Synthesis and antibacterial activity of novel 7-haloanilino-8-nitrofluoroquinolone derivatives

Abstract

The synthesis of new 7-(halophenylamino)-1-cyclopropyl-6-fluoro-8-nitro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid derivatives is described. Substitution of quinolonic compound 1a with chloro and fluoro aniline derivatives at position 7 produced target compounds 2-9 with relatively low yields. Alternatively, the product of correspondent carboxylate ester 1b subsequent with acid hydrolysis produced satisfactory yield. The prepared targets have shown interesting antibacterial properties against standard and resistant gram-positive strains. In particular, 2-chloro and 3-chloro aniline derivatives (3 and 4) depict MIC values of 6.7 and 0.9 lg/ml, respectively against standard S. aureous. Both compounds showed good activity against resistant strains of S. aureous.

Synthesis of 1,2,3-Triazolo[4,5-h]quinolone Derivatives with Novel Anti-Microbial Properties against Metronidazole Resistant Helicobacter pylori

“…Evidently, most of our derivatives are lipophilic compound and have shown the reasonable inhibitory activity against H. pylori [ 29 ]. These findings were emphasized previously by our group: highly lipophilic fluoroquinolone ligands improve antibacterial activity against Gram positive bacteria in particular, and to some extent against Gram negative bacteria [ 26 , 27 , 28 ]. Within the same vein, our group has emphasized that Gram negative activity was boosted through C-7 and C-8 hydrogen bond network of fluoroquinolone systems as represent by compounds of series 4 .…”

“…In previous work [ 26 , 27 , 28 , 29 ], we established that the activity of these FQs mendacities mainly within the 4-oxo-pyridine-3-carboxylic acid system present in all compounds prepared ( 3 – 5 ). Losing the free COOH group in compounds 2 – 5 reduced the inhibitory activity against H. pylori significantly [ 29 ].…”

“…It is worth mentioning that our compounds are more active than metronidazole on the resistant strains. This activity might be linked to their lipophilicity [ 26 , 27 ].…”

“…So far, low level of resistance against fluoroquinolones among H. pylori clinical strains is reported [ 24 , 25 ]. In a previous work, the biological activities of a group of 8-nitro 7-substituted fluoroquinolone derivatives have been evaluated and strong antibacterial activity against Escherichia coli and Staphylococcus aureus was observed [ 26 , 27 ]. In general, the synthesis of novel 8-nitro 7-substituted fluoroquinolone derivatives was evaluated for biological activity.…”

Synthesis of New Nitrofluoroquinolone Derivatives with Novel Anti-Microbial Properties against Metronidazole Resistant H. pylori

“…However, a low level of resistance against fluoroquinolones among H. pylori clinical strains has been reported [ 15 , 16 ]. In a previous work, the biological activities of a group of 8-nitrofluoroquinolone derivatives have been evaluated, and strong antibacterial effect against Escherichia coli and Staphylococcus aureus was observed [ 17 , 18 ].…”