Thiazolidinones: novel insights from microwave synthesis, computational studies, and potentially bioactive hybrids

• Luan A. Martinho,
• Victor H. J. G. Praciano,
• Guilherme D. R. Matos,
• Claudia C. Gatto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2025, 21, 2618–2636, doi:10.3762/bjoc.21.203

• compounds 3n and 4n was carried out using torsion angle analysis and 13C NMR chemical shift calculations to evaluate the absence of expected signals in the NMR spectra of these compounds. Their photophysical properties were also assessed, confirming a preference for a fluorescence mechanism via an ICT

• . Photophysical studies indicated a fluorescence mechanism via intramolecular charge transfer (ICT). Results and Discussion Synthesis of 5-arylidene derivatives under microwave heating To find the ideal reaction conditions for the synthesis of 5-arylidene derivatives, benzaldehyde (1a) and rhodanine (2a) were

• decrease in yields (Table 1, entries 19–21). To confirm the critical role of ethylenediamine in the reaction mechanism, an experiment without its presence was conducted, resulting in only 2% of the desired product (Table 1, entry 22). With the optimized reaction conditions established, this methodology was

Visible-light-driven NHC and organophotoredox dual catalysis for the synthesis of carbonyl compounds

• Vasudevan Dhayalan

Beilstein J. Org. Chem. 2025, 21, 2584–2603, doi:10.3762/bjoc.21.200

• Lewis acid-mediated traditional Friedel–Crafts acylation of 2-methoxynaphthalene typically proceeds at the ortho positions relative to the methoxy group due to the electron-rich nature of these sites, while the meta position remains deactivated under the ionic mechanism. Notably, the present work

Total syntheses of highly oxidative Ryania diterpenoids facilitated by innovations in synthetic strategies

• Zhi-Qi Cao,
• Jin-Bao Qiao and
• Yu-Ming Zhao

Beilstein J. Org. Chem. 2025, 21, 2553–2570, doi:10.3762/bjoc.21.198

• . While its mechanism remains incompletely understood, this additive’s unique efficacy in such transformations is unprecedented. Subsequent steps involved hydroxylation of the double bond and the protection of the vicinal diol as a dimethyl ketal giving ester 100. Oxidative dehydrogenation, benzyl

Pentacyclic aromatic heterocycles from Pd-catalyzed annulation of 1,5-diaryl-1,2,3-triazoles

• Kaylen D. Lathrum,
• Emily M. Hanneken,
• Katelyn R. Grzelak and
• James T. Fletcher

Beilstein J. Org. Chem. 2025, 21, 2524–2534, doi:10.3762/bjoc.21.194

• measurably bioactive, including those serving as controls for the five bioactive derivatives, highlighting the additional importance of structural rigidity on bioactivity within this series. Elucidation of the mechanism of action for these bioactive pentacyclic compounds will be the focus of future

• similarity showed significant antimicrobial potency towards Gram-positive bacteria and yeast relative to their non-annulated control analogs as well as to the other annulated pentacycles in this study, warranting a future investigation into their possible mechanism of action. Studies focusing on the

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

• bilayers through the shuttling of the macrocycle carrying the ions or through a relay mechanism [10][11]. In one example, the isomerization of an azobenzene photoswitch incorporated into the axle was used to modulate the shuttling rate of the macrocycle and, consequently, the efficiency of potassium ion

• mechanism of membrane perturbation. Notably, the effect did not appear until after the fourth irradiation cycle. It required multiple light irradiation cycles to trigger a sudden spike in dye release, in contrast to the gradual increase observed with rotaxane 1 from the first cycle onward (Figure 5). Since

• be attributed to the same light-induced phenomenon observed in EYPC/Chol 8:2, which suggests a different mechanism than the disruption caused by azobenzene photoisomerization in rotaxane 1 (Figure 4b and Table 1). Interestingly, membrane rigidity also appears to decrease the effect caused by the

Assembly strategy for thieno[3,2-b]thiophenes via a disulfide intermediate derived from 3-nitrothiophene-2,5-dicarboxylate

• Roman A. Irgashev

Beilstein J. Org. Chem. 2025, 21, 2489–2497, doi:10.3762/bjoc.21.191

• thiophene, promoting further study of these structures and reaction mechanism. 1H NMR spectroscopy of the obtained mixture provided the first key information about its nature, namely the presence of two major products 2 and 3, both of which showed three characteristic singlets with signal integration 1:3:3

