反应详情

A mixture of methyl 7-methoxy-1,1-dioxo-2,3-dihydro-1-benzothiepine-4-carboxylate (300 mg), 48% hydrobromic acid (3 ml) and acetic acid (3 ml) was heated at reflux for 4 hours. After concentration under reduced pressure, 48% hydrobromic acid (3 ml) and acetic acid (3 ml) were further added to the reaction mixture, which was heated at reflux for 8 hours. After concentration under reduced pressure, the precipitated crystals were collected by filtration. The crystals were washed with diisopropyl ether to obtain 7-hydroxy-1,1-dioxo-2,3-dihydro-1-benzothiepine-4-carboxylic acid (224 mg) as light yellow crystals.

1. temperaturewas heated
2. temperatureat reflux for 4 hours
3. concentrationAfter concentration under reduced pressure, 48% hydrobromic acid (3 ml) and acetic acid (3 ml)
4. additionwere further added to the reaction mixture, which
5. temperaturewas heated
6. temperatureat reflux for 8 hours
7. concentrationAfter concentration under reduced pressure
8. filtrationthe precipitated crystals were collected by filtration
9. washThe crystals were washed with diisopropyl ether