3-Ethyl-4-(2-benzenesulfonyloxy)-benzylideneamino-4,5-dihydro-1H-1,2,4-triazol-5-one has been optimized using the DFT/B3LYP and B3PW91 methods with the 6-311G(d,p) basis set in the ground state. The vibrational (IR) frequencies, 1H and 13C NMR chemical shift values (in gas phase and in DMSO solvent), nonlinear optical properties (NLO), HOMO−LUMO analysis and molecular electrostatic potential surfaces of 3-Ethyl-4-(2-benzenesulfonyloxy)-benzylideneamino-4,5-dihydro-1H-1,2,4-triazol-5-one have been calculated using the DFT/B3LYP and DFT/B3PW91 methods with the 6-311G(d,p) basis set. IR absorption frequencies of titled molecule were calculated by same methods. Theoretically calculated IR data are multiplied with appropriate adjustment factors. The data obtained according to DFT/B3LYP and DFT/B3PW91 are formed using theoretical infrared spectrums. The veda4f program was used in defining IR data which were calculated data. 1H-NMR and 13C-NMR isotropic shift values were calculated by the method of GIAO using the program package Gaussian G09W. Experimental and theoretical values were inserted into the grafic according to equatation of δ exp=a+b. δ calc. The spectroscopic and structural data of titled molecule has been calculated by using 6-311G(d,p) basis set with DFT/B3LYP and DFT/B3PW9. The values obtained were compared with experimental values.

It is known that acetyl derivatives, Schiff bases, and Mannich bases obtained from 1,2,4-triazol-5-ones have significant antibacterial and antioxidant activities. Herein, 27 new 1,2,4-triazole derivatives were synthesized, and their antioxidant and antibacterial properties were investigated. The metal chelating activity of the synthesized compounds and especially the effect against gram-positive bacteria were found to be significant. The effect against gram-negative strains was also important. Structure determination of the synthesized com­pounds was performed on the basis of their ¹H and ¹³C NMR, IR, and high-resolution mass spectra.

In the present study, 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (3c, f, e) reacted with 4-methylthiobenzaldehyde to afford 3-alkyl(aryl)-4-(4-methylthio-benzylideneamino)-4,5-dihidro-1H-1,2,4-triazol-5-ones (4c, f, e). The structures of three new compounds were established from the elemental analysis, IR, 1H NMR, and 13C NMR spectral data. The newly synthesized and recently synthesized 3-alkyl(aryl)-4-(4-methylthiobenzylideneamino)-4,5-dihidro-1H-1,2,4-triazol-5-one derivatives were analyzed using three methods for antioxidant activities. Compound 4a showed the best activity for the metal chelating effect. Furthermore, the compounds' antimicrobial activity was screened.

In this study, a total of nine new 2-[(3-alkyl/aryl-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl)azomethine]phenyl 2,5-dichlorobenzenesulfonates (4a-i) were synthesized through the reactions of 2-formylphenyl 2,5-dichlorobenzenesulfonate (3) with 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2a-i). The compounds 4a, 4e, 4g and 4h were successfully synthesized with yields exceeding 90%. Compounds 4a-i were elucidated using 1H, 13C NMR and IR spectroscopic methods. The spectroscopic data were compared with the literature, and the results were found to be consistent. The antioxidant effects of compounds 4a–i were investigated using three different methods, and it was found that compounds 4a-i showed metal chelation activity close to that of α-tocopherol, which was used as the standard. Additionally, the antimicrobial properties of the compounds 4a–i were evaluated using the agar well diffusion method against six different bacterial strains. The antimicrobial properties of the new compounds (4a-i) were compared with those of standard antibiotics such as neomycin, streptomycin, and ampicillin. It was observed that compound 4a exhibited better antimicrobial activity than neomycin and streptomycin, and comparable activity to ampicillin.

