Bulletin of the Korean Chemical Society最新文献

Amine metabolites play crucial roles in biological systems and serve as biomarkers for various diseases. In this study, we developed a cost-effective derivatization method based on N-tert-butyloxycarbonylation (Boc), which is the most affordable among previously reported amine derivatization methods. This environmentally friendly approach enhances the retention and detection of amine metabolites in reversed-phase liquid chromatography-mass spectrometry, with Boc derivatives demonstrating excellent stability for at least 20 days at 4°C and 60 days at −20°C. Importantly, Boc derivatization does not affect the signal intensity or the number of non-amine metabolites, ensuring the method's compatibility with untargeted metabolomics workflows. The effectiveness of this method was validated using immature rice seed extracts from japonica and indica cultivars. Boc derivatization enabled the signal detection of 54 amine metabolites, with comparative analysis identifying 11 significantly differentiated metabolites between the two rice varieties, including histidine, methionine, pipecolate, and GABA. The specificity and robustness of this method confirm its utility for discovering biologically relevant metabolites in complex biological and agricultural samples. With its simplicity, catalyst-free workflow, stability, and improved sensitivity, the Boc derivatization method represents a valuable tool for amine metabolite screening in metabolomics research, offering a cost-effective and efficient solution for untargeted analysis.

The primary objective of this review is to outline the synthesis of pyrazolines and pyrazoles derived from 1,3-diaryl Prop-2-en-1-ones as crucial precursors and to elucidate their potential biological activities. The diverse synthetic methodologies, including 1,3-dielectrophile cyclization, 1,3-dipolar cycloaddition/1,3-H shift, Michael Addition reactions, [3+2] annulations, intramolecular condensation reactions, Atwal Reactions, and others, have been deliberated upon. Chalcones are considered important compounds because of their ketoethylenic group, and they include a wide array of compounds with various applications. The investigation of the biological evaluation of pyrazoline and pyrazole derivatives has emerged as a convincing area of research within pharmaceutical chemistry. This review may serve as a valuable resource for the development and design of novel, potent therapeutic agents, leveraging previously established strategies.

Metal–organic frameworks (MOFs) offer a versatile platform for immobilizing catalytically active species, enabling diverse organic transformations through their structural tunability and well-defined pore environments. This study investigates the covalent immobilization of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) radicals in Zr-based MOFs, synthesizing six distinct frameworks with varying linkages, including amides, esters, ethers, triazoles, and ureas. The catalytic efficiency of these MOFs was evaluated in the aerobic oxidation of secondary alcohols to ketones, highlighting the role of electronic effects, linker size, and TEMPO radical density. Furthermore, these systems enabled a sequential catalytic process for isoxazole synthesis via cycloaddition, yielding 16 isoxazoles with high efficiency. While Zr-based MOFs exhibited robust performance in the initial oxidation step, their crystallinity degraded under TBN-excess conditions during the cycloaddition step. Ce substitution on MOF structure partially mitigated this structural degradation, demonstrating potential for enhanced recyclability. These findings offer a comprehensive framework for designing TEMPO-immobilized MOFs with improved catalytic versatility and stability in oxidative transformations.

Rylene derivatives are known for their strong fluorescence, large absorption coefficients, and outstanding thermal and photo-stability. We report quantum-mechanical (QM) calculations of various Lumogen® dyes encapsulated within core-stabilized micelles. Theoretical methods were employed to calculate dyes' absorption wavelengths, including time-dependent density functional theory and configuration interaction methods with implicit solvation models. Then, the calculated absorption spectra were compared with experimental ones. We observed absorption wavelength shifts correlated with structural features of dyes and solvents identified from QM calculations and statistical analysis. Such structural insights enabled the prediction of absorption characteristics of rylene-based materials in various dielectric environments by developing regression models.

X-ray imaging transforms battery research, offering multiscale insights into structures, compositions, and electrochemical dynamics. Advanced operando methods visualize real-time changes in batteries non-invasively, overcoming conventional limitations. Progress in resolution and data analytics enables detailed studies of interfaces, phase transitions, and particle heterogeneity, supporting future battery performance improvements can be found in the article by Sebastian Kunze, Chihyun Nam, Hwiho Kim, Jinkyu Chung, Eunki Hong, Jaejung Song, Hanbi Choi, Jongwoo Lim.

