Synthesis and characterization of a isothiouronium-calix[4]arene derivative: self-assembly and anticancer activity

• Giuseppe Granata,
• Loredana Ferreri,
• Claudia Giovanna Leotta,
• Giovanni Mario Pitari and
• Grazia Maria Letizia Consoli

Beilstein J. Org. Chem. 2025, 21, 2535–2541, doi:10.3762/bjoc.21.195

• 786O cells, through evaluation of proliferative kinetics with the acridine orange staining assay [45]. The 786O cell line is a widely used in vitro model for studying clear cell renal cell carcinoma (ccRCC) [46], which accounts for over 90% of all renal malignancies and is characterized by poor

• kinetics in renal cancer 786O and skin fibroblast WS1 cells. Data represent the percentage of proliferation with respect to the correspondent vehicle DMSO controls. ***, p < 0.001 vs the respective vehicle control by 2-way ANOVA; ###, p < 0.001 vs correspondent WS1 conditions by 2-way ANOVA. B) Calculated

Effect of a photoswitchable rotaxane on membrane permeabilization across lipid compositions

• Udyogi N. K. Conthagamage,
• Lilia Lopez,
• Zuliah A. Abdulsalam and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2498–2512, doi:10.3762/bjoc.21.192

• the axle occurs in rotaxane 1, the dominant absorption of the azobenzene units ensures that most of the light energy is directed toward azobenzene photoisomerization. Additionally, their different release kinetics provide more insights: rotaxane 1 causes gradual, stepwise release beginning from the

• sulforhodamine B. Initial studies suggest a photochemical reaction of the axle, which is suppressed when the macrocycle is threaded. Furthermore, the distinct release kinetics and absorption profiles of rotaxane 1 and axle 3, combined with the reversible photoswitching of rotaxane 1 versus the irreversible

Pathway economy in cyclization of 1,n-enynes

• Hezhen Han,
• Wenjie Mao,
• Bin Lin,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173

• control principles for gold catalysis. Temperature-controlled cyclization of 1,n-enynes Temperature, a pivotal thermodynamic parameter, not only governs reaction kinetics but also determines reaction pathways. Typically, kinetic product formation is favored at lower temperatures via pathways with reduced

Thiadiazino-indole, thiadiazino-carbazole and benzothiadiazino-carbazole dioxides: synthesis, physicochemical and early ADME characterization of representatives of new tri-, tetra- and pentacyclic ring systems and their intermediates

• Gyöngyvér Pusztai,
• László Poszávácz,
• Anna Vincze,
• András Marton,
• Ahmed Qasim Abdulhussein,
• Judit Halász,
• András Dancsó,
• Gyula Simig,
• György Tibor Balogh and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169

• Table 3. The preliminary ADME investigation, characterized by first-order kinetics due to low substrate concentration (≤10 µM), aids in establishing intrinsic clearance (Clint), which indicates the predicted elimination efficacy of drugs [43]. According to the generally accepted Clint ≈ 10 μL/min/kg (or

C2 to C6 biobased carbonyl platforms for fine chemistry

• Jingjing Jiang,
• Muhammad Noman Haider Tariq,
• Florence Popowycz,
• Yanlong Gu and
• Yves Queneau

Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165

• wettability (Scheme 11). The group of Gupta et al. investigated the kinetics of the oxidation by tetrachloroaurate(III) in acetic acid–sodium acetate buffer medium of some neutralized α-hydroxy acids, including glycolic acid (GA), lactic acid (LA), α-hydroxybutyric acid (IB), mandelic acid (MA), atrolactic

• kinetics studies, the cross-aldol reaction of formaldehyde and acetaldehyde gives a higher yield of 3-HPO than the self-aldol reaction of acetaldehyde. Moreover, Raney nickel was applied successfully for the conversion of 3-HPO to 1,3-PDO with good yield and about 90% conversion rate of 3-HPO (Scheme 13

