反应详情

To a solution of E-2-fluoro-5-trifluoromethoxy-benzaldehyde oxime (47.5 g, 213 mmol) in THF (400 mL) was added triethylamine (65.0 mL, 466 mmol). The mixture was cooled in an ice bath and trifluoroacetic anhydride (32.8 mL, 236 mmol) was added at such a rate that the temperature was kept <30° C. After 1 h at rt all volatiles were evaporated (40° C., 200 mbar). The oily residue was partitioned (ether/water), the organic phase was dried over sodium sulfate and concentrated. Distillation (24 mbar, T=80-83° C.) afforded the title compound (36.1 g, 83%) that was sufficiently pure to be used in the next step. MS: m/e=205 [M]+.

1. temperatureThe mixture was cooled in an ice bath
2. customwas kept <30° C
3. customAfter 1 h at rt all volatiles were evaporated (40° C., 200 mbar)
4. customThe oily residue was partitioned (ether/water)
5. dry with materialthe organic phase was dried over sodium sulfate
6. concentrationconcentrated
7. distillationDistillation (24 mbar, T=80-83° C.)