Synthesis and Antibacterial Evaluation of (E)-5-Arylidene-6-Methyl-4,5-Dihydropyridazin-3(2)-Thione Derivatives

Some(E)-5-arylidene-6-methyl-4,5-dihydropyridazin-3(2H)-thione derivatives (5a-5f) were synthesized and evaluated as antimicrobial agents against Gram positive bacteria Staphylococcus aureus, Bacillus subtilis, and Gram negative bacteria Escherichia coli, and Pseudomonas aeruginosa strains. All the title compounds were characterized by their physical (TLC and M. P.), spectral (IR, ¹H NMR) and mass spectroscopy (MS) data. Test results show that compounds 5b and 5e were found to be most effective antibacterial agents against both Gram positive and Gram negative bacterial strains. The presence of an electron attractor group on the aromatic ring as chloro group (5b) is favorable for that antibacterial activity. Derivatives (5c, 5d, 5f) containing the aromatic ring substituted by an electron donor groups (-OCH₃, OH) inhibit the activity. All the newly synthesized compounds exhibit promising antimicrobial properties.