Acta Chimica Slovenica最新文献

4-bromobenzenesulfonate derivatives (I and II) were prepared and characterized by FTIR and NMR spectroscopic methods and density functional theory. Acceptable deviations were found where the scaled vibrational frequencies at B3LYP/6-311++G(d,p) were found to coincide with the experimentally observed values. Optimized molecular structures, UV-Vis and NLO properties were obtained for the compounds. The stability of the molecules arising from hyper conjugative interactions and charge delocalization has been analyzed using Natural Bond Orbital (NBO) analysis. The calculated HOMO and LUMO energies indicated that charge transfer occurred within the molecules.  This study investigated the interactions between two synthesized compounds, I and II, and four receptor proteins: EGFR, VEGFR1, acetylcholinesterase, and Leishmania infantum trypanothione reductase. Molecular docking analysis was performed to evaluate binding energies and inhibition constants, revealing key interactions that provide insights into the therapeutic potential of the compounds.

Schiff bases bearing halo substituent groups have interesting biological activities. In this work, two new hydrazone type Schiff bases N'-(3,5-dibromo-2-hydroxybenzylidene)-3-methylbenzohydrazide (HL1) and N'-(4-chloro-2-hydroxybenzylidene)-4-fluorobenzohydrazide (HL2), bearing bromo, chloro and fluoro substituent groups were synthesized. The compounds reacts with various copper salts to form three copper(II) complexes with interesting structures. The complexes are [CuBrL1]∙H2O (1∙H2O), [CuClL2]·CH3OH (2·CH3OH) and [Cu2Br2L22(CH3OH)2] (3). The hydrazones and three copper complexes were characterized by physico-chemical methods such as elemental analysis, infrared and electronic spectroscopy. The free hydrazones were also characterized by 1H NMR spectroscopy, and structures of H2L1 and the complexes were further confirmed by single crystal X-ray determination. The hydrazone ligands in the complexes coordinate to Cu ions through phenolate oxygen, imino nitrogen and carbonyl oxygen atoms. The Cu ion in complex 1 is in square planar coordination, in complex 2 is in square pyramidal coordination, and in complex 3 is in octahedral coordination. The complexes show good antibacterial activities on the bacterial strains Bacillus subtilis, Staphylococcus aureus and Escherichia coli, while weak activity on the fungal strain Candida albicans and no activity on Aspergillus niger.

This study investigates the quantitative relationship between the kinetics and thermodynamics of mineral dissolution in heterogeneous reactions, specifically focusing on the dissolution of sparingly soluble minerals. Building on historical developments in chemical kinetics and thermodynamics, we propose empirical equations that describe experimental data and enable predictive modeling of dissolution processes. Two descriptors were evaluated: the normalized Gibbs energy of oxidation (ΔrG⁰/σ) and the average atomic Gibbs energy of mineral formation (ΔfG⁰/n). Experimental values of the apparent rate constant (k) and specific dissolution rate (W) were obtained under strictly controlled conditions. Linear regression models were developed. The regression coefficients were interpreted in terms of reagent selectivity and aggressiveness, consistent with the Bell-Evans-Polanyi principle. These findings support the use of ΔfG⁰/n as a reliable predictor of mineral reactivity and provide a thermodynamic basis for rational selection of leaching agents.

A series of novel 5-((3aR,5S,6S,6aR)-6-((1H-pyrazol-3-yl)methoxy)-2,2-dithyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)-3-(4-fluorophenyl)-6-phenyl-3,3a,5,6-tetrahydrothiazolo[4,5-c]isoxazoles 10a-g were synthesized by the reaction of chalcone derivatives of (E)-2-((3aR,5S,6S,6aR)-6-((1H-pyrazol-3-yl)methoxy)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)-5-(4-fluorobenzylidene)-3-phenylthiazolidin-4-ones 9a-g with hydroxylamine hydrochloride. The chemical structures of newly synthesized compounds were elucidated by IR, NMR, MS and elemental analysis. The compounds 10a-g were evaluated for their nematicidal activity against Dietylenchus myceliophagus and Caenorhabditis elegans, compounds 10b and 10f showed appreciable nematicidal activity.

The present study has employed a combination of UV-Vis, 13C NMR spectroscopic and computational methods to explore the antioxidant interactions between trans-resveratrol and L-ascorbic acid in the reaction with 2,2-diphenyl-1-picrylhydrazyl radical. Significant synergic and antagonistic effects were observed depending on the reaction conditions. Various molar ratios of antioxidants have been tested, and the highest synergistic interaction has been registered for the 1:1 ratio of antioxidants. 13C NMR spectral data argued on the dimerization of resveratrol producing the known natural trans-δ-viniferin as a crucial phenomenon involved in the synergetic antioxidant activity. The Density Functional Theory data completed the research, advancing the possibility of synergistic interactions through the regeneration of resveratrol's and its oligomer's radicals by the ascorbic acid via the hydrogen atom transfer pathway.