• " (FLS), an enzyme able to catalyze the formose process. Various teams investigated the kinetics of the reaction and the entire carbon uptake allowing to select the best computationally modified enzyme profile depending on the formaldehyde amount and guiding future efforts to improve this pathway (Scheme

Solar thermal fuels: azobenzene as a cyclic photon–heat transduction platform

• Jie Yan,
• Shaodong Sun,
• Minghao Wang and
• Si Wu

Beilstein J. Org. Chem. 2025, 21, 2036–2047, doi:10.3762/bjoc.21.159

• , and hinders practical deployment. Third, azobenzene groups release energy through a process involving thermal relaxation or thermally induced cis–trans isomerization. Temperature critically governs the efficiency and kinetics of this process: elevated temperatures accelerate uncontrolled instantaneous

Continuous-flow-enabled intensification in nitration processes: a review of technological developments and practical applications over the past decade

• Feng Zhou,
• Chuansong Duanmu,
• Yanxing Li,
• Jin Li,
• Haiqing Xu,
• Pan Wang and
• Kai Zhu

Beilstein J. Org. Chem. 2025, 21, 1678–1699, doi:10.3762/bjoc.21.132

• continuous-flow nitration technology – a process historically recognized as one of the most hazardous industrial operations – focusing on its technological advancements in process design, reaction kinetics characterization, and practical implementation over the past decade. Detailed discussions encompass

• system configuration strategies, critical process parameters and operating ranges, performance evaluation metrics, universal methodologies for kinetics analysis, safety assessment protocols, and scale-up approaches. The presented content aims to offer actionable guidance for researchers and engineers

• engaged in the development of continuous-flow nitration systems. Keywords: continuous-flow; kinetics; nitration; optimization; scale up; Introduction Nitro compounds hold an extremely important position in the field of organic chemistry, mainly because they are easily obtainable and can be converted

pH-Controlled isomerization kinetics of ortho-disubstituted benzamidines: E/Z isomerism and axial chirality

• Ryota Kimura,
• Satoshi Ichikawa and
• Akira Katsuyama

Beilstein J. Org. Chem. 2025, 21, 1568–1576, doi:10.3762/bjoc.21.120

• barriers by protonation, providing a novel approach to control the kinetics of isomerization via pH adjustment. The results showed that protonation of the amidine moiety significantly suppresses both C–N bond rotation and C–N/C–C concerted rotation, demonstrating the potential of ortho-disubstituted

• salt, the kinetics of the C–N bond rotation at different pH values was then evaluated. The E/Z ratio of the isolated Z-2 trifluoroacetate salt (Z-2-H+) in three buffers (pH 4.6, 5.5, and 6.5, respectively) was calculated by RP-HPLC at different times at 20 °C (Figure 5). The curve fitting analysis of

• peaks corresponding to the atropisomers arising from the C–C axis. Each atropisomer could be separated by chiral HPLC, and the isomer eluting earlier was used for the following kinetic analysis. The effect of pH on the kinetics of the racemization was investigated. The isomer was heated in the buffer

Azobenzene protonation as a tool for temperature sensing

• Antti Siiskonen,
• Sami Vesamäki and
• Arri Priimagi

Beilstein J. Org. Chem. 2025, 21, 1528–1534, doi:10.3762/bjoc.21.115

• they all typically result in significant changes in the absorption spectrum and/or alter the stability of the metastable isomer. In sensing, azobenzenes have been utilized, e.g., through changes in isomerization kinetics [17][18] or colorimetric properties. The colorimetric sensors are effective for

High-pressure activation for the solvent- and catalyst-free syntheses of heterocycles, pharmaceuticals and esters

• Kelsey Plasse,
• Valerie Wright,
• Guoshu Xie,
• R. Bernadett Vlocskó,
• Alexander Lazarev and
• Béla Török

Beilstein J. Org. Chem. 2025, 21, 1374–1387, doi:10.3762/bjoc.21.102

• that could lead to molecular re-alignments during compression and decompression steps that are beneficial for reaction kinetics. Under optimized conditions, the products were isolated with good to excellent yields under a catalyst- and solvent-free environment (Scheme 3). The data in Scheme 3

Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

• of the resulting alkene [36]. In addition, this intramolecular etherification corresponds to the 4-exo-tet cyclisation which, in terms of kinetics, is the least favoured n-exo-tet cyclisation mode where n ≤ 7 [37]. Nevertheless, the Williamson etherification still remains one of the most common

Investigations of amination reactions on an antimalarial 1,2,4-triazolo[4,3-a]pyrazine scaffold

• Henry S. T. Smith,
• Ben Giuliani,
• Kanchana Wijesekera,
• Kah Yean Lum,
• Sandra Duffy,
• Aaron Lock,
• Jonathan M. White,
• Vicky M. Avery and
• Rohan A. Davis

Beilstein J. Org. Chem. 2025, 21, 1126–1134, doi:10.3762/bjoc.21.90

• limited activity against Pf 3D7 resulted in low selectivity indices, as indicated in Table 1. Compounds 3 and 13–15 demonstrated some inhibition of HEK293 at the highest concentrated tested, but did not display sigmoidal dose-dependent kinetics, thus accurate IC50 values were unable to be determined

Recent advances in controllable/divergent synthesis

• Jilei Cao,
• Leiyang Bai and
• Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

• afforded phenanthridinones. Intriguingly, switching to the electron-rich bidentate ligand bis(diphenylphosphino)methane (dppm) redirected the pathway to yield acridones. Time-dependent NMR studies revealed that the selectivity hinges on the aryne release kinetics from its precursor. Employing CsF

• control regioselectivity. It profoundly influences reaction kinetics, stability of intermediates, and reaction equilibria. Through precise temperature modulation, chemists can effectively steer the formation of regioisomers, often achieving desired selectivity with minimal alterations to other reaction

Orthogonal photoswitching of heterobivalent azobenzene glycoclusters: the effect of glycoligand orientation in bacterial adhesion

• Leon M. Friedrich and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2025, 21, 736–748, doi:10.3762/bjoc.21.57

• ][39]. The kinetics of these processes are described by the rate constants k1, k2, k3, and k4, where k1 and k4 describe thermal relaxation of the AB unit and k2 and k3 of the ABF4 unit, respectively. For the thermal Z to E relaxation of the individual glycoazobenzene antennas 6αMan 3, 6βGlc 4, and

• k7 obtained with a first-order exponential decay fit (Table 2 and Supporting Information File 1, Figures S7, S9, and S11). The half-lifes τ1/2 and the activation energies Ea of thermal relaxation were calculated based on the determined rate constants. The kinetics show that thermal relaxation of the

Acyclic cucurbit[n]uril bearing alkyl sulfate ionic groups

• Christian Akakpo,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 717–726, doi:10.3762/bjoc.21.55

•  4b), we observe separate resonances for free Me6PXDA and complexed C1·Me6PXDA which means that the rate of guest exchange is slow on the chemical shift timescale. Slow kinetics of guest exchange is commonly observed for tight host·guest complexes. In contrast, the kinetics of guest exchange are in

Origami with small molecules: exploiting the C–F bond as a conformational tool

• Patrick Ryan,
• Ramsha Iftikhar and
• Luke Hunter

Beilstein J. Org. Chem. 2025, 21, 680–716, doi:10.3762/bjoc.21.54

Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• in P-1 and the molecules pack in a different arrangement, where the double bonds are neither coplanar nor parallel. This product was obtained from propan-2-ol, which may have influenced the crystallization kinetics. The reactive packing mode of Cl2B is enhanced by the hydrogen bonding where the ester

Synthesis of electrophile-tethered preQ₁ analogs for covalent attachment to preQ₁ RNA

• Laurin Flemmich and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35

• reasonably fast labeling kinetics and up to quantitative conversion under quasi-physiological conditions [4]. Obviously, the rapid dissemination and widespread acceptance of such labeling methods depend on fast and simple access to the small molecule probes. Here, we report efficient synthetic routes to

