(2,3-Dichlorophenyl)hydrazine → 1-(2,3-dichlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-5-amine

Participants

Reaction Steps

To a stirred suspension of 4,4,4-trifluoro-3-oxobutanenitrile (20 g, 145.98 mmol, 1.0 eq.) in ethanol (200 mL) was added (2,3-dichlorophenyl)hydrazine (47.5 g, 145.98 mmol, 1.0 eq) and refluxed for 3 h. Ethanol was evaporated, the residue diluted with water and extracted with ethyl acetate (300 mL×2), dried (Na2SO4), and the solvent evaporated under vacuum. The crude product was purified by CC using EtOAc/PE (3:7) as eluent to get 1-(2,3-dichlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-5-amine (17.02 g, 39.65%, yellow solid; TLC system: EtOAc/PE (1:1) Rf: 0.6).

Provenance & Evidence