No abstract

A number of 7-piperazinylquinolones carrying a functionalized 2-(furan-3-yl)ethyl moiety attached to the piperazine ring have been synthesized and evaluated as antibacterial agents against a panel of Gram-positive and Gram-negative bacteria. Most of the synthesized compounds exhibited significant antibacterial activity, and this activity can be modulated through the nature of the functionality on ethyl spacer attached to piperazine ring and the type of side chain present at the N-1 position of quinolone ring.

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.

As a part of continuing search for potential antibacterial agents in the quinolones field, we have synthesized novel quinolone agents bearing N-[2-(thiophen-3-yl)ethyl] piperazinyl moiety in the 7-position of the quinolone ring. In vitro antibacterial evaluation of the target compounds showed that N-[2-(thiophen-3-yl)ethyl] group attached to piperazine ring served as promising C-7 substituent for piperazinyl quinolone antibacterials. Among these derivatives, ciprofloxacin analogues, containing N-[2-(thiophen-3-yl)-2-hydroxyiminoethyl] or N-[2-(thio-phen-3-yl)-2-methoxyiminoethyl] residue provided a high inhibition against all the tested Gram-positive organisms including methicillin-resistant Staphylococcus aureus comparable or superior with respect to the reference drugs norfloxacin and ciprofloxacin.

Organic salts of cobalt were synthesized in the presence of amine, ethanol, and ethyl methyl ketoxime and were used as drier for alkyd resin. Considering the drying time of alkyd resin containing synthesized compound showed that amines, as electron releasing groups (ERG), increased the oxidizing activity of drier and shortened drying time about an hour, whereas ethyl methyl ketoxime delayed the drying of resin 2 hours. Two methods of synthesis, including solution and precipitation processes of synthesis, were compared in terms of convenience, cost, and environmental aspects.