The Synthesis, Structure-Activity, and Structure-Side Effect Relationships of a Series of 8-Alkoxy- and 5-Amino-8-alkoxyquinolone Antibacterial Agents

Article abstract of DOI:10.1021/jm00022a013

A series of 1-cyclopropyl-6-fluoro-8-alkoxy (8-methoxy and 8-ethoxy)-quinoline-3-carboxylic acids and 1-cyclopropyl-5-amino-6-fluoro-8-alkoxyquinoline-3-carboxylic acids has been prepared and evaluated for antibacterial activity.In addition, they were also compared to quinolones with classic substitution at C₈ (H, F, Cl) and the naphthyridine nucleus in a phototoxicity and mammalian cell cytotoxiciry assay.The series of 8-methoxyquinolones had antibacterial activity against Gram-positive, Gram-negative, and anaerobic bacteria equivalent to that most active 8-substituted compounds (8-F and 8-Cl).There was also a concomitant reduction in several of the potential side effects (i.e., phototoxicity and clonogenicity) compared to the most active quinolones with classic substitution at C-8.The 8-ethoxy derivatives had an even better safety profile but were significantly less active (2-3 dilutions) in the antibacterial assay.