Water → 1-benzyl-4-bromo-5-(3,4-dihydro-2H-1-benzopyran-6-yl)-3-(trifluoromethyl)-1H-pyrazole

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Reaction Steps

A solution 1-benzyl-5-(3,4-dihydro-2H-1-benzopyran-6-yl)-3-(trifluoromethyl)-1H-pyrazole (49c) (260 mg, 0.73 mmol) and N-bromosuccinimide (157 mg, 0.88 mmol) in acetonitrile (5 mL) was refluxed for 45 minutes. Water (5 mL) was added, and the aqueous layer was extracted with dichloromethane (2×5 mL). The combined organics layers were dried over sodium sulfate and concentrated in vacuo. The residue was purified by preparative TLC (cyclohexane/ethyl acetate 100/0 to 90/10) to provide the 1-benzyl-4-bromo-5-(3,4-dihydro-2H-1-benzopyran-6-yl)-3-(trifluoromethyl)-1H-pyrazole (49d) (200 mg, 0.46 mmol, 63%).

Provenance & Evidence