Chemistry and Materials Science

Abstract: A novel chiral three-dimensional conjugated polymer with aggregation-induced emission (AIE) was constructed via asymmetric Suzuki–Miyaura cross-coupling polymerization. Comprehensive photophysical characterizations confirmed its stable AIE activity, excitation-tunable luminescence, and solvatochromism in biomimetic media including water, simulated body fluid, and simulated urine. Ion sensing studies revealed that the chiral framework specifically chelates Ag⁺ through multiple coordination sites, producing significant fluorescence enhancement with a linear response from 0–900 μM and a micromolar detection limit, alongside excellent anti-interference capability. The material also exhibits differentiated dual-channel optical responses toward Fe³⁺ and Cr⁶⁺. Electrochemical analysis elucidated an electron-rich conjugated backbone, supporting a charge-transfer-mediated recognition mechanism. Benefiting from its unique multilayer three-dimensional cavity topology, the polymer demonstrates superior ion capture capacity and specificity over conventional linear or monolayer systems. This work presents a new molecular design strategy for high-performance fluorescent probes, with substantial practical potential for environmental and biological monitoring applications such as industrial wastewater treatment, surface water heavy-metal screening, and trace ion analysis in biological fluids.

Abstract: In the present work, we report the sustainable regioselective synthesis of a novel series of 1,2,3-triazole-based hybrid molecules containing isatins and 1,4-dihydropyridines by Copper(I)-catalyzed Azide-Alkyne 1,3-dipolar Cycloaddition (CuAAC). We designed and realized these hybrid molecules with the idea to produce multitarget agents with poten-tially improved bioactivity, enhanced pharmacokinetic properties and a reduced risk of drug resistance. Our synthetic strategy provides mild reaction conditions, high reaction yields, a simple recover procedure and a reusable catalytic system based on an environ-mentally benign solvent mixture of ionic liquid/water. The latter was recovered together with the Cu(I) catalyst generated in situ and Na-ascorbate and reused until six times, maintaining high efficacy in terms of regioselectivity and reaction yields. Finally, a mech-anism of the reaction was proposed, involving the key role of IL.

Abstract: Betulin, a lupane-type pentacyclic triterpene abundant in birch bark, is a useful natural scaffold for semisynthetic medicinal chemistry and process-oriented natural product chemistry. This review examines betulin 3,28-diacetate as an important derivative that is readily prepared, easily purified as a crystalline compound, and useful both as a target molecule and as a protected intermediate for further functionalization. The article surveys three connected areas: access to betulin from birch biomass, acetylation methods at labor-atory and process scale, and the synthetic utility of the diacetate in preparing more ad-vanced lupane derivatives. It summarizes extraction, purification, and analytical charac-terization of betulin, including melting-point analysis, chromatography, IR spectroscopy, NMR spectroscopy, and mass spectrometry. The review also compares classical acetyla-tion using acetic anhydride and acid catalysts with base-mediated approaches and green-er or more process-relevant variants, including direct bark acetylation and supercritical carbon dioxide-assisted isolation. Overall, betulin 3,28-diacetate is a practical and versa-tile intermediate for access to monoacetates, oxidized derivatives, and other lupane com-pounds, while further progress depends on improved catalyst choice, solvent replacement, process intensification, and analytical standardization.

Abstract: The consistent increase of atmospheric CO₂ concentration, mostly driven by the global combustion of fossil fuels, is nowadays considered the major contributor to making many environmental challenges much more severe, like climate change and global warming. Attending to this issue requires innovative strategies that transform CO₂ into a valuable resource. In this work, we report a sustainable and fully metal-free approach for the synthesis of cyclic carbonates via the direct coupling of CO₂ with epoxides, using natural sugars as readily available, non-toxic organocatalysts in combination with tetrabutylammonium iodide (TBAI) as cocatalyst. Seven representative mono- and disaccharides were screened employing styrene oxide as a model substrate under mild reaction conditions (80 °C, 20 bar CO₂, 2 h). Among them, D-xylose exhibited the best catalytic performance. The robustness of this catalytic system was further demonstrated through the efficient transformation of a wide range of terminal, internal, and biomass-derived epoxides into their corresponding cyclic carbonates with high yields and selectivity (up to 99%). Additionally, a set of computational simulations based on density functional theory (DFT) calculations was carried out to gain insight into the atomistic mechanisms involved in this chemical transformation. We identified that the hydroxyl groups of the sugar catalyst play a pivotal role in activating the epoxy ring-opening process, leading to cyclic carbonate formation. This bio-inspired strategy provides a green, cost-effective, and scalable pathway to produce key precursors for organic chemistry, contributing to the development of a circular carbon economy and the advancement of sustainable chemistry.

