Get a better glimpse on sequential photoreactions of trisnorbornadienes with ¹⁹F NMR spectroscopy

• Julian Felix Maria Hebborn,
• Ben Eric Merten,
• Thomas Paululat and
• Heiko Ihmels

Beilstein J. Org. Chem. 2026, 22, 527–534, doi:10.3762/bjoc.22.38

• storage. The target compound was readily synthesized by a Suzuki–Miyaura coupling reaction and examined with respect to the key properties for MOST applications. Upon direct or photosensitized irradiation, the trisnorbornadiene was transformed stepwise and almost quantitatively into the corresponding

• thermal energy storage; photochemistry; photochromism; quadricyclanes; Introduction Photochromic compounds, which change their physical and chemical properties reversibly upon irradiation, figure as a versatile basis for the development of functional materials, whose performance can be switched or

• emerging approach towards molecular solar thermal (MOST) energy storage [5][6][7][8]. In this context, norbornadienes are employed as well established photoswitches because they provide several favorable photochemical and physicochemical properties [9][10]. In a photochromic intramolecular [2 + 2

Synthesis and uranyl(VI) extraction performance of a calix[4]pyrrole–tetrahydroxamic acid receptor

• Sara Karnib,
• Rana Baydoun,
• Wissam Zaidan,
• Nancy AlHaddad,
• Omar El Samad,
• Bilal Nsouli,
• Francine Cazier-Dennin and
• Pierre-Edouard Danjou

Beilstein J. Org. Chem. 2026, 22, 486–494, doi:10.3762/bjoc.22.36

• , industrial and biological applications [5][6][7][8]. Among these macrocycles, calix[4]pyrroles (CPs) represent a modern generation of supramolecular materials with interesting chelation properties [9]. These nonplanar, non-aromatic, tetrapyrrolic macrocycles consist of four pyrrolic units linked together at

• leaching into water was confirmed by depositing a drop of the aqueous supernatant on a TLC plate, which showed no formation of the characteristic red iron-hydroxamate complex upon treatment with FeCl3. These physicochemical properties precluded standard liquid–liquid extraction but were suitable for a

• these, 238U is by far the most abundant, accounting for 99.28 % by mass, followed by 235U (0.72 %) and 234U (0.0058 %). Although these isotopes possess identical chemical properties, they differ in their radioactive characteristics [59]. Since the extraction experiments depend on the chemical behavior

Synthesis of a HDAC inhibitor–nanogold probe for cryo-EM visualization in class I HDAC co-repressor complexes

• Wiktoria A. Pytel,
• John W. R. Schwabe and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2026, 22, 480–485, doi:10.3762/bjoc.22.35

• independently and that their activities and modulation by inhibitors and activators are closely coupled. Both enzymes exist in at least two distinguishable states that differ in their kinetic properties, consistent with the two distinct structural states of the complex observed in the cryo-EM maps [10]. However

Recent advances in the stereoselective synthesis of distal biaxially chiral molecules

• Fanxing Zhou,
• Chen Zhang,
• Lingyu Sun,
• Yiyun Fang,
• Siming Zheng,
• Lina Hu,
• Mengyang Shen,
• Zhen Zhao,
• Wei Xu,
• Yunqiang Sun and
• Zi-Qiang Rong

Beilstein J. Org. Chem. 2026, 22, 461–479, doi:10.3762/bjoc.22.34

• , investigation of the photophysical properties revealed that the enantiomers exhibited promising features for chiral functional materials, including circularly polarized luminescence (CPL). More recently, Tu’s group described a cobalt-catalyzed direct oxidative coupling of phenols, enabling the synthesis of

Structural reassignment of compound 968, an allosteric glutaminase inhibitor

• Lindsey A. Albertelli,
• Sainabou Jallow,
• Chun Li and
• Scott M. Ulrich

Beilstein J. Org. Chem. 2026, 22, 455–460, doi:10.3762/bjoc.22.33

• were published or without knowledge of these results. The structure reassignment of compound 968 should aid in medicinal chemistry efforts around this scaffold with increased potency and improved pharmacological properties. Experimental General X-ray data were obtained on a Bruker Smart Breeze CCD

A facile and practical method for the synthesis of trans-(±)-taxifolin and its derivatives via Darzens reaction