Malignant melanoma has the highest mortality rate of any skin cancer due to its aggressive nature and high potential for metastasis, and early diagnosis is critical for improving outcomes because of the limited treatment options available for patients. We synthesized a brominated benzamide derivative labeled with ⁶⁸Ga and evaluated its biological properties as an imaging agent for detecting melanoma using positron emission tomography (PET). The eluted ⁶⁸Ga was dissolved in 1.0 M NaOAc buffer and labeled with the synthesized precursor. The radiochemical yield and radiochemical purity of the ⁶⁸Ga chelation complex were confirmed by radio-thin layer chromatography. In vitro uptake was measured in the murine melanoma cell line (B16F10), and in vivo studies were performed with B16F10-bearing mice. The total radiochemical yield was over 95% (n > 3), and the radiochemical purity was above 98%. The ⁶⁸Ga-labeled compound showed high uptake in B16F10 cells activated with l-tyrosine (2 mM) (6561.48 ± 1067.52 counts per minute [CPM] at 30 min, 8987.03 ± 888.64 CPM at 60 min). The labeled compound allowed visualization of B16F10 xenografts on microPET at 60 min after intravenous injection (tumor uptake: 1.20 ± 0.20% ID/g at 30 min, 0.91 ± 0.24% ID/g at 60 min). These results suggest that ⁶⁸Ga-labeled 2,2′,2″,2‴-(2-(4-(3-(2-((2-(5-bromopicolinamido)ethyl)(methyl)amino)ethyl)thioureido)benzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (⁶⁸Ga-MI-0202E1) has potential as a PET imaging probe for the detection of melanoma.

Heterogeneous single-atom catalysts (SACs) have gained significant attention due to their high catalytic activity and tunable reactivity, which are strongly influenced by the choice of support material. In this study, we employ density functional theory calculations to investigate CO oxidation on Au SACs adsorbed at single-vacancy (SV) sites of various carbon-based materials, including graphene, graphite (Gr), and K-intercalated graphite (K@Gr). Our computational results reveal that K@Gr provides enhanced catalytic stability and activity compared to other carbon-based support materials due to strong electrostatic interactions between intercalated K atoms and the carbon atoms surrounding the Au atom adsorbed at the SV site. The CO oxidation mechanism follows a sequential pathway involving the Langmuir–Hinshelwood and Eley–Rideal mechanisms, in which K@Gr exhibits superior performance in stabilizing key reaction intermediates and thereby provides a more favorable reaction energy profile along the entire reaction pathway. These findings highlight the potential of Gr interaction compounds, such as K@Gr, as promising support materials for SACs, offering both structural stabilization and enhanced catalytic performance through tunable electrostatic interactions.

Ester-to-alcohol reductions under green conditions (low catalyst loadings, solvent-free, room temperature, non-toxic, minimal by-products) are highly desirable in the organic-synthesis field. In this context, we report the use of an aluminum-based catalyst as a highly practical and robust method for hydroborating esters. Lithium diisobutyl-tert-butoxyaluminum hydride (LDBBA), a four-coordinate lithium-ion-based aluminum hydride reagent, significantly reduces esters to their corresponding boronates in the presence of pinacolborane (HBpin) under extremely mild conditions. Furthermore, LDBBA was found to be superior to other examined aluminum hydrides. Gram-scale hydroboration and chemoselective reduction reactions are also reported.

Dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) is a protein kinase that is ubiquitously expressed in human tissues and acts as a master regulator of cell proliferation and differentiation. DYRK1A might be associated with Down syndrome (DS), Alzheimer's disease (AD), autism spectrum disorder (ASD), diabetes and other neurodegenerative diseases. In search of novel and selective DYRK1A inhibitor scaffold, KTD-092 are validated as a hit for DYRK1A inhibition. KTD-092 shows good stability under various liver microsomes, and markedly reduces tau phosphorylation in a human neuroblastoma cell in a concentration-dependent manner. Molecular binding mode of KTD-092 to DYRK1A is also proposed.

In recent years, transition metal-catalyzed reductive alkylation of alkenes has gained attention due to its ability to circumvent the use of unstable organometallic reagents by generating reactive intermediates in situ from stable precursors with enhanced reaction safety and efficiency. This review provides an overview of recent advancements in copper-catalyzed reductive alkylation of alkenes, with a particular focus on the use of hydrosilanes and diborons as stoichiometric reducing agents. Key topics include mechanistic insights, strategies for controlling regio- and stereoselectivity in both intra- and intermolecular alkylation reactions, and innovative catalyst designs for selective product synthesis. Emerging trends such as radical-mediated transformations and contributions from alternative first-row transition metals including nickel and iron are also discussed.