Synthesis and In‐Vitro Antibacterial Activity of 5‐Substituted 1‐Methyl‐4‐nitro‐1H‐imidazoles

Abstract

A series of 5-substituted 1-methyl-4-nitro-1H-imidazole derivatives were synthesized and evaluated for in-vitro antibacterial activity against a panel of microorganisms including Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli, Klebsiella pneumonia, Enterobacter aerogenes, and Helicobacter pylori using conventional agar dilution method. Among the test compounds, 1-methyl-4-nitro-5-(phenylsulfonyl)-1H-imidazole was the most potent against Gram-positive bacteria, with a MIC value of < or =8 microg/mL. All compounds showed no significant activity against Gram-negative bacteria at concentrations < or =64 microg/mL. The MIC values against 15 clinical isolates of H. pylori indicated that compounds 10 and 11 were the most active compounds in this series in terms of inhibiting the growth of H. pylori (MIC = 2 microg/mL). It was also demonstrated that their corresponding activities were four times larger than that of metronidazole.

5‐Nitroimidazole‐based 1,3,4‐Thiadiazoles: Heterocyclic Analogs of Metronidazole as Anti‐Helicobacter pylori Agents

“…Following incubation for 3 to 5 days at 378C, the inhibition zone around each disc was recorded. All tests were performed in triplicate and the antibacterial activity was expressed as the mean of inhibition diameters (in mm) produced by title compounds [9]. This work was supported by a grant from the Tehran University of Medical Sciences, Tehran, Iran.…”

“…Strains displaying primary resistance to metronidazole and clarithromycin have been reported with increasing frequency throughout the world and resistance is likely to become an increasingly important problem in the clinical management of H. pylori infections [8]. Thus, the discovery of novel and potent antibacterial agents is the best way to overcome bacterial resistance and develop effective therapies [9]. Hence, our research efforts are directed toward the discovery of new chemical entities that are effective as anti-Helicobacter pylori agents and the optimization of their structures.…”

“…Hence, our research efforts are directed toward the discovery of new chemical entities that are effective as anti-Helicobacter pylori agents and the optimization of their structures. During recent years, there have been intense investigations of different classes of 1,3,4-thiadiazole-and nitroimidazole-containing compounds, many of which are known to possess biological properties such as antituberculosis and anti-H. pylori activities [9][10][11][12]. In continuation of our ongoing research work on nitroheterocyclic derivatives [13], herein, we describe the synthesis and in-vitro antibacterial activity of new 5-nitroimidazole-based 1,3,4-thiadiazoles 6ah and 7 against Helicobacter pylori.…”

Synthesis and In Vitro Antibacterial Activity of New 2‐(1‐Methyl‐4‐nitro‐1H‐imidazol‐5‐ylsulfonyl)‐1,3,4‐thiadiazoles

“…Moreover, the use of nitroheterocycles as antiviral, anticancer and radio sensitizing agents is well established [4][5][6][7][8][9][10] . In our previous studies, some new compounds containing 5-nitroheterocycles and 1,3,4-thiadiazole with different substituents at the C 2 -position of the thiadiazole ring were synthesized and evaluated for activity against several bacterial species and H. pylori [11][12][13] . In continuation to our ongoing research work on new nitroheterocyclic derivatives, herein, we describe the synthesis and in vitro antibacterial activity of new 5-sulfonyl-1-methyl-4-nitro-1Himidazoles (6a-c) against a panel of gram-positive and gram-negative bacteria.…”

Synthesis and biological activity of 5-nitrofuran-containing (1,3,4-thiadiazol-2-yl)piperazine moieties as a new type of anti-Helicobacter pylori heterocycles

“…[7][8][9][10][11] With this point of view and the potent biological activity of 2-(5--nitrofuran-2-yl)-1,3,4-thiadiazoles, the synthetic strategy is now focused on the introduction of a cyclic amine functionality at the C-2 position of the 1,3,4-thiadiazole ring. [7][8][9][10][11] With this point of view and the potent biological activity of 2-(5--nitrofuran-2-yl)-1,3,4-thiadiazoles, the synthetic strategy is now focused on the introduction of a cyclic amine functionality at the C-2 position of the 1,3,4-thiadiazole ring.…”