反应详情

To 4-t-butoxy-3-chloro-2,5,6-trifluoropyridine (24.92 g, 0.104 mmol) in 100 mL of methanol was added 2.5 g of Pearlman's catalyst (Aldrich Chemical Co.), and the mixture was stirred at ambient temperature for 14 hours under and atmosphere of hydrogen. An additional 2.5 g of catalyst was added, and the mixture was stirred for another 22 hours. The mixture was filtered, the filtrate was concentrated, and the residue was extracted with hexane/ether. After filtration, the solvent was removed by evaporation, and the residue was purified by flash chromatography (ethyl acetate:hexane 1:16) to yield 12.05 g of 4-t-butoxy-2,3,6-trifluoropyridine. MS 206 (M+H)+, 233 (M+18)+ ; 1H NMR (CDCl3)∂: 1.52 (s, 9H), 6.5 (m, 1H); 19F NMR (CDCl3, CFCl3 as reference)∂: 72.60 (dd, J1 =14.3, J2 =21.0 Hz), 89.74 (dd, J1 =14.3, J2 =21.0 Hz), 164.68 (dt, J1 =4.2, J2 =21.0 Hz).

1. filtrationThe mixture was filtered
2. concentrationthe filtrate was concentrated
3. extractionthe residue was extracted with hexane/ether
4. filtrationAfter filtration
5. customthe solvent was removed by evaporation
6. customthe residue was purified by flash chromatography (ethyl acetate:hexane 1:16)