• Bo Peng,
• Panpan Yang,
• Maaz Khan,
• Xiaotong Lin,
• Jiang Wu,
• Peng Fu and
• Qingqing Wu

Beilstein J. Org. Chem. 2026, 22, 443–450, doi:10.3762/bjoc.22.31

• experiments have demonstrated that taxifolin has unexpected pharmacological properties [2][3][4] such as antioxidant, anti-inflammatory, anti-apoptosis and neuroprotective effects. Thus, taxifolin exhibits great potential in the treatment of a series of diseases [3][4][5] involving organ or tissue injury

• properties. As the key precursor to enantiomerically pure trans-(+)-taxifolin and its derivatives, the development of an economical and practical synthetic route towards racemic trans-(±)-taxifolin or its derivatives has consistently attracted the attention of chemists. Currently, the most prevalent

Synthesis and stereochemical analysis of dynamic planar chiral oxa[7]orthocyclophene

• Yukiho Hashimoto,
• Yuuya Kawasaki,
• Kazunobu Igawa and
• Katsuhiko Tomooka

Beilstein J. Org. Chem. 2026, 22, 436–442, doi:10.3762/bjoc.22.30

• procedures, characterization data, copies of 1H and 13C NMR spectra, and optimized geometries of DFT calculations. Supporting Information File 26: Crystallographic information file of compound 1ac. Acknowledgements We thank K. Imamura (Evaluation center of material properties, IMCE Kyushu University) for

Synthesis and anti-cancer activity of naphthalimide–organylselanyl conjugates

• Rajkumar Ravi and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2026, 22, 416–435, doi:10.3762/bjoc.22.29

• analyses, and structure and electronic properties were further investigated using density functional theory (DFT) calculations. Cytotoxicity tests were used to assess the anticancer potential of both conjugates, and it was found that both compounds showed notable activity against the test MDA-MB-231 breast

• characteristics and electronic properties of compounds 7 and 8, geometry optimisations and frequency calculations were performed using density functional theory (DFT) with the B3LYP functional and the 6-31G(d,p) basis set, as shown in Figure 3 [56][57]. The input structure of compound 7 was obtained from a single

• cytotoxicity test, molecular docking studies were carried out to obtain a deeper understanding of the behaviour of compounds 7 and 8. It is crucial to understand that these compounds' molecular structure, which establishes important properties like molecular flexibility and their capacity to form different non

Design, synthesis and biological evaluation of 2,5-diaryloxazolo[4,5-d]pyrimidin-7-ylamines as selective cytotoxic agents against HeLa cells

• Maryna V. Kachaeva,
• Agnieszka B. Olejniczak,
• Marta Denel-Bobrowska,
• Victor V. Zhirnov,
• Yevheniia S. Velihina,
• Stepan G. Pilyo and
• Volodymyr S. Brovarets

Beilstein J. Org. Chem. 2026, 22, 390–398, doi:10.3762/bjoc.22.27

• Cytotoxic properties of the studied compounds were assessed on the non-cancer cell line NCTC clone 929 (Mus musculus normal subcutaneous connective tissue cells), as well as four human cancer cell lines: HeLa (Human cervix adenocarcinoma cells), A549 (Human lung carcinoma cells), HepG2 (Human hepatocellular

• of drug candidate development, taking into account the expected pharmacokinetic and toxicological, as well as undesirable properties of the molecules. At the same time, drug similarity filters developed by pharmaceutical companies based on the physicochemical properties of approved drugs with known

• mechanisms of action have utilitarian value, as they do not account for the probability of including targets not inherent to existing drugs in their molecular mechanisms of anticancer action. The physicochemical properties of such compounds may not fit the parameters developed from databases of approved

Dialkylaminoalkylation of β-ketosulfones via ring-opening of 3-sulfonylpyrrolidines

• Evgeny M. Buev,
• Alexander V. Pavlushin,
• Vladimir S. Moshkin and
• Vyacheslav Y. Sosnovskikh

Beilstein J. Org. Chem. 2026, 22, 383–389, doi:10.3762/bjoc.22.26

• effects [14], сoagulation enzyme factor (FXa) inhibition [15] and antidepressant properties [16]. Considering the approaches to the synthesis of γ-aminosulfones, we focused our attention on the implementation of an aminoalkylation as a powerful and versatile tool for the synthesis of aliphatic amines [17

Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• comparatively underdeveloped [30], despite the appealing prospect of higher barriers to enantiomerization and richer optoelectronic behavior [31]. In 2021, Yorimitsu and co-workers disclosed a series of symmetric dihetero[8]helicenes I–IV that exhibited intriguing chiroptical properties utilizing the

• shortest route reported to any unsymmetrical hetero[8]helicene. We then investigated the structural, photophysical and chiroptical properties of these new oxaza[8]helicenes and benchmarked their behavior against their corresponding oxaza[7]helicene analogues. Results and Discussion Electrosynthesis of

• . Structural properties of oxaza[8]helicenes Aromaticity We evaluated the aromaticity of the oxaza[8]helicenes 5a and 5b using nucleus-independent chemical shifts (NICS), as proposed by Schleyer and co-workers [57][58]. As shown in Figure 2A, the terminal rings exhibit higher aromatic character and a

Non-central chirality in organic chemistry

• Ken Tanaka and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2026, 22, 370–371, doi:10.3762/bjoc.22.24

• ; chiroptical properties; molecular chirality; Chirality is a foundational concept in organic chemistry, traditionally framed around tetrahedral carbon stereocenters. Over the past decades, however, it has become increasingly clear that molecular handedness is not confined to localized points in space. Axes

• functional properties associated with axially, helically, planarly, or inherently chiral molecules underscore their growing relevance in materials-oriented research. Beyond these functional roles, some contributions highlight an even more fundamental aspect of non-central chirality: in certain cases, the

Synthesis of tricyclic fused pyrrolidine nitroxides from 2-alkynylpyrrolidine-1-oxyls

• Mark M. Gulman,
• Yuliya F. Polienko,
• Sofia Yu. Trakhininа,
• Yuri V. Gatilov,
• Tatyana V. Rybalova,
• Sergey A. Dobrynin and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2026, 22, 344–351, doi:10.3762/bjoc.22.22

• framework is impossible is one of the ways to improve properties of ORCA. Feasibility of the synthesis of rigid 3b,4,5,6,6a,7-hexahydropyrrolo[2',3':3,4]pyrrolo[1,2-c][1,2,3]triazole and 3b,4,5,6,6a,7-hexahydropyrrolo[2',3':3,4]pyrrolo[1,2-b]pyrazole ring systems with incorporated nitroxide moiety from 2

• nitroxides are incorporated into macromolecular or nanosized supramolecular structures, which modulate nitroxide properties. For example, the efficiency of ORCA (relaxivity) directly depends on the rotational correlation time of the radicals attached to the scaffold [13][14][15]. Large structures in which

Ring contraction and ring expansion reactions in terpenoid biosynthesis and their application to total synthesis

• Nicolas Kratena,
• Nicolas Heinzig and
• Peter Gärtner

Beilstein J. Org. Chem. 2026, 22, 289–343, doi:10.3762/bjoc.22.21

• these puzzling questions or even result in reassignment of the molecular structure [6][7][8][9][10]. Nevertheless, terpenoids with novel or highly uncommon carbon skeleta continue to attract interest from both biologists and chemists, as they often possess interesting biological properties owing to

Spirobarbiturates with a pyrrolizidine moiety: synthesis, structure and biological evaluation

• Arthur A. Puzyrkov,
• Andrew S. Drachuk,
• Ekaterina A. Popova,
• Alexander V. Stepakov and
• Vitali M. Boitsov

Beilstein J. Org. Chem. 2026, 22, 274–288, doi:10.3762/bjoc.22.20

• =O···H ≈ 3.6 Å, which is consistent with weak hydrogen-bonding interactions. In silico analyses of drug-like properties. An in silico analysis was performed to preliminarily determine whether the synthesized spiro-fused adducts have drug-like properties. The physicochemical profile was determined

• properties: absorption, distribution, metabolism, excretion, and toxicity. In this paper, these were evaluated in silico using an online resource accessible via https://preadmet.webservice.bmdrc.org/. The following ADME descriptors were selected: blood-brain barrier permeability (BBB), human intestinal

