7-Methoxy-3-(3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)-4,5-dihydronaphtho[1,2-c]isoxazole → 3-(3-Phenyl-4-(trifluoromethyl)isoxazol-5-yl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-ol

Participants

Reaction Steps

To 7-methoxy-3-(3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)-4,5-dihydronaphtho[1,2-c]isoxazole (Preparation 8A, 0.125 g, 0.303 mmol) in dichloromethane (4 mL) was added borontribromide (1.0 M in dichloromethane, 3.03 mL, 3.03 mmol) at 0° C. over a period of 3 min. The contents were allowed to come to room temperature over a period of 15 min. and stirred at room temperature for 1 h. Additional borontribromide (4 mL) was added at room temperature over a period of 2 min. and the reaction was stirred for 3 h. The reaction mixture was concentrated and kept on the high vacuum pump for 10 min. Dichloromethane (5 mL) was added followed by 3 mL of borontribromide at room temperature. The contents were stirred at room temperature for 60 h. The reaction mixture was cooled to 0° C. and quenched by the slow addition of methanol (˜0 mL). The contents were stirred for 10 min. and concentrated under reduced pressure. The resulting residue was partitioned between dichloromethane (25 mL) and water (10 mL). The dichloromethane layer was washed with brine (20 mL), dried over sodium sulfate and concentrated. The resulting solid was triturated with ethyl acetate (5 mL), collected by filtration, washed with ethyl acetate (2×3 mL) and dried to yield 3-(3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-ol (0.050 g, 0.119 mmol, 39.3% yield) as a white solid. The compound had an HPLC retention time=3.77 min (condition C); LC/MS M+1=399.

Provenance & Evidence