反应详情

A mixture of (S)-2,4-diethyl-7-methoxycarbonyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine (1.90 g) in concentrated hydrochloric acid (40 ml) was stirred under reflux for a day. The concentrated hydrochloric acid was distilled off under reduced pressure to give (S)-2,4-diethyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-7-carboxylic acid (1.47 g).

1. temperatureunder reflux for a day
2. distillationThe concentrated hydrochloric acid was distilled off under reduced pressure