反应详情

A solution of 4-chloro-6-methoxy-1-methylphthalazine (4) (2.08 g, 9.99 mmol), 1.0 M boron tribromide (17.00 mmol) in dichloromethane (17 mL), and dichloromethane (50 mL) is stirred under argon at −78° C. for 10 min, room temperature for 38 h, and at reflux for 3 h. The mixture is cooled to room temperature, diluted with sat. NaHCO3 (130 mL), and extracted with ethyl acetate (150 mL and 4×60 mL). The extract is washed (water and brine) and dried. After solvent removal at reduced pressure, the remaining solid is washed with dichloromethane to give 650 mg (70%) of 5 as a yellow solid, mp >260° C. IR 3351, 2938, 1610, 1223 cm−1; 1H NMR (DMSO-d6) δ 2.84 (s, 3H, CH3), 7.44 (d, J=8.7 Hz, 1H, 8-PhthH), 7.59 (dd, J=9.0, 2.4 Hz, 1H, 6-PhthH), 8.19 (d, J=9.0 Hz, 1H, 5-PhthH), 11.27 ppm (s, 1H, OH).

1. temperatureat reflux for 3 h
2. extractionextracted with ethyl acetate (150 mL and 4×60 mL)
3. washThe extract is washed (water and brine)
4. customdried
5. customAfter solvent removal at reduced pressure
6. washthe remaining solid is washed with dichloromethane