Structure-activity relationships of the quinolone antibacterials against mycobacteria: effect of structural changes at N-1 and C-7.
The re-emergence of tuberculosis infections which are resistant to conventional drug therapy has demonstrated the need for alternative chemotherapy against Mycobacterium tuberculosis. As part of a study to optimize the quinolone antibacterials against M. tuberculosis, we have prepared a series of N-1- and C-7-substituted quinolones to examine specific structure-activity relationships between modifications of the quinolone at these two positions and activity against mycobacteria. The compounds, synthesized by literature procedures, were evaluated for activity against Mycobacterium fortuitum and Mycobacterium smegmatis as well as Gram-negative and Gram-positive bacteria. The activity of the compounds against M. fortuitum was used as a barometer of M. tuberculosis activity. The results demonstrate that (i) the activity against mycobacteria was related more to antibacterial activity than to changes in the lipophilicity of the compounds, (ii) the antimycobacterial activity imparted by the N-1 substituent was in the order tert-butyl > or = cyclopropyl > 2,4-difluorophenyl > ethyl approximately cyclobutyl > isopropyl, and (iii) substitution with either piperazine or pyrrolidine heterocycles at C-7 afforded similar activity against mycobacteria.
Renau
T E
TE
Parke-Davis Pharmaceutical Research, Division of Warner-Lambert Company, Ann Arbor, Michigan 48105, USA.
Sanchez
J P
JP
Gage
J W
JW
Dever
J A
JA
Shapiro
M A
MA
Gracheck
S J
SJ
Domagala
J M
JM
D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D009161:Mycobacterium / Q000187:drug effects*; D013055:Spectrophotometry, Infrared; D013329:Structure-Activity Relationship
D000900:Anti-Bacterial Agents