Nitroquinolones with broad-spectrum antimycobacterial activity in vitro

During search on quinolonecarboxylic acids we used a facile, convenient two - or three-step procedure to synthesize new quinolone analogs, bearing at t he C-7 position alkylamino substituents, and at the C-6 position a fluorine or alternatively a nitro group. The new derivatives were tested against bo th Gram-positive and Gram-negative bacteria and against a number of differe nt mycobacteria. In vitro assay's showed 1-tert-butyl-7-tert-butylamino-6-n itro-1,4-dihydro-4-quinolone-3-carboxylic acid to be a potent inhibitor of Streptococcus and Staphylococcus with potencies superior to those of ofloxa cin and ciprofloxacin, used as reference drugs. Some 6-nitroquinolones were found to exert good inhibiting activities against Mycobacterium tuberculos is and various atypical mycobacteria, whereas the 6-fluoro counterparts sho wed poor or no activity against this bacterium. (C) 1999 Elsevier Science L td. All rights reserved.