• , necessitates consideration of a reaction mechanism beyond straightforward nucleophilic substitution of the nitro group in ester 1. Although the initial reaction probably involves a nucleophilic attack by the S-nucleophile on the activated thiophene ring, resulting in displacement of the nitro group, the

• subsequent fate of the intermediate appears to be critical. Based on our observations and literature data, a probable reaction mechanism was proposed. The initial nucleophilic substitution of the nitro group in ester 1 by the AcS− anion yields the S-acetyl derivative (intermediate A) and NO2− anion. The key

Palladium-catalyzed regioselective C1-selective nitration of carbazoles

• Vikash Kumar,
• Jyothis Dharaniyedath,
• Aiswarya T P,
• Sk Ariyan,
• Chitrothu Venkatesh and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2025, 21, 2479–2488, doi:10.3762/bjoc.21.190

• palladacycle 6 as the catalyst, and the desired nitrated product 2a was obtained in 48% yield (Scheme 5c). This result supports the involvement of palladacycle intermediate 6 in the catalytic cycle. Proposed mechanism Based on our experimental results and related literature precedents [68][69][74][75][76][77

The intramolecular stabilizing effects of O-benzoyl substituents as a driving force of the acid-promoted pyranoside-into-furanoside rearrangement

• Alexey G. Gerbst,
• Sofya P. Nikogosova,
• Darya A. Rastrepaeva,
• Dmitry A. Argunov,
• Vadim B. Krylov and
• Nikolay E. Nifantiev

Beilstein J. Org. Chem. 2025, 21, 2456–2464, doi:10.3762/bjoc.21.187

• furanose form through steric and electrostatic effects. In our previous work [24], we investigated the energetic aspects of the pyranoside-into-furanoside (PIF) rearrangement that proceeded under acid-promoted sulfation and whose mechanism was studied by us previously [25] along with the mechanism of

Catalytic enantioselective synthesis of selenium-containing atropisomers via C–Se bond formations

• Qi-Sen Gao,
• Zheng-Wei Wei and
• Zhi-Min Chen

Beilstein J. Org. Chem. 2025, 21, 2447–2455, doi:10.3762/bjoc.21.186

• formation proceeded through an SN2-type nucleophilic substitution mechanism (Scheme 1). In 2025, Li and co-workers reported a highly efficient rhodium-catalyzed enantioselective C–H selenylation reaction of 1-arylisoquinolines with diselenides, employing 3,5-(CF3)2C6H3CO₂Ag and AgSbF6 as additives [19

• reaction yielded the desired product at room temperature with high regioselectivity and stereoselectivity (E/Z ratio >99:1). Notably, when chiral catalyst (cat.1) was used, the reaction afforded the axially chiral product 9 in 43% yield with 84% ee. The proposed mechanism proceeds as follows. Catalyst cat

• alkyne insertion step may be rate-limiting, as it involves the participation of selenol, alkyne, and the rhodium catalyst. The Rh(III) mechanism appears to be more plausible than route B, which can be attributed to the enhanced ion-pairing effect resulting from the higher oxidation state of rhodium

Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds

• Natalya Akhmetdinova,
• Ilgiz Biktagirov and
• Liliya Kh. Faizullina

Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185

• via the oxo-nitrile mechanism, with formation of the corresponding Α-pentacyclic 3-ethyl α,β-alkenenitriles 49 and 50 with yields of 44% to 45% (Scheme 9). Cytotoxic screening was performed using the MTT assay with a panel of 7 human tumor cell lines, and showed that the synthesized triterpenoids 47

• aldehyde 53 [39] (Scheme 10). The key steps in this synthesis are based on an asymmetric rhodium-catalyzed [4 + 2] cycloaddition reaction [40], followed by a unique benzilic acid-type rearrangement under very mild conditions [41]. A step-by-step mechanism for the benzilic acid-type rearrangement of

• reported a stereospecific reduction of an acyloin ring controlled by the chirality of a glucose fragment at position C5, and suggested a possible mechanism for hydrogen migration during the conversion of C5 (sp2) to C5 (sp3). The key 3,4,6-trihydroxycyclohexadienone 76 was obtained by a sequence of Friedel

The high potential of methyl laurate as a recyclable competitor to conventional toxic solvents in [3 + 2] cycloaddition reactions

