反应详情

A mixture of (S)-2-ethyl-7-methoxycarbonyl-4-(2-propyl)-3-oxo-3,4-dihydro-2H-1,4-benzoxazine (0.85 g) in concentrated hydrochloric acid (20 ml) was stirred under reflux for a day. The concentrated hydrochloric acid was distilled off under reduced pressure. Water was added to the residue and extraction with ethyl acetate was conducted. The extract was washed with water and then the solvent was distilled off under reduced pressure to give (S)-2-ethyl-4-(2-propyl)-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-7-carboxylic acid (0.70 g).

1. temperatureunder reflux for a day
2. distillationThe concentrated hydrochloric acid was distilled off under reduced pressure
3. additionWater was added to the residue and extraction with ethyl acetate
4. washThe extract was washed with water
5. distillationthe solvent was distilled off under reduced pressure