反应详情

Compound 46 (5 g, 21.7 mmol) was dissolved in dichloromethane followed by the dropwise addition of boron tribromide (1M solution in dichloromethane, 84 ml, 84 mmol) at 0° C. The reaction mixture was left at 4° C. overnight. Water (100 ml) was added carefully to destroy excess boron tribromide. The solid precipitation was filtered off to yield brownish pure compound. Yield=4.15 g. (94%). 1H NMR (dmso-d6): 9.29 (s, 1H), 9.20 (s, 1H), 8.77 (s, 1H), 7.46 (d, 1H, J=3.02 Hz), 6.65 (d, 1H, J=8.89 Hz), 6.33 (dd, 1H, J=8.95 and 2.98 Hz), 4.35 (s, 2H). 13C NMR (dmso-d6): 165.0, 150.3, 150.2, 140.2, 126.6, 116.2, 111.6, 44.1. ES-HRMS [M+H]+202.0271. Calcd for (C8H9NO3):202.0278.

1. customto destroy excess boron tribromide
2. customThe solid precipitation
3. filtrationwas filtered off
4. customto yield brownish pure compound