Abstract: The enantiomeric composition of products obtained from isomerization of n-humulone 1a to trans- and cis-n-isohumulones 2a and 3a, respectively, was determined by chiral HPLC analysis of the isolated trans and cis isomers. Enantiomers of humulones 1 were readily resolved on a Whelk-O1 chiral stationary phase (CSP), whereas the isomeric isohumulones 2 and 3 were separated on a carbohydrate based IC-3 CSP. Magnesium catalyzed isomerization of n-humulone under basic conditions gave mixtures or trans- and cis-n-isohumulones exhibiting an increasing preference for the cis isomer at lower temperatures. At either 10 oC in CH2Cl2/H2O or reflux in methanol-water, the trans-(-) (4S,5S)-2a isomer was obtained in greater than 95% ee, while cis-3a exhibited 88% ee of the (+)-(4S,5R) enantiomer. Precision continuous flow photochemical isomerization using 395 nm LEDs provided trans-(-)-2a in greater than 95% ee in an isolated yield of 93%. However, photochemical isomerization with 365 nm LEDs gave a mixture of isomers consisting of 46% ee for the trans-(-)-2a and greater than 95% ee for the cis-(-)-(4R,5S)-3a enantiomer. The photochemically obtained (-)-3a isomer has the opposite absolute configuration compared to thermal isomerization. An oxadi-π-methane rearrangement is proposed to account for the formation of isohumulone isomers under photochemical conditions.

Abstract: This review covers published data (mostly from 2019–2025) on the synthesis and biological activity of azolo[a]quinoxalines, including pyrazolo-, imidazo- and triazolo-annelated systems. We highlight that most research efforts are directed toward the design of anticancer agents, with additional applications as Toll like receptor antagonists, monoamine oxidase inhibitors, opioid receptor modulators, PI3Kα inhibitors, tubulin polymerization inhibitors, GABAᴀ receptor modulators, VEGFR 2 kinase inhibitors, BRD9 binders, and anti inflammatory, antimicrobial, and antifungal agents. Recent synthetic strategies include Cu catalyzed oxidative annulations, I₂ mediated C–H functionalization, metal free cascade cyclization, and multicomponent reactions, often employing eco friendly catalysts and reductants. A growing number of studies integrate virtual screening, molecular docking, and pharmacophore based in silico approaches to guide lead discovery and optimization. Innovative drug delivery systems, such as nanogels, and hybrid molecules combining azoloquinoxalines with pharmacophores like thalidomide have also been explored. This review emphasizes both the medicinal chemistry aspects of azolo[a]quinoxalines and the synthetic methodologies for their preparation, in the perspective of drug development and discovery.

Abstract: The target (1E,4E)-1,5-bis(2,4-dichlorophenyl)penta-1,4-dien-3-one oxime 4 was prepared in good yield, as a key aza-precursor for the Nazarov cyclization, through a two-steps sequence. Initially, the starting divinyl ketone 1a was obtained from a Claisen-Schmidt condensation reaction between 2,4-dichlorobenzaldehyde 3 and acetone in the presence of aqueous 20% NaOH. Subsequently, treatment of 1a with hydroxylamine hydrochloride under thermal conditions afforded the expected oxime in excellent yield whose structure was confirmed by analytic and spectroscopic techniques.

