反应详情

4-(3-Amino-2-methoxy-phenyl)-furan-2-carboxylic acid 22d (325 mg, 1.4 mmol) was dissolved in 5 mL of dichloromethane followed by dropwise addition of boron tribromide (2.8 mL, 5.6 mmol). The mixture was reacted at room temperature for 4.5 hours. 5 mL of methanol was added and then the mixture was concentrated under reduced pressure. The residue was diluted with 10 mL of ethyl acetate and stirred for 0.5 hours. The mixture was filtered and the filter cake was dried to obtain the title compound 4-(3-amino-2-hydroxy-phenyl)-furan-2-carboxylic acid hydrobromide 22e (174 mg, yield 57.1%) as a grey solid.

1. customThe mixture was reacted at room temperature for 4.5 hours
2. concentrationthe mixture was concentrated under reduced pressure
3. additionThe residue was diluted with 10 mL of ethyl acetate
4. filtrationThe mixture was filtered
5. customthe filter cake was dried