Synthesis and antimicrobial activity of novel 2-substituted benzimidazole, benzoxazole and benzothiazole derivatives

Novel benzimidazole, benzoxazole and benzothiazole derivatives were designed and synthesized from p-N,N-diethyl amino salicylaldehyde with different substituted o-phenylenediamine or o-aminophenol or o-aminothiophenol. Antimicrobial activities were tested against bacterial strain (Escherichia coli, Staphylococcus aureus) and fungal strain (Candida albicans and Aspergillus niger), results reveals that compounds have potent antimicrobial activity. In an endeavor to find a new class of antimicrobial agents, a series of 2-(1H-benzimidazol-2-yl)-5-(diethylamino)phenol, 2-(1,3-benzoxazol-2-yl)-5-(diethylamino)phenol, 2-(1,3-benzothiazol-2-yl)-5-(diethylamino)phenol and their derivatives were synthesized starting from p-N,N-diethyl amino salicylaldehyde with different substituted o-phenylenediamine or o-aminophenol or o-aminothiophenol. The newly synthesized compounds were characterized by FT-IR, 1H NMR and LC–MS analysis. All compounds were evaluated for in vitro antibacterial activities against Escherichia coli and Staphylococcus aureus strains and in vitro antifungal activity against Candida albicans and Aspergillus niger strains by using serial dilution method. The antibacterial activities were expressed as the minimum inhibitory concentration (MIC) in μg/mL.