This study presents the synthesis and spectral analysis of new derivatives of 1,2,4-triazole-3-thione and 1,3,4-thiadiazole. New compounds were prepared by cyclization reaction of acyl thiosemicarbazide derivatives in the presence of alkaline and acidic media. All synthesized compounds were screened for their in vitro antibacterial activity by using the agar dilution technique. Six of the compounds had potential activity against Gram-positive bacteria (minimal inhibitory concentration [MIC] = 15.63–500 μg/mL). Some compounds showed good activity especially against Bacillus subtilis ATCC 6633 (MIC = 15.63–250 μg/mL), Staphylococcus aureus ATCC 25923 (MIC = 31.25–250 μg/mL), and Micrococcus luteus ATCC 10240 (MIC = 125–250 μg/mL).Graphical abstract

By the reaction of 4-methyl-4H-1,2,4-triazole-3-thiol with ethyl bromoacetate, ethyl [(4-methyl-4H-1,2,4-triazol-3-yl)sulfanyl]acetate (1) was obtained. This compound was converted to [(4-methyl-4H-1,2,4-triazol-3-yl)sulfanyl]acetohydrazide (2). In the reaction of 2 with isothiocyanates, new thiosemicarbazides 3a-3g were obtained. The cyclization of 3a-3g in 2% aqueous solution of sodium hydroxide led to the formation of 4H-1,2,4-triazole-3(2H)-thione derivatives 4a-4g, whereas the cyclization in acid media led to the formation of 2-amino-1,3,4-thiadiazole derivatives 5a-5g. Molecular structure was confirmed by X-ray structure analysis of 3a, 4g, 5a and 5g. Compounds 4a, 4b and 4g were investigated pharmacologically to determine their effect on the central nervous system (CNS) in mice.

ABSTRACT:The synthesis of 4-[3-(2-methylfuran-3-yl)-5-thioxo-1,2,4-triazolin-4-yl]

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On a four series of 1-azolil-4-aryl/alkyl-