反应详情

To 7-methoxy-3-(4-propylphenyl)-4,5-dihydronaphtho[1,2-c]isoxazole (Preparation 9B, 0.35 g, 1.096 mmol) in dichloromethane (10 mL) was added boron tribromide (1.425 mL, 1.425 mmol) dropwise over a period of 3 min. at 0° C. Approximately 2 min. after the addition was complete a white solid separated out. The reaction mixture was allowed to come to room temperature over a period of 10 min. and then was stirred at room temperature for 30 min. Additional boron tribromide (2 mL) was added at room temperature and the contents were stirred at room temperature for 1.5 h. Additional boron tribromide (10 mL) was added at room temperature. The heterogeneous solution become homogenous and brown. The contents were stirred at room temperature for an additional 3 h, then cooled to 0° C. and quenched by the very slow addition of MeOH (˜5 mL). The reaction mixture was concentrated under reduced pressure and partitioned between dichloromethane (50 mL) and water (20 mL). The dichloromethane layer was dried over sodium sulfate and concentrated to yield a greenish solid. Trituration with dichloromethane (2 mL) and ether (10 mL) followed by sonication for 3 min. yielded an off-white solid which was collected by filtration and washed with ether (2×5 mL) to afford 3-(4-propylphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-ol (0.115 g). The compound had an HPLC retention time=3.80 min (condition C); LC/MS M+1=306. 1H NMR (400 MHz, MeOD) δ ppm 7.72 (dd, J=8.16, 1.38 Hz, 3H) 7.38 (d, J=8.28 Hz, 2H) 6.76-6.84 (m, 2H) 2.93-3.07 (m, 4H) 2.65-2.72 (m, 2H) 1.65-1.78 (m, 2H) 0.99 (t, 3H).

1. additionApproximately 2 min. after the addition
2. customseparated out
3. additionAdditional boron tribromide (2 mL) was added at room temperature
4. stirringthe contents were stirred at room temperature for 1.5 h
5. additionAdditional boron tribromide (10 mL) was added at room temperature
6. stirringThe contents were stirred at room temperature for an additional 3 h
7. temperaturecooled to 0° C.
8. customquenched by the very slow addition of MeOH (˜5 mL)
9. concentrationThe reaction mixture was concentrated under reduced pressure
10. custompartitioned between dichloromethane (50 mL) and water (20 mL)
11. dry with materialThe dichloromethane layer was dried over sodium sulfate
12. concentrationconcentrated
13. customto yield a greenish solid
14. customyielded an off-white solid which
15. filtrationwas collected by filtration
16. washwashed with ether (2×5 mL)