• Ayhan Yıldırım and
• Mustafa Göker

Beilstein J. Org. Chem. 2025, 21, 2389–2415, doi:10.3762/bjoc.21.184

• the cycloaddition reaction in a non-polar solvent, such as methyl laurate, indicates that it proceeds via a non-polar mechanism. The lower polarity of the activated complex in comparison to the starting compounds supports the higher reaction rate in an non-polar solvent such as methyl laurate [61][106

An Fe(II)-catalyzed synthesis of spiro[indoline-3,2'-pyrrolidine] derivatives

• Elizaveta V. Gradova,
• Nikita A. Ozhegov,
• Roman O. Shcherbakov,
• Alexander G. Tkachenko,
• Larisa Y. Nesterova,
• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2025, 21, 2383–2388, doi:10.3762/bjoc.21.183

• . Third, the introduction of an ortho-methyl substituent on the ketone moiety (3m) likewise suppressed product formation, likely due to steric hindrance interfering with cyclization at the C3 position of the indole ring. Based on literature precedents [15][16], we propose a mechanism involving a radical

• mmol scale experiment. The scope of the Fe-catalyzed spirocyclization. aIsolated yield of the 4.2 mmol scale experiment. The proposed mechanism of product 4 formation. Supporting Information Supporting Information File 2: General reaction procedures, compound characterization data, and copies of NMR

Conformational effects on iodide binding: a comparative study of flexible and rigid carbazole macrocyclic analogs

• Guang-Wei Zhang,
• Yong Zhang,
• Le Shi,
• Chuang Gao,
• Hong-Yu Li and
• Lei Xue

Beilstein J. Org. Chem. 2025, 21, 2369–2375, doi:10.3762/bjoc.21.181

• work represents one of the earliest comparative studies on the anion-binding behaviors of carbazole-based structural analogs, demonstrating that a flexible macrocycle markedly improves iodide binding affinity via an induced-fit mechanism. The flexible analog PBG exhibits a 22.78-fold higher

• demonstrated that flexible PBG achieves superior I− binding (KPBG = 1.387 × 105 M−1) through induced-fit conformational adjustments, whereas rigid WDG (KWDG = 6.089 × 103 M−1) is constrained by preorganized cavity geometry, adhering to a conformational selection mechanism. This work elucidates the synergistic

• spectroscopy and fluorescence spectroscopy, combined with Benesi–Hildebrand equation [23] and nonlinear curve fitting [24]. The purpose of systematically exploring the difference between the two types of recognition of I− is to reveal the regulation law of conformational dynamics on the binding mechanism

Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications

• Jullyane Emi Matsushima,
• Khushbu,
• Zuliah Abdulsalam,
• Udyogi Navodya Kulathilaka Conthagamage and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179

• CC BY 4.0. (a) Structure of the [2]rotaxane and (b) mechanism for K+ cations transport across lipid bilayers. Figure 6 was adapted from [51], C. Wang et al., “A Light-Operated Molecular Cable Car for Gated Ion Transport”, Angew. Chem., with permission from John Wiley and Sons. Copyright © 2021 Wiley

Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis

• Peng-Xi Luo,
• Jin-Xuan Yang,
• Shao-Min Fu and
• Bo Liu

Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177

• ][2][3]. These studies revealed distinct reaction types, with the Norrish type II reaction being one of the most extensively characterized. The mechanism underlying the Norrish type II reaction proceeds via the following steps (Scheme 1a): photoexcitation of carbonyl compound A generates an excited

• pyrrolidine-derived phenyl keto amide substrate 91 with blue LEDs produces the pyrrolidine-fused 4-oxazolidinone (N,O-acetal) 92, precluding preparation of the pyrrolidine analog of lycoplatyrine A (94) by this method. Compound 92 is presumably formed via either the radical mechanism [41] or possibly

• stereoretentive photoredox reaction of naphthoquinones initiated by Norrish type-II hydrogen abstraction [45][46][47][48][49][50][51]. The mechanism involves three consecutive photoinduced events: (1) hydrogen abstraction by the excited quinone to generate a biradical species; (2) intramolecular SET process

Insoluble methylene-bridged glycoluril dimers as sequestrants for dyes

• Suvenika Perera,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 2302–2314, doi:10.3762/bjoc.21.176

• , graphene functionalized with β-cyclodextrins [18], a starch-based β-cyclodextrin polymer [19], and pillar[5]arene-based crosslinked polymers have also been investigated as sequestrants for dyes [20]. The Isaacs group has a longstanding interest in the synthesis and mechanism of formation of macrocyclic

