Search Results (16)

As examples of “Click Chemistry”, the reaction of 1-(oxiran-2-ylmethyl)piperidine with several 1,2,4-triazoles derivatives was studied. As a result, the reaction shows that the oxirane ring opens regiospecifically, according to Krasusky’s rule, without using a catalyst. The basic nitrogen present in 1-(oxiran-2-ylmethyl)piperidine has a catalytic (anchimer) effect. Full article

Thiosemicarbazones (TSCs) with their modular character (thiosemicarbazides + carbonyl compound) allow broad variation of up to four substituents on the main R¹R²C=N(1)–NH–C(S)–N(4)R³R⁴ core and are thus interesting tools for the formation of conjugates or the functionalization of nanoparticles (NPs). In this work, di-2-pyridyl ketone was introduced for the coordination of metals and 9-anthraldehyde for luminescence as R¹ and R² to TSCs. R³ and R⁴ substituents were varied for the formation of conjugates. Amino acids were introduced at the N4 position to produce [R¹R²TSC–spacer–amino acid] conjugates. Further, functions such as phosphonic acid (R–P(O)(OH)₂), D-glucose, o-hydroquinone, OH, and thiol (SH) were introduced at the N4 position producing [R¹R²TSC–spacer–anchor group] conjugates for direct NP anchoring. Phenyl, cyclohexyl, benzyl, ethyl and methyl were used as spacer units. Both phenyl phosphonic acid TSC derivatives were bound on TiO₂ NPs as a first example of direct NP anchoring. [R¹R²TSC–spacer–end group] conjugates including OH, S–Bn (Bn = benzyl), NH–Boc (Boc = tert-butyloxycarbonyl), COOtBu, C≡CH, or N₃ end groups were synthesized for potential covalent binding to functional molecules or functionalized NPs through amide, ester, or triazole functions. The synthesis of the thiosemicarbazides H₂NNH–C(S)–NR₃R₄ starting from amines, including amino acids, SCCl₂ or CS₂, and hydrazine and their condensation with dipyridyl ketone and anthraldehyde led to 34 new TSC derivatives. They were synthesized in up to six steps with overall yields ranging from 10 to 85% and were characterized by a combination of nuclear magnetic resonance spectroscopy and mass spectrometry. UV-vis absorption and photoluminescence spectroscopy allowed us to easily trace the dipyridyl imine and anthracene chromophores. Full article

Efficient recovery of gallium (Ga) from vanadium slag processing residue (VSPR) solution is of great significance for environmental protection and resource utilization, but improving its selective adsorption against the coexisting Sc³⁺ and In³⁺ is still challenging. Herein, a novel adsorbent consisting of 4-amino-3-hydrazino-1,2,4-triazol-5-thiol (AHTZT)-modified graphene oxide (GO-AHTZT) was successfully synthesized that exhibits a higher adsorption selectivity for Ga³⁺ in VSPR solution with coexisting Sc³⁺ and In³⁺. Under optimal conditions, the adsorption capacity of GO-AHTZT for Ga³⁺ can reach 23.92 mg g⁻¹, which is 4.9 and 12.6 times higher than that for Sc³⁺ (4.87 mg g⁻¹) and In³⁺ (1.90 mg g⁻¹) adsorption, indicating the excellent anti-interference ability of GO-AHTZT against Sc³⁺ and In³⁺. The process and mechanism of Ga³⁺ adsorption onto GO-AHTZT was also studied and discussed in detail. By measuring the adsorption process and by characterizing the adsorbent before and after adsorption, we demonstrate that the selective interaction between the Ga³⁺- and N-containing groups in AHTZT is the main reason for the improved adsorption selectivity. This work opens up an avenue for the design and synthesis of highly selective adsorbents for Ga³⁺ in complex VSPR solutions. Full article

The reaction of 2-bromo-1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethan-1-one (1) with 4-amino-5-((2,4-dichlorophenoxy)methyl)-4H-1,2,4-triazole-3-thiol (2) in absolute ethanol in the presence of triethyl amine as catalyst gave 2-((4-amino-5-((2,4-dichlorophenoxy)methyl)-4H-1,2,4-triazol-3-yl)thio)-1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethan-1-one (3) in 73% yield. The structure of the title heterocycle (3) was confirmed by X-ray single crystal diffraction and spectral analyses (NMR and IR). Full article

