反应详情

To a stirred solution of ethyl 5-methoxybenzofuran-2-carboxylic acid (5.0 g, 26 mmol) in dichloromethane (CH2Cl2) (100 ml) at 0° C. was added boron tribromide (8.6 mL, 91 mmol) and the resulting dark solution was allowed to stir at room temperature for 2 hours. The reaction solution was poured over ice, stirred for 30 minutes and extracted with ethyl acetate (EtOAc). The organic phase was washed with water, saturated aqueous brine, dried over sodium sulfate, (Na2SO4), and concentrated in vacuo to afford 5-hydroxybenzofuran-2-carboxylic acid (4.0 g; m.p. 223°-228° C.).

1. additionThe reaction solution was poured over ice
2. stirringstirred for 30 minutes
3. extractionextracted with ethyl acetate (EtOAc)
4. washThe organic phase was washed with water, saturated aqueous brine
5. dry with materialdried over sodium sulfate, (Na2SO4),
6. concentrationconcentrated in vacuo