Piperidine → 5-(3-bromo-pyridin-5-yl)-1-(2,4-difluoro-phenyl)-3-pentafluoroethyl-4,5-dihydro-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

1-(5-Bromo-pyridin-3-yl)-4,4,5,5,5-pentafluoro-pent-1-en-3-one (2.9 g, 8.6 mmol) prepared in Step 3, 2,4-difluorophenylhydrazine hydrochloride (2.4 g, 8.6 mmol), and piperidine (1.7 mL, 17.3 mmol) were added to ethanol (86.4 mL). The reaction mixture was stirred at 90° C. for 18 hours, concentrated under reduced pressure, and then ethyl acetate was added thereto. The mixture was washed with distilled water, dried on anhydrous magnesium sulfate, and then concentrated under reduced pressure to give a yellow liquid residue. The resulting residue was purified by silica gel column chromatography (eluent: ethyl acetate/n-hexane=1/9) to give 2.4 g of the titled compound as a yellow solid.

Provenance & Evidence