Synthesis of Some Schiff's Bases Containing 1,3,4-Thiadiazole Ring and Their Properties as Antioxidants

A series of Schiff's bases containing 1,3,4-thiadiazole (2,5-di(N-substitutedbenzylideneamino)1,3,4-thiadiazole) were prepared through the reaction of thiosemicarbazide with chloro cyanide. The product was directly reacted with benzaldehyde and substituted benzaldehydes. The synthetic compounds (0-10) were identified using the analytical and spectral means. The antioxidant properties were measured of the prepared compounds using the metal ions (Fe +3 , Cu +2 ), and Ferrozine and 2,9-dimethyl-1,10-phenanthroline (neocuproine). The results showed that the compound no. 5 [2,5-di(N-(4-hydroxybenzylideneamino)-1,3,4-thiadiazole] reveals the highest antioxidant activity through this work. Introduction The progress achieved in the synthesis of heterocyclic compounds with a biological potential is due to improvement of the methodological study of tested substances too. It is known that many 1,3,4thiadiazole and 1,2,4-triazole derivatives have biological activity, with their antibacterial [1-3], antimycobacterial [4,5], antimycotic [6], antifungal [7,8], antidepressive [9], and cardiotonic [10] action being notable. Recent research has also established for these heterocycles an analgesic [11] and antiinflammatory [12,13] activity. Meanwhile, Nacylated amino acids are known for their hepatoprotective [14], antimicrobial [15,16] and antitumoral [17,18] action. In the view of the facts mentioned above and as part of our initial efforts to discover potentially active new agents. Hence, it has been reported that 1,3,4-thiadiazole derivatives were widely used for their antioxidant activity [19]. Experimentals and Methods The synthesis of the target molecule is shown in the sequences of reactions depicted in the following scheme. The FTIR spectral data were recorded on FTIR-8300 Fourier Transform Infrared Spectrophotometer SHIMADZU using potassium bromide disc. Double-beam UV-Visible spectrophotometer (UV 1650 CP), SHIMADZU. Melting points ( o C) were recorded on hot stage Gallen Kamp melting point apparatus and were uncorrected. Chemical names follow IUPAC nomenclature.