Abstract: A series of cis-5-arylmethyl-2-alkyl-3-methylimidazolidin-4-ones, prepared from arylmethyl-substituted α-amino acids, and a series of trans- and cis-2-(fluoromethyl)-2,3-dimethylimidazolidin-4-ones, derived from L-valine and L-leucine, were synthesized and fully characterized. Their catalytic activity was evaluated in the addition of 1-methylindole to cinnamaldehyde. Using the cis-5-arylmethyl-2-alkyl-3-methylimidazolidin-4-one catalysts, enantioselectivities of up to 78% ee (S) were achieved. Notably, with the L-valine-derived cis-imidazolidinone organocatalyst, the highest reversal of stereoselectivity to date (92% ee, (R) at –43°C) was observed.

Abstract: The isoxazole-5-one ring system is a central structure in many synthetic bioactive molecules, showing a wide range of biological activities, including antibacterial, antitumor, anticorrosion, antifungal, antituberculosis, and antioxidant. They are also applied as agrochemical having potential fungicide effects. Given various applications, these pharmaceutically and biologically significant heterocyclic compounds have attracted great attention of the chemistry synthetic researchers. This study aimed to investigate application of glycerol as a reaction medium for the three-component synthesis of arylidenisoxazol-5(4H)-one derivatives. The results of the optimized investigations revealed that 3.0 mL glycerol is the best reaction medium. Evaluation effect of reaction temperature showed that the best temperature for this strategy is 60 °C. In the present environmental friendliness study, the desired heterocyclic compounds were quickly synthesized via a one-pot three-component reaction of two keto-esters with hydroxylamine hydrochloride and a number of aryl/heteroaryl aldehydes. This synthetic approach has significant merits, such as cost-effectiveness of reaction medium, rapid green synthesis, operational simplicity, easy workup, avoid chromatographic purification, sustainability, acceptable yields, relatively inexpensive as well as commercially available starting materials.

Abstract: Despite being discovered over a century ago, lathyrane diterpenoids have only recently attracted significant attention from the organic chemistry community due to their distinctive carbon framework, characterized by a 5/11/3 tricyclic system. The conformational rigidity of these scaffolds promotes close spatial proximity between functional groups, making transannular reactions a powerful tool for the construction of new complex polycyclic architectures. In parallel, compounds from the genus Euphorbia have emerged as privileged scaffolds in medicinal chemistry, exhibiting a wide range of biological activities, including cytotoxic, antiviral, and neuroprotective effects. This review summarizes recent advances in the field, with particular emphasis on synthetic strategies, structural diversity, and medicinal chemistry aspects of this intriguing class of secondary metabolites.

Abstract: This review intends to provide an insight into the wide range of possibilities for vegetable oils to be used as solvents to extract natural ingredients for various applications with special emphasis on antioxidants. The potential of using oils as food-grade solvents for extraction of carotenoids, crocins, curcuminoids, cannabinoids, capsaicinoids, different volatile organic compounds and other lipid-soluble phytochemicals from plant sources and by-products is summarized. Most studies focus on optimizing extraction parameters and evaluating the physical and chemical characteristics of the obtained oily plant extract. On the one hand, these infused or enriched oils can be considered as plant extracts, but, on the other hand, one should not ignore the fact that lipid oxidation is a problem that needs to be addressed. The characterization and analysis of the obtained oily extracts is closely related to their specific application in the food or cosmetic industry. Despite all the advantages, disadvantages related to the stability of the fortified oils are discussed as well.

Abstract: Hydrogen energy is considered to be an ideal energy source for the 21st century due to its clean and renewable nature. However, the large-scale application of hydrogen has been hindered by challenges in storage and transportation. Therefore, the development of safe and cost-effective hydrogen storage materials remains a key focus of current research. Metal-organic frameworks (MOFs) are a novel class of porous materials that can be customized to have different pore sizes. They also feature an ultrahigh surface area, impressive porosity, and excellent thermal and chemical stability. Because of these qualities, MOFs show great promise for hydrogen storage applications. This article provides a comprehensive review of the advancements in hydrogen storage research within MOFs, and examines the factors governing hydrogen storage performance, with particular attention to factors such as metal ion selection, pore architecture, ligand functionalization, and temperature effects. In addition, the article points out the main challenges faced by MOFs in hydrogen storage applications, including high synthesis costs, challenges in large-scale production, and limited structural stability. Finally, it looks ahead to the prospects of MOFs as hydrogen storage materials under mild conditions.

