Synthesis, Characterization and Antimycobacterial Activity of Some Substituted Phenylpyridazinone Derivatives

Aseries 6-phenyl-2-(substituted methyl)-dihydropyridazinone derivatives (3a–3f) were synthesized using the interaction of 6-phenylpyridazinone with cyclic secondary amine by Mannich reaction and evaluated for antimycobacterial activity against Mycobacterium tuberculosis H37Rv strain by Microplate Alamar Blue Assay (MABA) method. All the synthesized compounds (3a–3f) were characterized by IR, ¹H NMR, and mass spectroscopy methods. The results indicated that 6-phenyl-2-(Imidazol-1-ylmethyl)-4,5-dihydro-2H-pyridazin-3-one (3b) and 6-phenyl-2-(1,2-dihydro-phenothiazin-10-ylmethyl)-4,5-dihydro-2H-pyridazin-3-one (3f) exhibited highest antimycobacterial activity. Other compounds (3a, 3c-3e) showed less significant antimycobacterial activity. The most effective compounds (3b and 3f) possessed MIC of 6.25μg/mL that was equal to that of reference drugs Streptomycin and Ciprofloxacin.