Water → 2-(4-FLUOROPHENYL)-6-(TRIFLUOROMETHYL)PYRAZOLO[1,5-A]PYRIDINE

Participants

Reaction Steps

To a solution of 1-(4-fluorophenyl)-2-(5-trifluoromethyl-2-pyridinyl)ethanone oxime (2.0 g, 6.7 mmol) in ethyl acetate (8 ml) at 7° C. was added methanesulfonyl chloride (0.52 ml, 6.7 mmol) over 3 minutes. The reaction mixture was stirred for 5 minutes before the dropwise addition of triethylamine (1.92 ml, 13.8 mmol) over 5 minutes. The reaction temperature was allowed to rise to 30° C. and the resulting suspension stirred at this temperature for two hours. Iron (II) chloride (8 mg) was then added and the mixture heated at reflux for 40 minute s before the addition of further iron (II) chloride (5 mg) and heating at reflux for 6 hours. The reaction mixture was then cooled to room temperature and water was added (5 ml). The phases were separated and the aqueous phase re-extracted with ethyl acetate. The organic extracts were combined, washed with water (5 ml) and evaporated in vacuo to give an orange-brown solid. The solid was triturated with isohexane (25 ml), the mixture filtered, the filter cake washed with isohexane (2×10 ml) and dried to give the title compound as a dull orange solid (1.06 g, 56%).

Provenance & Evidence