Abstract: Fluorinated isoquinoline-1,3-diones possess important biological activities and application value in many fields such as medicine, pesticides, and organic synthesis.This review summarizes the synthetic methods of fluorinated isoquinoline-1,3-diones in recent years，mainly including traditional synthesis methods，visible light catalysis， electroorganic synthesis. Moreover, the advantages and disadvantages of these methods are discussed. In this review, these synthetic methods are summarized, in order to provide a reference for the design and research of these compounds. Future perspectives on method development are also briefly considered.

Abstract: Herein, Diacetylcurcumin (DAC), a derivative of curcumin, was synthesised, and two new polymorphs (monoclinic and triclinic) are reported in addition to the previously known polymorph (P2₁). Solid-state NMR (CP-MAS) and X-ray studies allowed the unambiguous authentication of the elusive polymorph 2 (canoe-shaped, P2₁/n) and the concomitant polymorph 3 (elliptical-shaped, P-1). We demonstrate that morphological crystal analysis under a microscope, in conjunction with ATR-IR, is a rapid and inexpensive technique for exploring the polymorphic landscape of curcuminoids. This discovery highlights the ongoing progress in curcumin derivative research and should inspire fellow chemists and materials scientists to further explore it.

Abstract: Hysteresis is normally unavoidable in hydrogels under complex external loading conditions due to the intermolecular friction, which usually leads to fatigue. Here, we develop a sarcomere-inspired double-network hydrogel made from polyacrylamide, alginate and phytic acid, whose hysteresis can be precisely modulated by preloading. Particularly, due to the synergy of micellization, fibrillation and micro-lubrication, the as-prepared hydrogel displays an ultra-low hysteresis (≤ 0.02 %) after it experiences a pre-tensile process at a specific amplitude and strain rate, or even possesses negative hysteresis in the case of low tensile amplitudes or high strain rates. Interestingly, smart responses of the developed hydrogel to cyclic tensile loadingare similar to the mechanical behaviors of sarcomeres in vivo. Likewise, the derived hydrogel with ultra-low hysteresis performs reliably even at temperatures as low as -20 ℃. The ultra-low hysteresis presented by the biomimetic hydrogel with ultra-low hysteresis makes it suitable for many engineering fields like electrical sensing with superior reliability (the corresponding electrical signal (ΔR/R0) is stable even after 1000 stretching-unstretching cycles). Moreover, the design strategy of hydrogels with programmable hysteresis provides an innovative methodology for the future development of smart high-performance hydrogels.

Abstract: The title compound 3-(diphenylamino)-4-ethoxycyclobut-3-ene-1,2-dione (6), was prepared by reaction of diphenylamine (2) with diethyl squarate (DES; 5) as part of our ongoing studies on monosquarate-amides. Following purification and recrystallisation, the product was isolated as a green crystalline solid. Its structure was established by spectroscopic methods including: FTIR, ¹H NMR, ¹³C NMR and HRMS and was unambiguously confirmed by single crystal X-ray diffraction. This work provides access to a previously unreported diphenylamino substituted squaric acid derivative.

