反应详情

To a stirred mixture of the 5-amino-2,4-dibromophenol prepared in example 3 (13 g, 49 mmol), acetic acid (65 mL) and HCl (65 mL) was added crotonaldehyde and the resultant mixture was heated at reflux for 1.5 h under argon. HBr (65 mL) and aniline (13 mL) were added and the mixture was refluxed for 5 h. After cooling, the reaction mixture was neutralized by adding of NaHCO3 (˜180 g) and then extracted with EtOAc. The organic extract was dried (MgSO4) and concentrated in vacuo to give a black solid (22 g). The crude product was purified by column chromatography (eluents: CH2Cl2-MeOH 98:2). Yield 5 g (49%) brown-white solid. Rf=0.43 (CH2Cl2-MeOH 9:1).

1. temperatureat reflux for 1.5 h under argon. HBr (65 mL)
2. temperaturethe mixture was refluxed for 5 h
3. temperatureAfter cooling
4. extractionextracted with EtOAc
5. extractionThe organic extract
6. dry with materialwas dried (MgSO4)
7. concentrationconcentrated in vacuo