In this study, we investigated the abilities of nitrogen and sulfur heterocyclic carbenes of benzotriazole, 2-mercaptobenzothiazole, 8-hydroxyquinoline, and 3-amino-1,2,4-triazole-5-thiol regarding adsorption on an Al-Mg-Si alloy toward corrosion inhibition of the surface. Al-Si(14), Al-Si(19), and Al-Si(21) in the Al-Mg-Si alloy surface with the highest fluctuation in the shielding tensors of the “NMR” spectrum generated by intra-atomic interaction directed us to the most influence in the neighbor atoms generated by interatomic reactions of N → Al, O → Al, and S → Al through the coating and adsorbing process of Langmuir adsorption. The values of various thermodynamic properties and dipole moments of benzotriazole, 2-mercaptobenzothiazole, 8-hydroxyquinoline, and 3-amino-1,2,4-triazole-5-thiol adsorbed on the Al-Mg-Si increased by enhancing the molecular weight of these compounds as well as the charge distribution between organic compounds (electron donor) and the alloy surface (electron acceptor). Finally, this research can build up our knowledge of the electronic structure, relative stability, and surface bonding of various metal alloy surfaces, metal-doped alloy nanosheets, and other dependent mechanisms such as heterogeneous catalysis, friction lubrication, and biological systems. Full article

In a basic medium, 5-Mercapto-1,2,4-triazoles pass into the thiol form, allowing their transformation into sodium salts, which, in reaction with sodium monochloroacetate, lead to sodium 5-thioacetates of 1,2,4-triazoles-3,4-disubstituted. Sulfur derivatives converted to pivalic mixed anhydrides were used as active forms in the acylation of 6-amino penicillanic acid (6-AP) to obtain new semisynthetic penicillins. They contain in the molecule, together with the β-lactam ring, the nucleus 3-[(5-nitroindazol-1′-yl-methyl)]-4-aryl-5-mercapto-1,2,4-triazole, both contributing to an important antibacterial effect. The structure of the new antibiotics was confirmed by the results of elemental and spectral analysis (FT-IR, ¹H- and ¹³C-NMR). The synthetic penicillins were tested for toxicological action and antibacterial activity and the obtained results were close to those for amoxicillin, the reference drug. Full article

The electrochemical synthesis of conductive polymers (CPs) or semiconductors (SCs) is influenced by several parameters, such as the choice of monomers, solvents, support electrolytes, and the nature of dopants, which induce electrical conductivity in conjugated organic polymers. This work describes the electropolymerization of 3-amino-1,2,4-triazole-5-thiol (ATT) on a 60Cu-40Zn brass alloy. The synthesis of polymer film by electrochemical method was carried out by cyclic voltammetry and chronoamperometry in a medium of KOH 0.1 M dissolved in pure methanol CH₃OH. The voltammograms obtained show that the ATT oxidizes anodically at a potential of 1.15 V. The effect of the sweep speed shows that the increase in the sweep speed is accompanied by the increase in the intensity of the first oxidation peak, indicating the acceleration of the process studied, and also indicating that the oxidation reaction of the monomers is essentially irreversible and controlled by a diffusion process. The polymer film analysis by electrochemical impedance spectroscopy shows a capacitive then diffusional behavior—this is a typical effect of conductive polymers. Analysis by EDX justifies the formation of a polymer film on the metal surface. This work was completed by theoretical calculation, which showed that the oxidation of the ATT considerably reduces the energy value of Gap $E_{gap}$, reaching a value of 2.07 eV—this shows that the polymer film is a semiconductive material. Full article

This study of the interaction system of binucleophilic 3-substituted 4-amino-4H-1,2,4-triazole-5-thiols and 3-phenyl-2-propynal made it possible to develop a new approach to synthesis of such isomeric classes as 7-benzylidene-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine and 8-phenyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazepine. Among the 20 compounds studied in vitro against influenza A/Puerto Rico/8/34 (H1N1) virus, half of them demonstrated selectivity index (SI) of 10 or higher and one of them (4-((3-phenylprop-2-yn-1-yl)amino)-4H-1,2,4-triazole-3-thiol) possessed the highest (SI > 300). Docking results and values showed that the preferred interactant for our ligands was M2 proton channel of the influenza A virus. Protein-ligand interactions modeling showed that the aliphatic moiety of ligands could negatively regulate target activity level. Full article

