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Synthesis of4-aminoantipyrine Schiff bases and their antimicrobial activities
Various compounds of 4-aminoantipyrine Schiff bases (M1-M12) were synthesized via a condensation reaction of 4-aminoantipyrine with different benzaldehydes through a conventional method of refluxing the mixture for 3-4 h.The synthesized Schiffbases were characterized bY using elemental analyses,FT-IR,UV-Vis,Mass,1H and 13C NMR spectroscopy.The antimicrobial activity of the synthesized Schiff bases was investigated against 12 bacterial strains (Mycobacterium smegmatis,Bacillus cereus,Bacillus subtilis,Enterococcus faecalis,Staphylococcus epidermidis,Klebsiella pneumonia,Escherichia coli,Enterobacter cloacae,Klebsiella oxytoca,Proteus vulgaris,Enterobacter aerogenes,and Pseudomonas aeruginosa),and antifungal activities were tested against seven fungal strains (Aspergillus flavus,Aspergillus carbonarious,Aspergillus parasiticus,Aspergillus fumigatus,Aspergillus niger,Fusarium verticillioides and Fusarium proliferatum).The antimicrobial activities of the synthesized compounds were compared with standard streptomycin and nalidixic acid.The results obtained from antibacterial assay indicated that M1-M12 inhibited potential growth of Proteus vulgaris with minimum inhibitory concentrations (MICs) ranging from 15.6-250 μg/mL compared with the standard nalidixic acid with an MIC of 500 μg/mL.Moreover,we could conclude that most of the tested compounds experienced mild to low activities at 15.6 μg/mL.Their activities could be attributed to their low concentration s.The antifungal analysis showed that the tested fungi were not sensitive to the prepared Schiffbases at the prepared concentration of 500 tg/mL.Therefore,we recommended further analysis on both cytotoxicity and minimum bactericidal concentration (MBC) to ascertain their potential effects against human cells.
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Synthesis,characterization and biological activities of Schiff bases derived from 2-hydroxy-3-nitrobenzaldehyde
Four novel Schiff bases were synthesized by the condensation reaction of 2-hydroxyl-3-nitrobenzaldehyde with either benzothiazoles or benzimidazolamines.The compounds 1-4 were characterized by spectroscopic and analytical methods.The crystal structures of 6-methoxy-1,3-benzothiazol-2-amine and compound 2 are reported only.The 6-methoxy-1,3-benzothiazol-2-amine was found to crystallize in the orthorhombic crystal system in the space group Pbca,having eight molecules in the unit cell,while compound 2 was found to crystallize in the monoclinic crystal system in the space group P21/c.The biological activities of these compounds were investigated by evaluating their antibacterial,antifungal,antimalarial,anti-HIV and anti-trypanosomiasis activities.These compounds displayed very interesting antibacterial,antifungal,antimalarial,anti-trypanosomiasis,anti-HIV and low cytotoxicity activity against HeLa cells.