 (2H, m), 7.49-7.56 (1H, m), 7.61 (1H, dd, J=7.9, 1.5 Hz), 7.73 (1H, s).

1. filtrationThe precipitate was collected by filtration
2. washwashed with hexane/AcOEt (3/1)