Phosphorus tribromide → 7-(Bromomethyl)-3-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)-4,5-dihydronaphtho[1,2-c]isoxazole

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Reaction Steps

To a solution of (3-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-yl)methanol (Preparation 6B, 700 mg, 1.698 mmol) in anhydrous dichloromethane (25 mL) was added phosphorous tribromide (0.240 mL, 2.55 mmol) slowly at 0° C. under nitrogen. The reaction mixture was then stirred at room temperature overnight. Next, 10 mL of ice water was added at 0° C. to quench the reaction. The organic layer was separated, washed with saturated aqueous sodium bicarbonate solution (20 mL) and filtered over CELITE®. The aqueous layer was separated, combined with the aqueous layer from before and extracted with dichloromethane (2×20 mL). The combined organic solutions were dried over sodium sulfate, filtered through a silica gel pad that was rinsed with dichloromethane, and concentrated under reduced pressure to give 7-(bromomethyl)-3-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)-4,5-dihydronaphtho[1,2-c]isoxazole (580 mg, 1.220 mmol, 71.9% yield) as a yellow solid. LC/MS M+1=477.

Provenance & Evidence