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

Abstract

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. pseudoalcaligenes ATCC 17440, P. vulgaris NCTC 8313, C. freundii ATCC 10787 E. aerogenes ATCC 13048, S. subfava 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) 4-(4-methoxybenzylideneamino) -1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one [VY4]?; (5) 2-methoxy-4-[(4-methoxyphenylimino) methyl ]phenol [VY5]; (6) 4-[(2,4-dimethylphenylimino) methyl]-2-methoxyphenol [VY6]); (7) 2-methoxy-4-(naphthalene-1-yliminomethyl) phenol [VY7]?and (8) 4-[(4-hydroxy-3-methoxybenzylidene)amino]-N-(5-methylisoxazol 3-yl)benzenesulfonamide [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.