Synthesis of novel 1,2,3-thiadizoles and 1,2,3-selenadiazoles as new antimicrobial agents

Abstract

A series of novel 1,2,3-thiadiazoles and 1,2,3-selenadiazoles having a long alkyl chain were synthesized by reacting semicarbazones with SOCl₂ and SeO₂, respectively. The structures of the target compounds 5–12 were confirmed by spectroscopy (IR, ¹H NMR, ¹³C NMR, and MS) and elemental analysis. Their antibacterial and antifungal activities were evaluated against six bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis, Staphylococcus epidermidis, Staphylococcus aureus) and three fungi (Candida albicans, Candida parapsilosis, Candida tropicalis). The results of bioassays indicated that the compounds 5-Dodecyl-4-(4-methoxy-phenyl)-1-3]selenadiazole (7), 4-Methyl-5-tetradecyl-1-3]selenadiazole (8) and 5-Dodecyl-4-(4-methoxy-phenyl)-1-3]thiadiazole (11) displayed moderate antibacterial activity against S. Epidermidis. On the other hand, according to antifungal screening results, compounds 5-Dodecyl-4-phenyl-1-3]selenadiazole (5), 4-p-Tolyl-5-undecyl-1-3]selenadiazole (6), and 5-Dodecyl-4-(4-methoxy-phenyl)-1-3]selenadiazole (7) exhibited significant antifungal activities studied yeast strains.