Synthesis, Characterization and Screening of Some Schiff Bases as Potential Antimicrobial Agents

Schiff bases derived from 4-amino antipyrene were prepared, and IR and NMR spectral analysis characterized their structure. The Schiff bases produced were (1) 4-((4-chlorobenzylidine)amino)-1,5-dimethyl-1H-pyrazole-3(2H)-one. [SBS-1], (2) 4-((4-hydroxybenzylidine)amino)-1,5-dimethyl-1H-pyrazole-3(2H)-one. [SBS-2], (3)1,5-dimethyl-2phenyl-4-((3- phenylallylidine)amino) -1H-pyrazole-3(2H)-one. [SBS-3], (4)4-((4-hydroxy-3-methoxybenzylidine)amino)-1,5- dimethyl-1H-pyrazole-3(2H)-one. [SBS-4], (5) 4-(benzylidineamino)-1,5 -dimethyl-1H-pyrazole-3(2H)-one. [SBS-5], (6) 4-((furan-2-ylmethelene)amino)-1,5-dimethyl-1H-pyrazole-3(2H)-one. [SBS-6] and (7) 4-((4-methoxybenzylidine)amino)-1,5- dimethyl-1H-pyrazole-3(2H)-one. [SBS-7]. The antibacterial activity was studied against S. subfava NCIM 2178, B. megaterium ATCC 9885, P. pseudoalcaligenes ATCC 17440, P. vulgaris NCTC 8313, C. freundii ATCC 10787 and E. aerogenes ATCC 13048. The antibacterial activity was done using Agar Ditch method. The antibacterial activity was evaluated in two polar solvents DMSO and DMF. A differential effect of the compounds extracted in a particular solvent (DMSO/DMF) inhibited different bacteria to a different level. It supports the earlier conclusion that antibacterial activity is dependent on molecular structure of the compound, solvent used and the bacterial strain under consideration. However, from the present results, it appears that cinnamaldehyde as side chain with 4-amino antipyrene as central ligand and DMF as a solvent to be best in inhibiting the studied bacterial strains.