U.S. Pat. No. 3,896,131 describes a broad class of 6,7-dihydro-5-methyl-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acids as antimicrobial agents. The patent specifically discloses several compounds substituted by halogen and/or methyl on the benzo ring. The compound 6,7-dihydro-9-fluoro-5-methyl-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxyli c acid (now known as flumequine) which is disclosed in the aforementioned patent has received the most attention for its antimicrobial activity. It has now been found that the corresponding novel 8-methyl-9-fluoro compound exhibits greatly enhanced antimicrobial activity.
U.S. Pat. No. 4,301,289 describes the compounds 6-fluoroquinaldine, 6-fluoro-1,2,3,4-tetrahydroquinaldine, and dialkyl 2-[N-(6-fluoro-1,2,3,4-tetrahydroquinaldinyl]methylenemalonates.