Search Results (60)

Fusarium solani is a major soil-borne pathogen responsible for root rot diseases, posing a significant threat to agricultural productivity. The development of environmentally sustainable alternatives to chemical fungicides is therefore urgently needed. This study evaluated the antifungal activity of fermentation broths and extracellular metabolites derived from Tilletia laevis fungi at different developmental stages against F. solani under in vitro conditions. Six test agents, including carbendazim (one positive fungicide control), caffeic acid, phenylacetylglycine, and 6-hydroxypyridine-2-carboxylic acid (candidate bioactive metabolites), were evaluated for mycelial growth inhibition, EC₅₀ values, and physiological responses. All treatments exhibited concentration-dependent inhibitory effects, with carbendazim showing the highest activity (EC₅₀ = 21.26 mg L⁻¹). Among the metabolites, 6-hydroxypyridine-2-carboxylic acid and phenylacetylglycine demonstrated notable antifungal efficacy, particularly at higher concentrations. Fermentation broths from the promycelial stage showed stronger inhibition than those from the teliospore stage, indicating stage-specific metabolite activity. Biochemical analyses of F. solani mycelia revealed significant changes in soluble protein, soluble sugar, and antioxidant enzyme activities (SOD and POD), suggesting that antifungal effects are mediated through metabolic disruption and oxidative stress. These findings highlight the potential of T. laevis-derived metabolites as eco-friendly biofungicides and provide a theoretical basis for sustainable management of soil-borne diseases. Further studies are required to identify active compounds and validate their efficacy under field conditions. Full article

To develop self-healing polyurethane materials with high transparency and superior mechanical performance, in this work, the poly(thiourethane) elastomers were prepared by incorporating the dynamic thiourethane bonds via thiol–isocyanate click reaction, followed by the addition of 1-(3-aminopropyl)imidazole (IZ), 3-hydroxypyridine (HP), and 2,4-diamino-6-hydroxypyrimidine (HPM) as ligands to produce three different polyurethane networks (named PTU-IZ, PTU-HP, and PTU-HPM). Zinc chloride (ZnCl₂) was further introduced to construct metal-coordinated crosslinking networks, recorded as PTU-IZ-Zn, PTU-HP-Zn, and PTU-HPM-Zn, respectively. The effects of ligands and Zn²⁺ coordination on the materials’ optical transmittance, mechanical properties, self-healing capability, and reprocessability were systematically investigated. The results demonstrate that HPM and Zn²⁺ will facilitate the formation of more effective crosslinking, which significantly enhances the mechanical properties of PTU-HPM from 4.61 MPa up to 9.04 MPa (PTU-HPM-Zn), while maintaining high transparency (89.0% light transmittance at 650 nm). Self-healing tests reveal that the PTU-HPM-Zn scratches can fully repair within 4 h at 70 °C. Reprocessability tests demonstrate that the internal crosslinked network of the material undergoes reversible dissociation, enabling a topological transition from a crosslinked to a linear structure and thereby imparting excellent thermal reprocessability. This study provides novel insights for the design and fabrication of high-performance transparent self-healing polyurethane materials. Full article

The title compound 2-iodopyridin-3-yl acetate was obtained by acetylation of the OH group of 2-iodo-3-hydroxypyridine. Knowing that the hydroxyl group, as a strong H-bond donor in halogenated hydroxypyridines, usually directs supramolecular packing and might enforce possible halogen–halogen contacts, we crystallized 2-iodo-3-acetoxypyridine with the aim of disrupting the most important H-bond donor and assessing the propensity of the iodine for halogen bond formation. Indeed, in the compound 2-iodopyridin-3-yl acetate, the crystal packing is characterized by infinite 3D chains bonded through I···O=C and C-H···I contacts between adjacent molecules. These chains are interconnected by weak C-H···O contacts, implying the presence of oxygen in the ester. The I···H contact with the C-H axis perpendicular to the electron belt of the iodine atom can enhance the σ-hole of the iodine and act cooperatively in crystal cohesion. No halogen–halogen contacts were present. Full article

