Boron trifluoride etherate → 5-Butyl-3-(trifluoromethyl)-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-Hexyne (3.37 mL, 29.4 mmol) in THF (30 mL) was added n-BuLi (2.78 M, 10.2 mL, 29.4 mmol). The solution was stirred at −78° C. for 30 minutes then CF3CO2Et (3.5 mL, 29.35 mL) and BF3—OEt2 were added successively. The reaction was further stirred at −78° C. for 2 h and was quenched with satd. NH4Cl. It was then warmed up to the room temperature. The THF was removed, the residue taken into ether, washed with saturated brine solution, dried over Na2SO4 and reduced. The crude product was then dissolved in benzene (25 mL) and hydrazine (29.4 mmol) was added. The reaction mixture was refluxed overnight, then cooled, the solvent evaporated, and the residue taken into CH2Cl2 (30 mL), washed with brine, dried over Na2SO4 and concentrated to give the title compound as colorless oil.

Provenance & Evidence