反应详情

4,5-difluoro-2-nitroaniline (3.48 g, 20 mmol), 2,2-dimethoxypropane (11.9 mL, 100 mmol), and trifluoroacetic acid (1.6 mL, 21 mmol) were dissolved in toluene (40 mL) and stirred at room temperature for 1 h. A boron-pyridine complex (2.12 mL, 21 mmol) was slowly added. The reaction mixture was stirred for 20 h. The solvent was evaporated in vacuo, and the residue was taken up into water and extracted with dichloromethane. The organic extract was dried (Na2SO4) and concentrated in vacuo. The residue was chromatographed on a column of aminopropyl-silica gel eluting with hexane/ethyl acetate (30:1) to give 2.42 g (56%) of the title compound as a bright orange solid.

1. additionA boron-pyridine complex (2.12 mL, 21 mmol) was slowly added
2. stirringThe reaction mixture was stirred for 20 h
3. customThe solvent was evaporated in vacuo
4. extractionextracted with dichloromethane
5. extractionThe organic extract
6. dry with materialwas dried (Na2SO4)
7. concentrationconcentrated in vacuo
8. customThe residue was chromatographed on a column of aminopropyl-silica gel eluting with hexane/ethyl acetate (30:1)