B(Br)(Br)Br.C[O:6][C:7]1[CH:12]=[CH:11][C:10]([N:13]2[C:17]([C:18]3[CH:23]=[CH:22][C:21]([S:24]([CH3:27])(=[O:26])=[O:25])=[CH:20][CH:19]=3)=[CH:16][C:15]([C:28]([F:31])([F:30])[F:29])=[N:14]2)=[CH:9][CH:8]=1>ClCCl>[OH:6][C:7]1[CH:8]=[CH:9][C:10]([N:13]2[C:17]([C:18]3[CH:19]=[CH:20][C:21]([S:24]([CH3:27])(=[O:26])=[O:25])=[CH:22][CH:23]=3)=[CH:16][C:15]([C:28]([F:29])([F:30])[F:31])=[N:14]2)=[CH:11][CH:12]=1Boron tribromide (1M in dichloromethane; 11 ml) was added to an ice-cooled solution of 1-(4-methoxyphenyl)-5-[4-(methylsulfonyl)phenyl]-3-(trifluoromethyl)pyrazole (1.4 g) in dichloromethane (30 ml). The mixture was stirred at 5° C. for 2 hours and concentrated in vacuo. The residue was triturated in dilute hydrochloric acid. The obtained powder was recrystallized from ethanol to give colorless crystals of 1-(4-hydroxyphenyl)-5-[4-(methylsulfonyl)phenyl]-3-(trifluoromethyl)pyrazole (0.91 g).
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