We report an efficient and transition-metal-free protocol for the propargylation of 4-(4-chlorophenyl)-2-oxo-6-phenyl-1,2-dihydropyridine-3-carbonitrile using propargyl bromide in the presence of cesium carbonate in dimethylsulfoxide under mild conditions. This synthetic transformation proceeds with marked chemoselectivity, furnishing the O-propargylated pyridine and the N-propargylated 2-pyridone in 75% and 8% yields, respectively. Both products were fully characterized by IR and NMR spectroscopy, as well as high-resolution mass spectrometry, confirming their molecular structures. Full article

In dynamic equilibria, benzylsilicon pyridine-2-olate (BnSi(pyO)₃, L) and benzaldehyde react with addition of the Si(pyO) moieties to the PhHC=O carbonyl group and formation of compounds BnSi(–O–C(H,Ph)–N^(2-pyridone))_x(pyO)_3−x (L’, L’’, and L’’’, for x = 1, 2, 3, respectively). Addition of CuCl to a solution containing L, L’, L’’, and L’’’ results in the formation of BnSi(pyO)₃CuCl (LCuCl), shifting the equilibrium towards L with liberation of benzaldehyde. In THF as a solvent, the reaction of L in the presence of excess CuCl affords the complex LCuClCuCl. Upon dissolving in chloroform, it transforms into LCuCl with precipitation of CuCl. The solid state structure of LCuClCuCl features both the monomeric complex with CuClCuCl pattern and a dimer thereof with CuClCu(Cl)₂CuClCu pattern and a central Cu₂Cl₂ four-membered ring. This dimer of LCuClCuCl is the first crystallographically characterized representative of this Cu(I)-only Cu₄Cl₄ motif. The reaction of LCuCl and silver tosylate (AgOTos) in THF affords LCuOTos with precipitation of AgCl, whereas LAgOTos was obtained from L and AgOTos. In the crystal structure, LAgOTos features tetracoordinate Ag(I) in a distorted tetrahedral AgN₃O coordination sphere and a short Ag···Si trans-annular contact (3.3245(7) Å). ¹⁰⁹Ag NMR spectroscopy indicates a change in the coordination in solution, with δ ¹⁰⁹Ag = +551 and +419 ppm in the solid and in CDCl₃ solution, respectively. In combination, ²⁹Si NMR spectroscopy indicates changes in the Si coordination sphere, with δ ²⁹Si = −74.2 and −66.5 ppm in the solid and in CDCl₃ solution, respectively. Conversion of LAgOTos with tetraethylammonium chloride results in the precipitation of AgCl with release of L. Full article

In 2019, carbamates derived from 3-hydroxypyridine were classified as nerve agents and subsequently included in the Annex on Chemicals by the Conference of the States Parties. Herein, we describe the preparation of a structural simulant of this class of compounds, 10-hydroxy-N,N-dimethyl-N-((3-(tosyloxy)pyridin-2-yl)methyl)decan-1-aminium bromide. The compound was synthesized via tosylation of 2-((N,N-dimethylamino)methyl)pyridin-3-ol with tosyl chloride in the presence of sodium hydride, followed by alkylation of the resulting ((N,N-dimethylamino)methyl)pyridin-3-yl 4-methylbenzenesulfonate with 10-bromodecan-1-ol. Full article

