反应详情

A solution of methyl 2-[(4-bromo-2,5-difluorophenyl)hydrazono]-4-methoxy-3-oxobutanoate (33 g, 90 mmol) in N,N-dimethylformamide dimethyl acetal (72 mL) was stirred at 110° C. for 3 h. After cooling to room temperature, the mixture was concentrated under reduce pressure. To the residue were added MeOH and silica gel The mixture was evaporated and purified by silica gel column chromatography eluting with hexane/AcOEt (1/0 to 0/1) and then AcOEt/MeOH (4/1) to give the title compound (27.9 g, 83% yield) as a brown gum: 1H NMR (300 MHz, DMSO-d5): δ ppm 3.80 (3H, s), 3.83 (3H, s), 8.01 (1H, dd, J=8.7, 6.8 Hz), 8.15 (1H, dd, J=9.8, 6.0 Hz), 8.55 (1H, d, J=1.5 Hz). LC-MS (ESI) m/z 376 [M+H]+.

1. concentrationthe mixture was concentrated
2. additionTo the residue were added MeOH and silica gel The mixture
3. customwas evaporated
4. custompurified by silica gel column chromatography
5. washeluting with hexane/AcOEt (1/0 to 0/1)