反应详情

温度

-78 °C

To compound 24.1 (160 mg, 0.25 mmol) in CH2Cl2 (10 mL) at −78° C. was added 1M solution of boron trichloride in CH2Cl2 dropwise over 5 minutes and the solution stirred at −78° C. for 2.5 h and then at −25° C. for 3 hr. To this mixture was added 25 mL of 1:1 v/v CH2Cl2:MeOH and the solution stirred at −15° C. for 30 minutes. The mixture was brought to room temperature and the solvent was evaporated under reduced pressure. The residue was co-evaporated with MeOH (5×10 mL) and a 10 mL MeOH solution was neutralized with NH4OH and evaporated again. The residue was adsorbed on 2 g silica gel and loaded on a silica column and eluted successively with 50:1,20:1 and 15:1 CH2Cl2:MeOH. Fractions eluting at 20:1 and 15:1 were collected, Pooling of fraction and evaporation gave 16 mg product 24.2. 1H NMR (DMSO-d6) δ 8.10 (s, 1H), 7.51 (s, 1H), 7.30 (t, 1H), 6.61 (d, J 9 Hz, 1H), 6.11 (s, 1H), 5.71 (dt, J 6, 12 Hz, 1H), 5.08 (m, 3H), 3.86 (m, 5H), 3.78 (m, 1H), 0.72 (s, 31).

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