反应详情

10% palladium on carbon (3.0 g) was added to a solution of the 1-(2-fluoropyridin-4-yl)-2-(3-trifluoromethylphenyl)-ethane-1,2-dione 1-oxime (4) (8.0 g, 27 mmol) in ethanol (400 mL) at ambient temperature. The reaction vessel was vacuum purged with hydrogen and vigorously stirred for 10 hrs. After the reaction was complete, the solution was filtered through a pad of celite, and concentrated to give a yellow solid. The residue could be purified by recrystalization from methylene chloride and hexane. Alternatively, non polar impurities could be removed by filtration though silica gel starting with 5% methanol in methylene chloride to 5% methanol, 0.5% ammonium hydroxide in methylene chloride. Colorless solid (91%): mp 128-129° C.; 1H NMR (300 MHz, CD3OD) d 8.01 (d, J=5.0 Hz, 1 H, Ar), 7.53 (m, 1 H, Ar), 7.49 (m, 2 H, Ar), 7.43 (s, 1 H, Ar), 7.06 (d, J=5.0 Hz, 1 H, Ar), 6.86 (s, 1 H, Ar), 4.96 (d, J=5.0 Hz, 1 H, CH), 4.12 (d, J=5.0 Hz, 1 H, CH).

1. custompurged with hydrogen
2. filtrationthe solution was filtered through a pad of celite
3. concentrationconcentrated
4. customto give a yellow solid
5. customThe residue could be purified by recrystalization from methylene chloride and hexane
6. customAlternatively, non polar impurities could be removed by filtration though silica gel starting with 5% methanol in methylene chloride to 5% methanol, 0.5% ammonium hydroxide in methylene chloride