In this study, eight QSAR models were constructed to develop novel compounds as tyrosinase inhibitors. The decision tables, Bagging, and Random Committee methods showed the best predictive abilities (q2 ≥ 0.5) among the models. Based on these models, twelve new kojic acid derivatives were synthesized. Tyrosinase inhibition was determined using a spectrophotometric method with L-DOPA as the substrate. Molecular docking studies were conducted to provide insights into the tyrosinase-inhibiting mechanisms of the compounds. Cytotoxic effects on the B16F10 melanoma cell line were investigated using the SRB assay. A melanogenesis assay was also performed to detect the inhibition of melanin production. Compounds 4l, 4j, and 4b exhibited better tyrosinase inhibitory effects than the positive control, kojic acid (218.8 µM), with IC50 values of 138.1, 159.0, and 208.9 µM, respectively. Compound 4j showed the best anti-melanogenesis effect among the compounds tested. These findings demonstrate the potential of the compounds developed as novel tyrosinase inhibitors for clinical and cosmetic applications.

The reactivity of 1-ethyl-1,2-dihydro-4-hydroxy-2-oxoquinoline-3-carbaldehyde (1) towards some diaza-nucleophiles has been investigated, under various reaction conditions. 1-Ethyl-1,2-dihydro-4-hydroxy-2-oxoquinoline-3-carbaldehyde (1) was reacted with hydrazine, phenylhydrazine, 2,4-dinitrophenylhydrazine, acid hydrazides, semicarbazide, thiosemicarbazides, thiocarbohydrazide, ortho-phenylenediamine and ortho-aminophenol. It was found that solvents used in these reactions impacted product selectivity. Accordingly, these reactions led to various open-chain and/or cyclic derivatives of quinolinone. The structure of the new compounds was determined using spectroscopic techniques and elemental analyses. All products were screened in vitro to determine their antimicrobial, antioxidant and antitumor activities. Compounds 2a and 2c are the most active compounds against bacterial and fungal strains. While the most effective compounds against breast cancer (MCF-7) are compounds 2a and 8a.

The chemical stability of active substances affects the safety and efficacy of the drug products. The aim of this study was to investigate the stability and dissolution of paracetamol tablets produced by wet granulation (GS, GP) and direct compression (K). The highest percentage of loss was observed during alkaline hydrolysis (between 10.41% and 16.06%). Acidic conditions caused the highest degradation in sample K (5.3%). Oxidative conditions lead to the highest degradation in two formulations (K, GP). The loss was below 5% after thermal and photolytic degradation for all samples, with the highest decrease found in pure paracetamol after thermal degradation (2.63%). The dissolution profiles best fit to Korsmeyer-Peppas model, with the slowest release observed in formulation K. The study of different formulations revealed a significant influence of formulation factors (producing method, presence of excipients) on the stability and dissolution of paracetamol.

Many complexes have shown antitumor potential, including the bis(S-ethyl-2-thiosalicylate)palladium(II) complex. The aim of this study was to investigate potential immunomodulatory effects of this complex on acquired and innate immunity, in vitro. The effect was assessed based on the levels of cytokines tumor necrosis factor alpha (TNF-α), interleukin (IL) 1β, interferon gamma (IFN-γ), IL-17 and IL-10. Cytokine concentrations were measured by ELISA assay. Pd(II) complex led to a reduced secretion of most pro-inflammatory cytokines. The effects of the complex were more intense in non-activated cells. The same effect was shown in cells of acquired and innate immunity. These effects make the Pd(II) complex not only a potential antitumor agent, but also an anti-inflammatory agent.

Hydrazone compounds have interesting biological activities. In this work, a new hydrazone compound 3,5-dihydroxy-N'-(pyridin-2-ylmethylene)benzohydrazide (HL) was synthesized and characterized by IR, UV-Vis, 1H and 13C NMR spectroscopy. The compound reacts with copper chloride and nickel acetate, respectively, to afford metal complexes [CuCl2(HL)]∙CH3OH (1∙CH3OH) and [NiL2]∙2CH3OH∙2H2O (2∙2CH3OH∙2H2O). The complexes were characterized by elemental analysis, and IR and UV-Vis spectroscopy. Structures of HL and the complexes were further confirmed by single crystal X-ray determination. The hydrazone ligand in complex 1 adopts neutral form and coordinates to Cu ion through pyridine nitrogen, imino nitrogen and carbonyl oxygen atoms. The hydrazone ligands in complex 2 adopt monoanionic form and coordinate to Ni ion through pyridine nitrogen, imino nitrogen and enolate oxygen atoms. The Cu atom in complex 1 is in square pyramidal coordination, and the Ni atom in complex 2 is in octahedral coordination. The compounds were tested for their urease inhibitory activities. Complex 1 has remarkable activity on Jack bean urease (IC50 = 0.5 ± 0.1 μmol L-1).