Synthesis of Novel Triazolyl Thiourea Derivatives and Their Antibacterial Activity

4-Amino-5-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione was synthesized in three steps from carbon disulfide, hydrazine hydrate, and acetic acid. Its reaction with benzoyl isothiocyanates prepared from substituted benzoyl chlorides and ammonium thiocyanate afforded the corresponding N-benzoyl-N′-triazolyl-thioureas. The obtained compounds were screened for antibacterial activity against Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922), and Pseudomonas aeruginosa (ATCC 27853). Their antibacterial activity against gram-positive bacteria was higher than against gram-negative bacteria, and derivatives containing electron-withdrawing groups were more active than those with electron-donating substituents.