Synthesis, Characterization, and Antioxidant, Antimicrobial and Toxic Properties of Novel Δ2 -1,3,4-thiadiazoline and Δ2 -1,3,4-selenadiazoline Derivatives

Abstract

Two new series of N-(4-acetyl-5-aryl-4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamide and N-(4-acetyl-5-aryl-4,5-dihydro1,3,4-selenadiazol-2-yl)acetamide compounds (where aryl = 4-nitrophenyl, 4-hydroxy-3-methoxyphenyl, 3-ethoxy-4- hydroxyphenyl, 2-chloroquinolinyl, and 6-chloro-4-oxo-4H-chromenyl) were synthesized in good yields by heterocyclization of thiosemicarbazones (TSCs) and selenosemicarbazones (SSCs) with acetic anhydride, respectively. The new TSCs and SSCs compounds was prepared by condensation reaction of thiosemicarbazide and Selenosemicarbazide with aromatic aldehydes in acidic medium. The structures of newly synthesized 1,3,4-thiadiazoline (TDZs) and 1,3,4-selenadiazoline (SDZs) derivatives were characterized by the analytical and spectroscopic method such as IR, 1 H NMR, 13C NMR, mass spectra and elemental analysis. The purity of compound and evaluation of Rf value were determined by TLC. The toxicity of new compounds was assayed via the determination of their LD50 value by using Dixon’ s up and down method. The antibacterial activity of 1,3,4-thiadiazoline and 1,3,4-selenadiazoline compounds were tested in vitro against Staphylococcus aureus, Bacillus, Escherichia coli and Pseudomonas aeruginosa. Finally, antioxidant efficiency of all compounds were detected according to β-carotene bleaching method.

First Exclusive Stereo‐ and Regioselective Preparation of 5‐Arylimino‐1,3,4‐Selenadiazole Derivatives: Synthesis, NMR analysis, and Computational Studies

“…To highlight the versatile pharmacology of selenadiazoles, several bioactive species performing various biological and chemical roles are summarized in Figure 1 (1–6). These include insecticidal, [2] antifungal, [37] antiglutaminase, [38–40] antibacterial, [41] anticancer, [42] and antioxidant functions [43] …”

“…These include insecticidal, [2] antifungal, [37] antiglutaminase, [38][39][40] antibacterial, [41] anticancer, [42] and antioxidant functions. [43] Compared to the chemistry and biological properties of 1,2,3-selenadiazole, [2][3][4][5][6] 1,2,4-selenadiazole, [7,8] 1,2,5-selenadiazole and 1,3,4-thiadiazole, [44] those of 1,3,4-selenadiazole remain much less known. Although the selenadiazole nucleus possesses multiple possible reactive sites, the ring is electron deficient owing to the electron-withdrawing characteristic of the two nitrogen atoms and is unsusceptible to electrophilic substitution but reactive toward nucleophilic attack.…”