Synthesis, Characterization and Antibacterial Activity of some Novel Thiosemicarbazides, 1,2,4-Triazol-3-thiols and their S-substituted Derivatives

The thiosemicarbazides 3a-c were appeared by reaction of the corresponding substituted hydrazides 1a-c with allylisothiocyanate 2. Synthesis of some novel 1,2,4-triazole-thiols 4a-c bearing a pyridyl unit using 1-(x-picolinoyl)-4-allyl-thiosemicarbazides (x = 2,3,4) in an alkaline solution, is reported. Also, the S-alkylation of triazole derivatives 5-7a-c is described. The structure of the synthesized compounds resulted from the IR, 1H and -13C NMR spectroscopy and elemental analysis data. The antibacterial studies to all of the synthesized compounds against B. cereus, E. coli, P. aeroginosa, S. aureus and E. faecalis were evaluated. Also, the compounds that indicate noticeable activities, their MIC (Minimum inhibitory concentration) values are reported. Some of these compounds such as 7a, 4a and 3a exhibited a good to significant antibacterial activity.