反应详情

温度

-10 °C

4-amino-3-methyl-2-(trifluoromethyl)benzonitrile (CAS 573764-86-0, 2.0 g, 9.99 mmol) was dissolved in fluoroboric acid, HBF4 solution (15 mL) at −10° C. (ice/MeOH). To the pre-cooled solution was added NaNO2, (689 mg, 9.992 mmol) in 2 mL H2O drop by drop under constant stirring. The reaction mixture was allowed to stir for 15 min at −10° C. and filtered off. The white residue was washed with cold EtOH and cold ether to get the diazosalt as a white crystalline solid. The salt is dried over high vacuum for 4-5 h. to provide 1.9 g. The salt was heated up (>250° C.) and sublimed under reduced pressure to get the crude fluoro compound as an oil. The oil is chromatographed to get the pure 4-fluoro-3-methyl-2-(trifluoromethyl)benzonitrile as a clear oil (700 mg): 1H NMR (400 MHz, CDCl3, δ in ppm) 7.68 (dd, J=5.0, 9.0 Hz, 1H), 7.33 (t, J=9 Hz, 1H), 2.43 (quin, J=2 Hz, 3H).

1. customat −10° C.
2. filtrationfiltered off
3. washThe white residue was washed with cold EtOH and cold ether
4. customto get the diazosalt as a white crystalline solid
5. customThe salt is dried over high vacuum for 4-5 h.
6. customto provide 1.9 g
7. temperatureThe salt was heated up (>250° C.)
8. customsublimed under reduced pressure to get the crude fluoro compound as an oil
9. customThe oil is chromatographed