Water → 5-Amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-oximinomethylpyrazole

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Reaction Steps

To a stirred solution of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-formylpyrazole (0.25 g) in ethanol (3 ml) was added hydroxylamine hydrochloride (0.075 g), sodium acetate (0.1 g) and water (0.1 ml). After stirring at room temperature overnight the mixture was evaporated. The residue was taken up in ether and washed with water, then brine, then dried and evaporated. The residue was crystallised from propan-2-ol/water and further purified by column chromatography on silica gel eluted with dichloromethane then dichloromethane:methanol (99:1). After combination and evaporation of suitable fractions the residue was further purified by column chromatography on silica gel eluted with ether. Combination and evaporation of suitable fractions gave the title compound as a white solid, m.p. 175-178° C.

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