反应详情

A mixture of ethyl 6-ethoxy-4-hydroxy-7-methyl-1,8-naphthyridine-3-carboxylate (10.0 g), 5M sodium hydroxide solution (200 ml), IMS (64 ml) and water (64 ml) was boiled under reflux for 2 hours. The mixture was cooled to ambient temperature and then filtered. The residue was dissolved in water, acidified to pH5 with glacial acetic acid and filtered. The residue was triturated with hot IMS, cooled and filtered to give 6-ethoxy-4-hydroxy-7-methyl-1,8-naphthyridine-3-carboxylic acid, m.p. 259°-261° C.

1. temperatureunder reflux for 2 hours
2. filtrationfiltered
3. dissolutionThe residue was dissolved in water
4. filtrationfiltered
5. customThe residue was triturated with hot IMS
6. temperaturecooled
7. filtrationfiltered