Synthesis, characterization and biological activity of Schiff bases derived from metronidazole

A series of novel Schiff bases; compounds 3a-j were prepared by reacting 1-(2-aminoethyl)-2-methyl-5-nitroimidazole dihydrochloride monohydrate (1) with different aldehydes. The structures of these compounds were confirmed through different spectroscopic methods such as H-1-NMR, C-13-NMR and mass spectrometry and also by elemental analyses. The prepared compounds were evaluated in vitro for their antigiardial, antibacterial and antifungal activities. Compounds 3h, 3b and 3d showed remarkable antigiardial activities and were found to be more active than metronidazole with IC50 of 0.83, 1.36 and 1.83 mu M, respectively. Other compounds also exhibited antigiardial activity and were as good as or even more potent than metronidazole. Some of the newly synthesized Schiff bases exhibited more antifungal activities than the parent drug. In addition, a few of the prepared compounds exhibited modest antibacterial activity but were not as active as metronidazole.