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• oxidize boronic acids such as 47, producing the corresponding alcohols 48 via a single-electron-transfer mechanism that leverages atmospheric oxygen (Scheme 13). While the initial photocatalytic results using NIR-irradiated 46 were promising, the overall reaction kinetics were relatively slow. In response

• heptamethin chain have been proven to be the most effective photocatalysts for accelerating the aza-Henry reaction. The differing reaction kinetics and tests with 9,10-dimethylanthracene suggest that a cooperative mechanism involving both single-electron transfer and singlet oxygen generation via energy

Effect of substitution position of aryl groups on the thermal back reactivity of aza-diarylethene photoswitches and prediction by density functional theory

• Misato Suganuma,
• Daichi Kitagawa,
• Shota Hamatani and
• Seiya Kobatake

Beilstein J. Org. Chem. 2025, 21, 242–252, doi:10.3762/bjoc.21.16

• To quantitatively evaluate the thermal back reaction of compounds N3, N4, and I1–I4, we measured the absorbance decay of the close-ring isomer at various temperatures as shown in Figure 2a,d, and Figure S2 in Supporting Information File 1. The absorbance decay curves obeyed the first-order kinetics

• -hexane at 253 K for N3 and 203 K for I3: open-ring isomer (black line) and under irradiation at 365 nm (yellow line). (c) Photochromic reaction of N4 in n-hexane at room temperature ([N4] = 7.0 × 10−4 M). Absorbance decay curves and first-order kinetics profiles for (a,b) N3 and (d,e) I3 in n-hexane at

Recent advances in electrochemical copper catalysis for modern organic synthesis

• Yemin Kim and
• Won Jun Jang

Beilstein J. Org. Chem. 2025, 21, 155–178, doi:10.3762/bjoc.21.9

• reactions of copper catalysts without ligands face limitations owing to slow electron transfer kinetics, irreversible copper plating, and competing substrate oxidation. To overcome these challenges, Sevov et al. developed a ligand-free, Cu-catalyzed electrochemical Chan–Lam coupling using a ferrocenium salt

Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning

• Pablo Quijano Velasco,
• Kedar Hippalgaonkar and
• Balamurugan Ramalingam

Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3

• consisting of multiple independent parallel reactors. This parallelization enables the collection of high-fidelity data for reaction kinetics and optimization for at least six different chemical reactions. The major bottleneck in HTE synthesis lies in the challenge of isolating and purifying reaction

• of the optimization processes. Liu et al. [69] developed a custom-built Python script to study the kinetics of carbonyldiimidazole-mediated amide formation by analyzing data from online HPLC and in-line FTIR-spectroscopic measurements. Their algorithm was able to automatically detect peaks from

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

• Robin Schulte,
• Dustin Schade,
• Thomas Paululat,
• Till J. B. Zähringer,
• Christoph Kerzig and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

• . From these data, the rate constants of the cycloreversion reactions were generated according to first-order kinetics and used to calculate the enthalpy and entropy of activation with the Eyring equation (Table 1, cf. Supporting Information File 1, equation S5). The analyses revealed half-lives of the

Computational design for enantioselective CO₂ capture: asymmetric frustrated Lewis pairs in epoxide transformations

• Maxime Ferrer,
• Iñigo Iribarren,
• Tim Renningholtz,
• Ibon Alkorta and
• Cristina Trujillo

Beilstein J. Org. Chem. 2024, 20, 2668–2681, doi:10.3762/bjoc.20.224

• free energy correction at double-zeta. The kinetics of some reactions were calculated, applying the transition state theory [40]. Within this theory, the rate constant of an elementary reaction with the free energy barrier ΔG‡ is given by Equation 1, where k is the rate constant in s−1, kB is the

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

• entangle each other. By obtaining images in three dimensions, the orthogonal assembly could be directly visualised throughout the materials microstructure (Figure 2) [17]. This in situ method of CLSM also allows the kinetics of self-assembly to be elucidated, as demonstrated by Wang et al. [23]. By using