反应详情

A solution of sodium methoxide (18 g, 83 mmol, 25% in methanol) is added dropwise to a solution of pentafluorobenzonitrile (7.72 g, 40 mmol) in 60 mL methanol over 15 min. The reaction is heated to reflux for 3 hours, cooled to room temperature and then poured into 150 mL ice water. The product is then extracted with diethyl ether (100 mL×2), and the combined organic layers are washed with brine (50 mL), dried over magnesium sulfate and concentrated in vacuo. The residue is then chromatographed on silica gel, eluting with hexane:ethyl acetate (97:3 to 88:12 gradient) to yield 6.18 g (71%) of Compound 43 as a colorless oil. 1H-NMR (CDCl3) 4.16 (s, 3H); 4.10 (s, 3H). 19F-NMR (CDCl3) 134.39 (dd, J=10.1 and 20.3 Hz, 1 F); 150.80 (d, J=7.1 Hz, 1 F); 158.00 (d, J=21.4 Hz, 1 F). Anal. calc. for C9H6F3NO2 : C, 49.78; H, 2.78; N, 6.45. Found: C, 49.71; H, 2.78; N, 6.56. A second product, 3,5-difluoro-2,4,6-trimethoxybenzonitrile, is also isolated from the reaction mixture as a colorless solid (1.09 g; 12%). 1H-NMR (CDCl3) 4.12 (s, 3H); 4.07 (s, 6H). 19F-NMR (CDCl3) 152.11 (s).

1. temperatureThe reaction is heated
2. temperatureto reflux for 3 hours
3. extractionThe product is then extracted with diethyl ether (100 mL×2)
4. washthe combined organic layers are washed with brine (50 mL)
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated in vacuo
7. customThe residue is then chromatographed on silica gel
8. washeluting with hexane:ethyl acetate (97:3 to 88:12 gradient)