| 摘要 |
Starting from ethyl 3-(2,6-dichloro-5-fluoropyridin-3-yl)-3-oxo-propanoate (1), the present invention provides highly pure 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid (5) in one-pot four steps using a single solvent. |
