Iodine → 1-(4-chlorophenyl)-3-(2,5-dimethylpyrrol-1-yl)-5-iodo-1H-pyrazole

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Reaction Steps

Under argon atmosphere, a solution of 3-(2,5-dimethylpyrrol-1-yl)-1-(4-chlorophenyl)-1H-pyrazole (4.98 g) in tetrahydrofuran (40 ml) was cooled to −78° C., n-butyllithium (13.7 ml, 1.6M solution in n-hexane) was added dropwise thereto, and the mixture was stirred for 30 minutes. To this reaction solution was added dropwise a solution of iodine (5.58 g) in tetrahydrofuran (10 ml), the mixture was stirred for 30 minutes. To this reaction solution were added a 20 wt % aqueous solution of sodium sulfite and a saturated aqueous solution of ammonium chloride, the mixture was extracted with ethyl acetate. The organic layer was washed with a saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate, and then concentrated under reduced pressure. To the resulting solid residue was added a mixed solvent of ethyl acetate/n-hexane=1/2, the mixture was stirred. A solid was collected from this suspension by filtration, and was dried under reduced pressure to give the titled compound (4.19 g).

Provenance & Evidence