反应详情

To a solution of 20 parts of 2,3-dihydro-3-oxo-5H-pyrido[3,4-b][1,4]benzothiazine-4-carbonitrile in 1575 parts of glacial acetic acid is added a solution of 34 parts of bromine in 320 parts of carbon tetrachloride. The resultant mixture is heated at the boiling point under reflux for 23/4 hours, then chilled. The precipitate which forms is filtered off and recrystallized from N,N-dimethylformamide to give 8-bromo-2,3-dihydro-3-oxo-5H-pyrido[3,4-b][1,4]benzothiazine-4-carbonitrile melting above 305°.

1. temperatureunder reflux for 23/4 hours
2. temperaturechilled
3. filtrationThe precipitate which forms is filtered off
4. customrecrystallized from N,N-dimethylformamide