Novel anthracene-based Schiff base derivative (4-(anthracen-9-ylmethylene) amino)-5-phenyl-4H-1,2,4-triazole-3-thiol; AT2) is synthesized and utilized as an aggregation-induced emission-enhancement (AIEE) active probe to detect Zn²⁺ and Tyrosine. Ultraviolet-visible absorption/photoluminescence (UV-vis/PL) spectroscopy studies on the AIEE property of AT2 (in ethanol) with increasing water fractions (f_w: 0–97.5%) confirm the J-type aggregation. Excellent sensor selectivity of AT2 to Zn²⁺ and its reversibility with Tyrosine are demonstrated with PL interrogations. 2:1 and 1:1 stoichiometry and binding sites of AT2-Zn²⁺ and Tyrosine-Zn²⁺ complexes are elucidated from Job plots, HR-mass, and ¹H-NMR results. Nanomolar-level detection limits (LODs) of Zn²⁺ (179 nM) and Tyrosine (667 nM) and association constants (K_as) of 2.28 × 10⁻⁶ M⁻² (for AT2-Zn²⁺) and 1.39 × 10⁻⁷ M⁻¹ (for Tyrosine-Zn²⁺) are determined from standard deviation and linear fittings. Nanofiber formation in AIEE and aggregated/dispersed nanoparticles in the presence of the Zn²⁺/Tyrosine are supported by scanning-electron microscope (SEM), transmission-electron microscope (TEM), atomic-force microscope (AFM), and dynamic-light scattering (DLS) investigations. Density-functional theory (DFT) studies confirm an “On-Off” twisted intramolecular charge transfer/photo-induced electron transfer (TICT/PET) and “On-Off-On” PET mechanisms for AIEE and sensors, respectively. B16-F10 cellular and zebrafish imaging are conducted to support the applications of AIEE and sensors. Full article

The synthesis of mixed-ligand complexes is considered an important strategy for developing new metal complexes of enhanced biological activity. This paper presents the synthesis, characterization, in vitro antimicrobial assessment, and theoretical molecular docking evaluation for synthesized oxidovanadium (V) complexes. The proposed structures of the synthesized compounds were proved using elemental and different spectroscopic analysis. The antimicrobial tests showed moderate activity of the compounds against the Gram-positive bacterial strains and the fungal yeast, whereas no activity was observed against the Gram-negative bacterial strains. The performance of density functional theory (DFT) was conducted to study the interaction mode of the targeted compounds with the biological system. Calculating the quantitative structure-activity relationship (QSPR) was performed depending on optimization geometries, frontier molecular orbitals (FMOs), and chemical reactivities for synthesized compounds. The molecular electrostatic potentials (MEPs) that were plotted link the interaction manner of synthesized compounds with the receptor. The molecular docking evaluation revealed that the examined compounds may possess potential antibacterial activity. Full article

Background: Dehydropeptides are analogs of peptides containing at least one conjugate double bond between α,β-carbon atoms. Its presence provides unique structural properties and reaction centre for chemical modification. In this study, the series of new class of dipeptides containing S-substituted dehydrocysteine with variety of heterocyclic moieties was prepared. The compounds were designed as the building blocks for the construction of artificial metalloenzymes (artzymes). Therefore, the complexing properties of representative compounds were also evaluated. Furthermore, the acknowledged biological activity of natural dehydropeptides was the reason to extend the study for antiproliferative action of against several cancer cell lines. Methods: The synthetic strategy involves glycyl and phenylalanyl-(Z)-β-bromodehydroalanine as a substrate in one pot addition/elimination reaction of thiols. After deprotection of N-terminal amino group the compounds with triazole ring were tested as complexones for copper(II) ions using potentiometric titration and spectroscopic techniques (UV-Vis, CD, EPR). Finally, the antiproliferative activity was evaluated by sulforhodamine B assay. Results and Conclusions: A simple and efficient procedure for preparation of dipeptides containing S-substituded dehydrocysteine was provided. The peptides containing triazole appeared to be strong complexones of copper(II) ions. Some of the peptides exhibited promising antiproliferative activities against number of cancer cell lines, including cell lines resistant to widely used anticancer agent. Full article

