Novel 5-amino-6-methylquinolone antibacterials: A new class of non-6-fluoroquinolones

A novel 5-amino-6-methylquinoline carboxylic acid was synthesized from 2,3,4-trifluoro aniline in 12 steps and coupled with various types of amines to furnish new quinolone antibacterial agents. Depending on the structure of amine, some of quinolones showed comparable activity to ciprofloxacin or better Gram positive activity than ciprofloxacin, demonstrating that the C6 fluorine atom is not a necessary requirement for good antibacterial potency.