Hydrochloric Acid → 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid [2-(2,4-dichlorophenyl)-1-methyl-ethyl]-hydroxy-amide

Participants

Reaction Steps

A solution of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carbonyl chloride (2.10 g; 11.0 mmol) in dichloromethane (5 ml) was added dropwise to a stirred suspension of N-[2-(2,4-dichlorophenyl)-1-methyl-ethyl]-hydroxylamine (2.0 g; 9.10 mmol), prepared as described in example P17, triethylamine (3.10 ml; 22 mmol) in dichloromethane (15 ml) at 0° C. The reaction mixture was stirred over night at ambient temperature. The reaction mixture was poured onto 1M HCl (50 ml), extracted with dichloromethane (3×20 ml) and then dried over Na2SO4. After removal of the solvent the residue (5.08 g) was purified by flash chromatography over silica gel (eluant: c-hexane/ethyl acetate 7:3). 1.51 g (43.8% of theory) of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid [2-(2,4-dichlorophenyl)-1-methyl-ethyl]-hydroxy-amide (compound 1.028) was obtained in form of a white solid (m.p. 162-167° C.).

Provenance & Evidence