Lanthanide-based single-molecule magnets (Ln-SMMs) showing stimuli-responsive changes in photoluminescence (PL) and magnetic properties are attractive for their potential applications in information storage and molecular devices. In this work, we report two mononuclear complexes, namely, Dy(SCN)₂(NO₃)(Cl-depma)₂(4-hpy)₂ (Dy-Cl) and Dy(SCN)₂(NO₃)(Br-depma)₂(4-hpy)₂ (Dy-Br), where X-depma represents 10-X-9-diethylphosphinomethylanthracene (X = Cl, Br) and 4-hpy is 4-hydroxypyridine. Both contain face-to-face π-π-interacted anthracene rings and exhibit yellow-green excimer emission. Unlike the other related Dy–anthracene complexes without a halogen substituent, Dy-Cl and Dy-Br cannot undergo photocycloaddition reaction under UV-light irradiation. However, they exhibited remarkable grinding-induced changes in luminescence. Magnetic studies revealed that Dy-Cl and Dy-Br show SMM behavior under zero dc field with the effective energy barriers (U_eff/k_B) of 259 K and 264 K, respectively. We also investigated the effect of pressure on the magnetic properties of Dy-Br and observed a reduction in the magnetization value, narrowing of the butterfly-shaped hysteresis loop, and acceleration of the magnetic relaxation under 1.09 GPa. The results demonstrate that introducing a halogen substituent into an anthracene group may pose significant influences on the photophysical and photochemical properties of the complexes. In addition, pressure may be a promising external stimulus to modulate the PL and SMM behaviors of Dy–anthracene complexes. Full article

The reaction of CoCl₂ · 6H₂O with 6-chloro-2-hydroxypyridine (Hchp) and 1,10-phenanthroline (phen) afforded the complex [Co(chp)₂(phen)] (1). Although this complex has been previously reported, it was obtained in this work under mild conditions (in acetonitrile at room temperature) and characterized for the first time by single-crystal X-ray diffraction. The use of Co(F₃CCOO)₂ · 4H₂O under similar conditions yielded a new trinuclear molecular complex [Co₃(chp)₂(F₃CCOO)₄(phen)₂] (2). According to X-ray diffraction data, the cobalt(II) ions in complexes 1 and 2 are located in an octahedral environment (coordination number CN_Co = 6). As an ambidentate ligand, Hchp exhibits different types of coordination modes in the resulting complexes 1 and 2. Additional stabilization of molecules in the crystal is achieved by π-π stacking between aromatic systems of coordinated phen ligands. The cytotoxic activity of 1 and [CoCl₂(phen)₂] · 1.5MeCN (3) against a panel of human cancer cell lines (SKBR3, HCT116, A549) and normal dermal fibroblasts (HDF) was evaluated using the MTT assay. Complex 3 demonstrated cytotoxic activity against the HCT116 cell line comparable to that of cisplatin, indicating its potential as a promising antitumor agent. Full article

The endometrial immune response in postpartum cows is key to maintaining uterine health and preventing inflammatory diseases such as metritis and endometritis. Appropriate management strategies and diets that enhance the immune response are crucial during the transition period; therefore, diets rich in omega-3 fatty acids have been proposed for their potential beneficial effects on cows. Docosahexaenoic acid (DHA) is an omega-3 fatty acid with anti-inflammatory effects in immune cells; however, its effects on bovine endometrial immunity are not fully known. This study aimed to determine the effect of DHA on the inflammatory response in bovine endometrial (BEND) cells. BEND cells were incubated with DHA without or with lipopolysaccharide (LPS), and the mRNA expressions of prostaglandin-endoperoxide synthase 2 (PTGS2), interleukin (IL)-6, and CXCL8 were analyzed using RT-qPCR. The protein amount of IL-6, or CXCL8, and Resolvin D1 (RvD1) in the cell culture medium were analyzed using ELISA. DHA significantly reduced the expression of LPS-induced IL-6 and PTGS2 but increased LPS-induced CXCL8 expression. In addition, DHA reduced LPS-induced ERK1/2 and Akt phosphorylation, as assessed by immunoblotting. DHA increased the production of RvD1, a metabolite of DHA, at 8 and 24 h. In addition, RvD1 reduced LPS-induced CXCL8 production and increased the phosphorylation of ERK1/2 and Akt. Finally, changes in metabolite levels, such as an increase in 2-hydroxypyridine in DHA-treated cells, were obtained using a metabolomic assay. In conclusion, DHA reduced IL-6 and PTGS2 mRNA expression and IL-6 protein release and increased RvD1 levels in bovine endometrial cells, which suggest that DHA could have beneficial effects on endometrial immunity. The increase in CXCL8 mRNA expression and protein release induced by DHA remains to be studied; however, it could play a role in the innate defensive mechanisms of phagocytes. Full article

