Hydrochloric Acid → 1-(2-chlorophenyl)-5-(4-chlorophenyl)-4-methoxy-3-vinylcarbonyl-1H-pyrazole

Participants

Reaction Steps

To a solution of 3-carboxy-1-(2-chlorophenyl)-5-(4-chlorophenyl)-4-methoxy-1H-pyrazole (1.09 g) in tetrahydrofuran (30 mL) was added dropwise methyl lithium (2.9 mL, 1.04 M diethylether solution) at −78° C. under nitrogen-gas atmosphere and the mixture was stirred at the same temperature for 30 minutes After warming to room temperature, to the reaction mixture was added dropwise vinylmagnesium bromide (7.7 mL, 0.97 M tetrahydrofuran solution) and the mixture was stirred at room temperature for 3 hours. To the reaction mixture was added water and an aqueous 1N HCl solution. After stirring, the mixture was extracted with ethyl acetate. The organic layer was dried over magnesium sulfate and filtered. The filtrate was concentrated in vacuo and the resultant crude product was purified by column chromatography on silica gel (solvent: hexane/ethyl acetate=90/10 to 85/15) to obtain 1-(2-chlorophenyl)-5-(4-chlorophenyl)-4-methoxy-3-vinylcarbonyl-1H-pyrazole (780 mg, yield: 70%) as a colorless solid.

Provenance & Evidence