Enantioselective radical chemistry: a bright future ahead

• Anna C. Renner,
• Sagar S. Thorat,
• Hariharaputhiran Subramanian and
• Mukund P. Sibi

Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174

• one way to convert a free radical to a more stable intermediate, which can subsequently undergo coupling with another radical via an SH2 (bimolecular homolytic substitution) mechanism. Lastly, some noteworthy radical processes proceed through a radical–polar crossover pathway, in which one-electron

• oxidation or reduction of the radical yields a cationic or anionic intermediate that participates in a subsequent step through a polar mechanism. An important aspect of many of these radical reactions is that they can result in the formation of new carbon–carbon bonds, a fundamental goal in organic

• mechanism involving single-electron oxidation of an enamine intermediate, addition of the resulting radical to the olefin, single-electron oxidation of the adduct to form a carbocationic intermediate, and intramolecular nucleophilic attack on the carbocation to form the pyrrolidine ring. The reaction

Pd-catalyzed dehydrogenative arylation of arylhydrazines to access non-symmetric azobenzenes, including tetra-ortho derivatives

• Loris Geminiani,
• Kathrin Junge,
• Matthias Beller and
• Jean-François Soulé

Beilstein J. Org. Chem. 2025, 21, 2234–2242, doi:10.3762/bjoc.21.170

• . Finally, di-ortho-substituted azobenzene 5d was also successfully prepared using this approach, achieving an excellent yield of 80%. The mechanism of the reaction was further outlined to explain the formation of all identified main and side-products (Figure 2). A two-step cascade Pd-catalyzed reaction is

• ) undergoes dehydrogenation via a mechanism involving Pd and O2, similar to the process reported by Huang and co-workers [59]. Initially, Pd(0) species E is oxidized to Pd(II) by O2, forming a Pd-peroxo complex F [60]. Subsequently, ligand exchange occurs between the deprotonated N,N-diarylhydrazine and

Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings

• Lifen Peng,
• Ting Wang,
• Zhiwen Yuan,
• Bin Li,
• Zilong Tang,
• Xirong Liu,
• Hui Li,
• Guofang Jiang,
• Chunling Zeng,
• Henry N. C. Wong and
• Xiao-Shui Peng

Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166

• in 66%–87% yields. Boc-amino ester (2e), dipeptide (2f), apivalate ester (2g) and ethinyl estradiol (2h) skeletons were also tolerated well. According to the previous works [163] and the experimental results, the authors proposed a plausible mechanism. Firstly, the anodic oxidation of [Cp2Fe

• in 89% and 63% yield, respectively. Based on the results of control experiments and the previous reports [186], a plausible reaction mechanism was deduced. Firstly, treatment of [RuCl2(p-cymene)]2 with NaOAc afforded the ruthenium diacetate species A, which underwent complexation with 4 and

• ][194][195][196][197][198][199][200], the authors proposed a possible reaction mechanism. For the synthesis of 11a in Pt plate electrodes, two-electron anodic oxidation of I− formed I+. Addition of I+ to C≡C in 10 resulted in the production of A. Meanwhile, continuous reduction of H2O at the cathode

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

• ) [71]. The Bobleter and Feather groups investigated the reaction mechanism of the conversion of these C3 compounds. The acid-catalyzed equilibrium between 1,3-dihydroxy-2-propane and 2,3-dihydroxypropanal involves an ene-triol intermediate which leads to methylglyoxal by a dehydration reaction at

• catalysis. The mechanism first involves the isomerization of xylose into xylulose under Lewis acid-type catalysis, and the subsequent dehydration of xylulose into furfural under Brønsted acid-type catalysis (Scheme 47). Humins are naturally formed in all processes involving the acid-catalyzed degradation of

• isomerization and hydrogenation (Scheme 70, route b2). The accepted mechanism of the rehydration of HMF under acidic conditions leading to the formation of levulinic acid and formic acid proposed by Horvat [224] is depicted in Scheme 71. Levulinic acid can be converted into various derivatives, such as esters

Discovery of cytotoxic indolo[1,2-c]quinazoline derivatives through scaffold-based design

• Daniil V. Khabarov,
• Valeria A. Litvinova,
• Lyubov G. Dezhenkova,
• Dmitry N. Kaluzhny,
• Alexander S. Tikhomirov and
• Andrey E. Shchekotikhin