In the present investigation, the parent compound 4-amino-5-(4-fluoro-3-phenoxyphenyl)-4H-1,2,4-triazole-3-thiol (1) and its Schiff bases 2, 3, and 4 were subjected to whole-cell anti-TB against H37Rv and multi-drug-resistant (MDR) strains of Mycobacterium tuberculosis (MTB) by resazurin microtiter assay (REMA) plate method. Test compound 1 exhibited promising anti-TB activity against H37Rv and MDR strains of MTB at 5.5 µg/mL and 11 µg/mL, respectively. An attempt to identify the suitable molecular target for compound 1 was performed using a set of triazole thiol cellular targets, including β-ketoacyl carrier protein synthase III (FABH), β-ketoacyl ACP synthase I (KasA), CYP121, dihydrofolate reductase, enoyl-acyl carrier protein reductase, and N-acetylglucosamine-1-phosphate uridyltransferase. MTB β-ketoacyl ACP synthase I (KasA) was identified as the cellular target for the promising anti-TB parent compound 1 via docking and molecular dynamics simulation. MM(GB/PB)SA binding free energy calculation revealed stronger binding of compound 1 compared with KasA standard inhibitor thiolactomycin (TLM). The inhibitory mechanism of test compound 1 involves the formation of hydrogen bonding with the catalytic histidine residues, and it also impedes access of fatty-acid substrates to the active site through interference with α5–α6 helix movement. Test compound 1-specific structural changes at the ALA274–ALA281 loop might be the contributing factor underlying the stronger anti-TB effect of compound 1 when compared with TLM, as it tends to adopt a closed conformation for the access of malonyl substrate to its binding site. Full article

The emergence of bacteria that co-express serine- and metallo- carbapenemases is a threat to the efficacy of the available β-lactam antibiotic armamentarium. The 4-amino-1,2,4-triazole-3-thione scaffold has been selected as the starting chemical moiety in the design of a small library of β-Lactamase inhibitors (BLIs) with extended activity profiles. The synthesised compounds have been validated in vitro against class A serine β−Lactamase (SBLs) KPC-2 and class B1 metallo β−Lactamases (MBLs) VIM-1 and IMP-1. Of the synthesised derivatives, four compounds showed cross-class micromolar inhibition potency and therefore underwent in silico analyses to elucidate their binding mode within the catalytic pockets of serine- and metallo-BLs. Moreover, several members of the synthesised library have been evaluated, in combination with meropenem (MEM), against clinical strains that overexpress BLs for their ability to synergise carbapenems. Full article

Novel Cd²⁺ ions mediated reproducible hybrid graphite-diamond nanowire (G-DNWs; Cd²⁺-NDS1 NW) growth from 4-Amino-5-phenyl-4H-1,2,4-triazole-3-thiol (S1) functionalized diamond nanoparticles (NDS1) via supramolecular assembly is reported and demonstrated through TEM and AFM images. FTIR, EDX and XPS studies reveal the supramolecular coordination between functional units of NDS1 and Cd²⁺ ions towards NWs growth. Investigations of XPS, XRD and Raman data show the covering of graphite sheath over DNWs. Moreover, HR-TEM studies on Cd²⁺-NDS1 NW confirm the coexistence of less perfect sp² graphite layer and sp³ diamond carbon along with impurity channels and flatten surface morphology. Possible mechanisms behind the G-DNWs growth are proposed and clarified. Subsequently, conductivity of the as-grown G-DNWs is determined through the fabrication of a single Cd²⁺-NDS1 NW device, in which the G-DNW portion L2 demonstrates a better conductivity of 2.31 × 10⁻⁴ mS/cm. In addition, we investigate the temperature-dependent carrier transport mechanisms and the corresponding activation energy in details. Finally, comparisons in electrical resistivities with other carbon-based materials are made to validate the importance of our conductivity measurements. Full article

A series of 5-substituted-4-amino-1,2,4-triazole-3-thioesters was synthesized by converting variously substituted organic acids successively into the corresponding esters, hydrazides, 5-substituted-1,3,4-oxadiazole-2-thiols, 5-substituted-1,2,4-triazole-2-thiols and 5-substituted-1,3,4-oxadiazole-2-thioesters. Finally the target compounds were obtained by refluxing 5-substituted-1,3,4-oxadiazole-2-thioesters in the presence of hydrazine hydrate and absolute alcohol. The structures of the synthesized compounds were established by physicochemical and spectroscopic methods. The synthesized compounds were evaluated for their in vitro antifungal activity. Some of the evaluated compounds possessed significant antifungal activity as compared to a terbinafine standard. Full article