The efficient recovery of rhenium (Re), a critical metal in high-tech industries, is essential to address its growing demand and reduce reliance on primary mining. In this study, we developed novel anion-exchange resins for the selective adsorption and recovery of Re(VII) ions from acidic solutions, simulating industrial by-products. The resins were synthesized from a vinylbenzyl chloride-co-divinylbenzene copolymer modified with aliphatic, heterocyclic, and aromatic weakly basic amines, selected from among bis(3-aminopropyl)amine (BAPA), 1-(2-pyrimidinyl)piperazine (PIP), thiosemicarbazide (TSC), 2-amino-3-hydroxypyridine (AHP), 1-(2-hydroxyethyl)piperazine (HEP), 4-amino-2,6-dihydroxypyrimidine (AHPI), and 2-thiazolamine (TA). The adsorption of Re on BAPA, PIP, and HEP resins obeyed the Langmuir model, and the resins exhibited high adsorption capacities, with maximum values reaching 435.4 mg Re g⁻¹ at pH 6. Furthermore, strong selectivity for ReO₄⁻ ions over competing species, including Mo, Cu, and V, was noted in solutions simulating the leachates of the by-products of Cu-Mo ores. Additionally, complete elution of Re was possible. The developed resins turned out to be highly suitable for the continuous-flow-mode adsorption of ReO₄⁻, revealing outstanding adsorption capacities before reaching column breakthrough. In this context, the novel anion-exchange resins developed offer a reference for further Re recovery strategies. Full article

Consumers prefer mung beans for their low allergenicity and nutritional benefits. However, flavour development in mung bean foods has been problematic, with beany flavour being a limiting factor. Hot processing is crucial in forming mung bean flavours, and storage-induced changes in flavour precursors directly impact the taste post-processing. This study used metabolomics to analyse the effects of hot processing (baking and cooking) on mung bean flavour and differences after storage. A total of 131 flavour precursors and 45 volatile substances were identified across six sample groups. The results showed that baking and cooking upregulated 22 and 18 volatile substances (ketones, aldehydes, esters, pyridine, pyrazines, etc.), respectively. The Maillard reaction during baking notably increased compounds like 2-hydroxypyridine, 2-methoxy-3-isobutyl pyrazine, 1,2-hexanedione, and 2,3-butanedione. Both methods inhibited linoleic acid oxidation, significantly reducing hexanal content, a key “bean” odour substance. However, storage accelerated linoleic acid conversion to C13 peroxides, increasing hexanal content and bean odour. This process decreased precursor substances like glucose-1-phosphate and caused the accumulation of pyruvic acid intermediates in pentose phosphate and pyruvate metabolism/amino acid metabolism pathways, leading to reduced mung bean taste richness. Full article

Monomers of N-hydroxypyridine-2(1H)-thione were isolated in low-temperature matrices of solid normal hydrogen (n-H₂). The matrix-isolated compound was irradiated with UV-B (λ = 305 nm) or UV-A (λ > 360 nm) light. Upon such irradiation, the initial form of N-hydroxypyridine-2(1H)-thione was completely consumed and converted into photoproducts. 2-Mercaptopyridine and water were identified as the main products of these photochemical transformations. Identification of photoproduced 2-mercaptopyridine is unquestionable. It is based on the identity of two sets of IR bands: (i) the bands observed in the IR spectrum recorded (in a separate experiment) for monomers of 2-mercaptopyridine trapped in an n-H₂ matrix and (ii) a set of IR bands observed in the spectrum recorded after UV irradiation of N-hydroxypyridine-2(1H)-thione. It should be emphasized that the UV-induced processes, occurring for N-hydroxypyridine-2(1H)-thione isolated in an n-H₂ matrix, lead to products that are significantly different from those generated from the compound trapped in solid Ar or in solid N₂. Full article

