反应详情

0.5 ml of 48% hydrobromic acid and 1 ml of glacial acetic acid were added to 0.2 gm (0.55 millimols) of 4-methoxy-2-methyl-N-(5-methyl-2-thiazolyl)-2H-1,2-benzothiazine-3-caboxamide-1,1-dioxide. After standing for 24 hours, the reaction mixture was heated for two hours on a water bath and was subsequently evaporated in vacuo to dryness. The residue was dissolved in methylene chloride, and the solution was washed with water. After drying and evaporating of the organic phase, 4-hydroxy-2-methyl-N-(5-methyl-2-thiazolyl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide was obtained with a yield of 0.1 gm (52% of theory).

1. temperaturethe reaction mixture was heated for two hours on a water bath
2. customwas subsequently evaporated in vacuo to dryness
3. dissolutionThe residue was dissolved in methylene chloride
4. washthe solution was washed with water
5. customAfter drying
6. customevaporating of the organic phase