THE SYNTHESIS OF A SERIES OF 7-AMINO-1-CYCLOPROPYL-8-FLUORO-1,4-DIHYDRO-4-OXO-1,6-NAPHTHYRIDINE-3-CARBOXYLIC ACIDS AS POTENTIAL ANTIBACTERIAL AGENTS

A series of 7-amino-1-cyclopropyl-1,4-dihydro-8-fluoro-4-oxo-1,6-naphthyridine-3-carboxyl ic acids has been prepared and evaluated for antibacterial activity. These compounds were prepared by the displacement of the chloro substituent from 7-chloro-1-cyclopropyl-1,4-dihydro-8-fluoro-4-oxo-1,6-naphthyridine-3-carboxy lic acid employing the requisite nitrogen nucleophile to produce the title compounds. The naphthyridine acid was synthesized in ten steps from ethyl 2,4-dihydroxy-3-nitro-5-pyridinecarboxylate. The key step in the sequence was a Schiemann reaction carried out using the hexafluorophosphate salt of the diazonium ion derived from ethyl 3-amino-2,4-dichloro-5-pyridinecarboxylate.