Chlorine → ethyl 4-chloro-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-1H-pyrazole-3-carboxylate

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Reaction Steps

To a solution of ethyl 5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-1H-pyrazole-3-carboxylate (3.0 g, 7.6 mmol) in acetic acid (30 ml) at room temperature was bubbled chlorine gas for 10 minutes. The reaction mixture was stirred at room temperature for 2 hours and the resulting solution was quenched with water (100 ml). The organic solution was extracted with diethyl ether (100 ml×2). With saturated sodium bicarbonate solution, remained acetic acid was removed and organic phase was evaporated with reduced pressure. The crude residue was purified with silica gel column (hexane/ethyl acetate=5/1) to produce title compound (3.1 g, 95% yield) as white solid.

Provenance & Evidence