THE SYNTHESIS AND ANTIBACTERIAL ACTIVITIES OF QUINOLONES CONTAINING 5-MEMBERED AND 6-MEMBERED HETEROCYCLIC SUBSTITUENTS AT THE 7-POSITION

A series of 6-fluoro-7-substituted-l-ethyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acids were prepared. The substituents at the 7-position included five- and six-membered heterocyclic rings such as oxazoline and oxazine as well as five-membered heteroaromatic rings such as oxazoles and imidazoles. The structure-activity relationships (SAR) of these compounds indicated that oxazole substituent containing a 2-methyl group had the greatest in vitro potency. The compounds showed greater in vitro antibacterial activity against Gram-positive organisms than against Gram-negative organisms. © 1990, American Chemical Society. All rights reserved.