Beilstein J. Org. Chem. 2025, 21, 2062–2071, doi:10.3762/bjoc.21.161

• tumor cells may proceed via an alternative, DNA-independent mechanism. Conclusion In this study, a diverse set of indolo[1,2-c]quinazoline derivatives was synthesized through functionalization at positions 5, 6, and 12 of the polyannelated scaffold. The work highlights the synthetic versatility of the

• development. Further investigations are warranted to elucidate their precise mechanism of action and optimize their therapeutic profile. Structure of indolo[1,2-c]quinazoline, its selected derivatives, and related structures with biological activity. Fluorescence quenching of compounds 7a–c (2 μM) upon

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

• ]. Since Olmsted’s pioneering exploration of azobenzene compounds as solar thermal fuels in 1983 [42], significant breakthroughs have been achieved through interdisciplinary integration of organic synthesis, functional materials engineering, photophysical mechanism analysis, and computational chemistry. So

• and Visible Light Storage”, Adv. Energy Mater., with permission from John Wiley and Sons. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. This content is not subject to CC BY 4.0. (c) Schematic of the mechanism for photothermal energy and phase change energy storage of azopyridine

Understanding the origin of stereoselectivity in the photochemical denitrogenation of 2,3-diazabicyclo[2.2.1]heptene and its derivatives with non-adiabatic molecular dynamics

• Leticia A. Gomes and
• Steven A. Lopez

Beilstein J. Org. Chem. 2025, 21, 2007–2020, doi:10.3762/bjoc.21.156

• synthetic organic chemists. We report a computational study on the mechanism of diazabicyclo[2.2.1]heptenes to address long standing mechanistic questions. Indeed, the mechanism of these reactions has been disputed for over six decades. We employed non-adiabatic molecular dynamics (NAMD) simulations

• preference for inversion across several derivatives of 1 [77][78]. These studies suggest that the thermal denitrogenation of diazabicyclo[2.1.1]hep-2-ene undergoes a concerted mechanism of elimination of nitrogen, while the photochemical reaction proceeds via a stepwise mechanism. Quantum mechanical

• the denitrogenation mechanism of 7,7‐diethoxy‐2,3‐diazabicyclo[2.2.1]hept‐2‐ene, showing that a stepwise C–N-bond cleavage is energetically favored using broken‐symmetry (BS)‐(U)CCSD/6‐31G(d) and suggested that an equatorial conformation of the diazinyl diradical leads to the formation of the inverted

Measuring the stereogenic remoteness in non-central chirality: a stereocontrol connectivity index for asymmetric reactions

• Ivan Keng Wee On,
• Yu Kun Choo,
• Sambhav Baid and
• Ye Zhu

Beilstein J. Org. Chem. 2025, 21, 1995–2006, doi:10.3762/bjoc.21.155

• above (Figure 1). These transformations scattered across a broad area: 10 showed 20 × i > N >10 × i, and 9 showed 10 × i > N > 5 × i. Although neither Nnon-H of the catalyst nor the index [ij] is related to the mechanism of stereocontrol, a low N-to-i ratio could occur when attractive secondary

Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis

• Rasma Kroņkalne,
• Rūdolfs Beļaunieks,
• Armands Sebris,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2025, 21, 1984–1994, doi:10.3762/bjoc.21.154

• chemoselectivity towards diene formation (Table 1, entries 15 and 16). In accordance with the proposed reaction mechanism (Scheme 2), an equimolar amount of protons is generated in the reaction, which would likely induce the formation of additional side-products either by protodecupration [27] or the acid

• -butyldimethylsilyl)hex-5-yn-1-yl)-N-phenylaniline (15). Thus, acylamides were found to have optimal pKa and nucleophilicity to react according to our desired pathway (Scheme 4). For the heterocyclization mechanism under arylating conditions, we propose a Cu(I/III) catalyzed pathway (Scheme 5). Firstly, the copper(I

• mmol/mL; c) 1.2 equiv I-1, [CuOTf]2·PhH (2.5 mol %), 70 °C, 22 h, c7g = 0.1 mmol/mL; d) 1.2 equiv I-1, [CuOTf]2·PhH (2.5 mol %), 70 °C, 3 h, c7h = 0.1 mmol/mL. Proposed arylation–heterocyclization mechanism for internal nucleophile-containing silanes 7. Arylation of C5-chain containing acylamides 16a–c