Water → 2-(3-Chloro-4-Fluorophenyl)-6-Trifluoromethylpyrazolo[1,5-a]Pyridine

Participants

Reaction Steps

To a suspension of 1-(3-chloro-4-fluorophenyl)-2-(5-trifluoromethyl-2-pyridinyl)ethanone oxime (15.56 g, 46.8 mmol) in DME (64 ml) at 5° C. was added TFAA (6.6 ml, 46.8 mmol) and the mixture stirred for 10 minutes. Triethylamine (19.6 ml, 140.4 mmol) was then added dropwise over 15 min. After the addition was complete, the reaction was then warmed to room temperature. After stirring for 1 hour, iron (II) chloride (60 mg) was added and the mixture was then heated to 75° C. for 1 hour then allowed to cool. The mixture was poured into water (500 ml) and extracted with dichloromethane (300 ml). The organic extracts were dried over MgSO4 and concentrated under reduced pressure to ca. 50 ml. This residue was purified by filtration through a layer of silica gel washing with further dichloromethane. The filtrate was concentrated to dryness to give 12 g (82%) of the title compound.

Provenance & Evidence