3.1. Synthesis of 1,2,4-Triazole-3-Thione Derivatives

Four 1,2,4-triazole-3-thione derivatives, depicted in Figure 1, were synthesized as described in the published articles [10,11,13,15]. In brief, the respective carboxylic acid hydrazides were reacted with aryl/aryl isothiocyanates in order to obtain 1,4-disubstituted thiosemicarbazide derivatives. Their alkaline dehydrocyclization in 2% NaOH produced the respective 4,5-disubstituted-1,2,4-triazole-3-thione derivatives. The obtained compounds were crystallized from EtOH, and their structures were confirmed on the basis of 1H- and 13C-NMR spectra (Bruker Avance, 300 MHz). Reagents and solvents were purchased from Sigma-Aldrich (St. Louis, MO, USA) and POCh Gliwice (Gliwice, Poland), respectively.