Two new paddlewheel-type dirhodium (Rh₂) complex isomers, formulated as trans-2,2- and 3,1-forms of [Rh₂(bhp)₄] (bhp = 6-bromo-2-hydroxypyridinate), were obtained by the reaction of 6-bromo-2-hydroxypyridine with [Rh₂(O₂CCH₃)₄(H₂O)₂] and characterized by NMR, ESI-MS, and elemental analyses. Single crystal X-ray diffraction analyses clarified that the crystal structure of trans-2,2-form takes a conventional paddlewheel-type dimer structure with no axial coordination ligands, i.e., trans-2,2-[Rh₂(bhp)₄], whereas that of the 3,1-form changed significantly depending on the kinds of solvent used for crystallization processes; dimer-of-dimers-type tetrarhodium complex, i.e., 3,1-[Rh₂(bhp)₄]₂, and a conventional paddlewheel-type dimer complex with an axial DMF ligand, i.e., 3,1-[Rh₂(bhp)₄(DMF)], were observed. The 3,1-form showed unique absorption changes that were not observed in the trans-2,2-form; the trans-2,2-form showed an absorption band at approximately 780 nm both in the solid state and in solution (CH₂Cl₂ and DMF), whereas the 3,1-form showed a similar absorption band at 783 nm in CH₂Cl₂ solution, but their corresponding bands were blue-shifted in solid state (655 nm) and in DMF solution (608 nm). The molecular structures and the origin of their unique absorption properties of these Rh₂ complexes were investigated using density functional theory (DFT) and time-dependent DFT (TDDFT). Full article

2-Hydroxypyridines (or commonly named 2-pyridones) are widespread nitrogen heterocycles in natural and synthetic products and their applications in biological, pharmaceutical and agrochemical compounds are becoming increasingly important. Therefore, several procedures have been described in the literature for the preparation of this heterocyclic framework. Among them, multicomponent reactions are the currently practiced method in synthetic organic chemistry, where reduced reaction times, high yields, and ease of product isolation are the main benefits of this method. In order to study the effect of the aforementioned method under greener medium, we herein describe a novel one-pot route for the design of 4,6-diaryl-3-cyano-2-pyridone derivatives under free solvent conditions. The three-component condensation of alkenes, ketones, and ammonium acetate efficiently resulted in the target heterocycles, with higher yields within a short time reaction compared to the classical method. Full article

2-Ethyl-6-methyl-3-hydroxypyridine succinate (EMHPS, Mexidol) is an original antioxidant and an anti-ischemic drug with the possibility of wide applications in the complex therapy of diseases, accompanied by the development of oxidative stress and ischemia; for example, ischemic stroke, chronic cerebral ischemia, and chronic heart failure. The use of EMHPS in the complex therapy of the above diseases may cause the development of drug–drug interactions, particularly pharmacokinetic interactions at the level of transporter proteins. In the present study, we evaluated the interaction of EMHPS with ABCB1 and SLCO1B1. In Caco-2 cells, it was shown that EMHPS is not a substrate of ABCB1 and that it does not affect its expression, but at the same time, it inhibits the activity of this transporter. Its inhibitory activity was inferior to verapamil—a classic inhibitor of ABCB1. In HEK293 and HEK293-SLCO1B1 cells, it was shown that EMHPS is not a substrate of SLCO1B1 either, but that it inhibited the activity of the transporter. However, its inhibitory activity was inferior to the classic inhibitor of SLCO1B1-rifampicin. Furthermore, it was found out that EMHPS does not affect SLCO1B1 expression in HepG2 cells. The approach proposed by the FDA (2020) and the International Transporter Consortium (2010) was used to assess the clinical significance of the study results. The effect of EMHPS on SLCO1B1 and the systemic inhibition of ABCB1 by EMPHS are not clinically significant, but ABCB1 inhibition by EMHPS in the gastrointestinal tract should be tested in vivo through clinical trials. Full article