Abstract: Chirality has emerged as a critical determinant in the design, efficacy, and environmental behavior of modern insecticides. While a significant proportion of agrochemicals are inherently chiral, most are still commercialized as racemic mixtures, despite well-documented differences in biological activity, toxicity, and degradation pathways between enantiomers. In this review, we provide a comprehensive and critical analysis of advances in the stereoselective synthesis and resolution of chiral insecticides, with particular emphasis on neonicotinoids, pyrethroids, and oxadiazines, including indoxacarb. A systematic survey of the literature (1985–2025), including peer-reviewed articles and patents, reveals that multiple strategies have been developed to access enantiomerically enriched compounds, including asymmetric organocatalysis, transition-metal catalysis, chiral-pool approaches, biocatalytic transformations, and chromatographic resolution techniques. Among these, recent developments in photoredox catalysis, recyclable metal complexes, and enzyme-mediated processes have significantly improved enantioselectivity and scalability, bridging the gap between academic methodologies and industrial applications. Despite these advances, challenges remain in achieving cost-effective, sustainable, and universally applicable asymmetric processes. Importantly, the relationship between stereochemistry and biological performance underscores the need for integrating synthetic chemistry with toxicological and environmental studies. Future directions point toward the incorporation of green chemistry principles, continuous-flow processes, and computational tools, including machine learning and molecular modeling, to accelerate the rational design of enantiopure agrochemicals. This review highlights both the progress achieved and the critical gaps that must be addressed to realize the potential of stereoselective insecticide development fully.

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Fluoroalkyl-substituted organoboron compounds are valuable building blocks for organic synthesis and for the development of functional molecules in medicinal chemistry, agrochemicals, and materials science. Building on our previous work on difluoromethyl-substituted borates, we report the synthesis and structural characterization of trifluoromethylated borates, 4,4,5,5-tetramethyl-2-aryl-2-(trifluoromethyl)-1,3,2-dioxaborolan-2-uide salts ([pinB(Aryl)CF₃]^–). Treatment of pinB–Aryl boronates (pinB = 4,4,5,5-tetramethyl-1,3,2-dioxaborolane) with trimethyl(trifluoromethyl)silane (Ruppert–Prakash reagent) in the presence of potassium tert-butoxide and 18-crown-6 (18-cr-6) afforded the corresponding trifluoromethylated borates as isolable crystalline compounds. Compared with the related difluoromethylated borates, the CF₃ substituent increases the tendency of [pinB(Aryl)CF₃]^– to exhibit hygroscopic behavior, as supported by a hydrated crystal structure and the formation of a hygroscopic product. The isolable trifluoromethylborates can serve as reservoirs of electrophilic trifluoromethyl radicals upon oxidation.

Abstract: The formation of side products is often unavoidable in organic synthesis; however, analyzing these secondary species provides practical insights into reaction pathways, mechanisms, and competing processes. This understanding is essential for optimizing reaction conditions, increasing product yields, and improving overall safety and efficiency. Additionally, side products can sometimes reveal unexpected molecular structures with valuable properties. In this study, we present the characterization of a compound that formed as a side product in a modified Pictet-Spengler reaction. The molecular structure of 2,2′-(methylenebis(3,4-dimethoxy-6,1-phenylene))diacetic acid was elucidated using a combination of NMR, FTIR, UV–Vis, and HRMS spectroscopic techniques.

Abstract: The synthesis of hydroxamic acids from sterically hindered substrates, such as abietane-type resin acids, remains a significant challenge due to the extreme congestion of the tricyclic skeleton. This study reports an efficient one-pot protocol for the direct conversion of abietic and dehydroabietic acids into their corresponding hydroxamic derivatives, achieving 65% and 74% isolated yields, respectively. Systematic screening of activating agents identified diethyl chlorophosphate (DCP) as the superior reagent for the hydroxy-amidation. A critical finding of this work is that the optimization of the isolation process specifically minimizing the water amount during aqueous work-up was essential to recover these polar products and prevent significant yield loss. The reaction proceeds through diethyl phosphate mixed anhydride intermediate, which was successfully isolated, providing direct experimental evidence of the activation pathway. The reaction mechanism was further elucidated using density functional theory (DFT) calculations at the M062X/6-31G** level, identifying a concerted transition state for the simultaneous addition of hydroxylamine and expulsion of the phosphate group. Furthermore, the study rationalizes the observed chemoselectivity: although the ester is the more stable thermodynamic product, the formation of the N-hydroxy amide is kinetically favored through a substantially lower activation barrier. This combined experimental and theoretical approach establishes a robust and scalable methodology for the functionaliza-tion of abundant similar natural terpenoids.