Synthesis, structural determination and antibacterial activity of compounds derived from vanillin and 4-aminoantipyrine

Schiff bases derived from 4-aminoantipyrine and vanillin were evaluated for their potential as antibacterial agents against some Gram positive and Gram negative bacterial strains. The antibacterial activity was studied against P pseudoalealigenes ATCC 17440, P vulgaris NCTC 8313, C freundii ATCC 10787, E. aerogenes ATCC 13048, S subfam NCIM 2178 and B. megaterium ATCC 9885. The determination of the antibacterial activity was done using the Agar Ditsh method. The Schiff bases produced were: (1) 4-(4-hydroxy-3-methoxybenzylideneamino 1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one [VV1]; (2) 4-(benzylideneamino)-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one[VY2]); (3)4-[(furan-3-ylmethylene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one[VY3]; (4) 444-mcthoxybenzylideneamino 1,5-dimethyl-2-phenyl-1,2-dhydro-pyrazol-3-one[VY4]; (5) 2-methoxy-4-[(4-methoxyphenylimino)methyl]phenol [VY5]; (6) 4-[(2,4-dimethylphenylimino)methyl]-2-methoxyphenol [VY6]); (7) 2-methoxy4-(naphthalene-1-yliminomethyl)phenol [VY7] and (8) 4-[(4-hydroxy-3-methoxybenzylidene)amino]-N-(5-methylisoxazol-3-yl)benzenesuifonamide [VY8]. The antibacterial activity was evaluated in two polar solvents, DMSO and DMF. The Schiff bases derived from vanillin as the central molecule with 2,4-dimethylaniline and sulphamethoxazole as the side chain in DMSO effectively inhibited the investigated bacteria and appear to be promising antimicrobial agents.