1,2,4-Triazole derivatives are widely investigated as bioactive heterocyclic compounds with diverse biological properties; however, their potential effects on avian embryonic development remain insufficiently characterized. This study aimed to synthesize selected Mannich-type 1,2,4-triazol-5-one derivatives and evaluate their in vitro biological activities, predicted enzyme interactions, and in ovo hatchability outcomes in broiler embryos. Three derivatives (3a–3c) were synthesized and structurally characterized using Fourier-transform infrared (FT-IR), proton nuclear magnetic resonance (¹H-NMR), and carbon-13 nuclear magnetic resonance (¹³C-NMR) spectroscopy. Their reducing capacity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, metal-chelating capacity, and antimicrobial activity were evaluated. Molecular docking analyses were performed against carbonic anhydrase II and catalase, using acetazolamide and 3-amino-1,2,4-triazole as reference inhibitors, respectively. For the in ovo assessment, fertilized Ross 308 eggs were allocated to non-injected control, vehicle control, and compound-treated groups. Compounds 3a, 3b, and 3c were administered on incubation day 17 at 20, 10, and 5 mg/egg, respectively, as literature-supported, compound-specific exploratory exposure levels. The compounds exhibited weak reducing capacity, negligible DPPH radical-scavenging activity, pronounced metal-chelating capacity, and selective antimicrobial activity against several bacterial strains, whereas no inhibition was observed against Escherichia coli. Docking analysis predicted favorable interactions with both enzyme targets, with compound 3c showing the most favorable binding energies. Baseline egg weights were comparable among groups, indicating that initial egg weight was unlikely to influence hatchability outcomes. Complete hatch failure occurred in all compound-treated groups, whereas hatchability was observed in the control groups. These findings suggest that the tested derivatives may adversely affect embryonic development under the applied in ovo conditions. Their pronounced metal-chelating capacity, together with the predicted interactions with carbonic anhydrase II and catalase, provides a plausible mechanistic framework for interpreting the observed embryonic outcomes. The molecular docking results complement the experimental findings and provide supportive in silico evidence for these potential interactions. These findings contribute to the limited literature on the in ovo evaluation of synthetic Mannich-type 1,2,4-triazol-5-one derivatives and provide preliminary evidence regarding their embryotoxic potential. Further dose-dependent, mechanistic, histopathological, and enzyme-based studies are required to clarify the biological basis of the observed effects and to guide future evaluation of these compounds in in ovo, biomedical, and veterinary applications.

Bu çalışmada, 3-hidroksibenzaldehit ile 2,5-diklorobenzensulfonil klorürün trietilamin ortamındaki reaksiyonundan yeni 3-formilfenil 2,5-diklorobenzensulfonat (2) bileşiği sentezlenmiştir. Sentezlenen benzaldehit türevi bileşik (2) ile literatürde kayıtlı dokuz adet 3-alkil/aril-4-amino-4,5-dihidro-1H-1,2,4-triazol-5-on (1a-1i) bileşikleri reaksiyona sokulmuştur. Reaksiyon sonucunda dokuz adet yeni 3-[(3-alkil/aril-4,5-dihidro-1H-1,2,4-triazol-5-on-4-il)-azometin]-fenil 2,5-diklorobenzensulfonat (3a-3i) bileşikleri sentezlenmiştir. Sentezlenen yeni Schiff bazı bileşiklerin (3a-3i) yapıları IR, 1H-NMR, 13C-NMR spektroskopik yöntemler ile karakterizasyonu yapılmıştır. Yeni bileşiklerin (3a-3i) hem antibakteriyel hem de antioksidan özelliklerine bakılarak biyolojik özellikleri incelenmiştir. Antibakteriyel özellikleri Agar kuyucuk difüzyon metodu ile incelenmiş ve gözlemlemeler sonucunda 3a-3d, 3h ve 3i bileşiklerinin iyi antibakteriyel aktiviteye sahip olduğu belirlenmiştir. Antioksidan özellikleri Blois, Dinis, Oyaizu metotları ile incelenmiş ve sentezlenen yeni bileşiklerin (3a-3i) standart olarak kullanılan α-tokoferole oldukça yakın düzeyde metal şelat aktivitesine sahip olduğu gözlemlenmiştir. Ayrıca, yeni Schiff bazı bileşiklerinin (3a-3i) dört farklı susuz çözücüde (DMF, izopropil alkol, aseton ve tert-butil alkol) tetrabutilamonyum hidroksit (TBAH) ile titre edilerek asidik özelliklerine bakılmış, yarı nötralizasyon potansiyelleri ve bunlara karşılık gelen pKa değerleri belirlenmiştir.