Arene activation via π-bond localization: concepts and opportunities

• Paul Meiners,
• Julian J. Melder and
• Tobias Morack

Beilstein J. Org. Chem. 2026, 22, 257–273, doi:10.3762/bjoc.22.19

• transformations for the synthesis of complex, three-dimensional molecular architectures with tailored physicochemical properties. Despite notable advances in dearomative methodologies over the past decades, the selective and controlled disruption of the aromatic core continues to represent a fundamental challenge

• behavior of aromatic compounds, finally establishing the concept of aromaticity. This behavior manifests itself in numerous illustrative criteria, such as bond-length equalization, enhanced stability, and distinct magnetic and spectroscopic properties, none of which are entirely free of ambiguity [3

• dimension of control: chirality at the metal center. The resulting enantioenriched complexes have enabled a suite of asymmetric transformations (vide infra) [47]. Structure and properties To rationalize and predict the enhanced reactivity of η2-bound arenes, it is instructive to first examine the properties

A mild and atom-efficient four-component cascade strategy for the construction of biologically relevant 4-hydroxyquinolin-2(1H)-one derivatives

• Dmitrii A. Grishin,
• Kseniia I. Sharkovskaia,
• Ilya G. Kolmakov,
• Daria A. Ipatova,
• Rostislav A. Petrov,
• Nikolai D. Dagaev,
• Dmitry A. Skvortsov,
• Maria G. Khrenova,
• Valeriy V. Andreychev,
• Sergei A. Evteev,
• Yan A. Ivanenkov,
• Roman L. Antipin,
• Olga А. Dontsova and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2026, 22, 244–256, doi:10.3762/bjoc.22.18

• ][31][32]. Notably, many derivatives display pronounced antimicrobial properties, with several members of this class exhibiting inhibitory activity against Mycobacterium tuberculosis, thus representing potential candidates for antituberculosis therapy [33]. Their efficacy has also been demonstrated

• -hydroxyquinoline core – 3-(6-halo-4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)-3-(3,4-dimethoxyphenyl)propanoates (Figure 2). The C6 position of the quinoline ring was halogenated with fluorine, chlorine, or bromine, as halogenation at this site is known to influence both the physicochemical properties and biological

• our preliminary findings, we report an efficient four-component strategy for the synthesis of previously inaccessible 4-hydroxyquinoline-2(1H)-one derivatives of the type shown in Figure 2, together with an initial evaluation of their antibacterial and cytotoxic properties. This strategy delivers

Configuration–packing synergy enabling integrated crystalline-state RTP and amorphous-state TADF

• Ruiyan Wang and
• Yunan Wu

Beilstein J. Org. Chem. 2026, 22, 224–236, doi:10.3762/bjoc.22.16

• influencing the electronic properties and excited-state dynamics of 1. Building on the crystallographic data, quantum-chemical calculations were performed using the Gaussian 09 software at the B3LYP level of theory. The calculations revealed that the highest occupied molecular orbital (HOMO) is primarily

• exhibit TADF, which is a process where delayed fluorescence is observed due to thermal activation. Alternatively, the material may also exhibit RTP, depending on the environmental conditions and the specific molecular interactions. These findings highlight the promising photophysical properties of 1

• and RTP. This result provides valuable insights into the excited-state dynamics of 1 and its potential for optoelectronic applications. In order to fully characterize the solid-state emission properties of 1, a comprehensive set of measurements was performed, including steady-state and post-excitation

Synthesis of diaryl phosphates using phytic acid as a phosphorus source

• Kazuya Asao,
• Seika Matsumoto,
• Haruka Mori,
• Riku Yoshimura,
• Takeshi Sasaki,
• Naoya Hirata,
• Yasuyuki Hayakawa and
• Shin-ichi Kawaguchi

Beilstein J. Org. Chem. 2026, 22, 213–223, doi:10.3762/bjoc.22.15

• phosphorus source [15]. There are three types of phosphate esters – monoesters, diesters, and triesters – which differ in their physical properties, reactivities, and practical applications (Figure 1). Phosphate monoesters and diesters are commonly found in biomolecules such as nucleobases and adenosine

Streptoquinolines A and B, new antibacterial meroterpenoids produced by Streptomyces sp. TMPU-A0679

• Akiho Yagi,
• Hitomi Tomura,
• Ami Konno and
• Ryuji Uchida

Beilstein J. Org. Chem. 2026, 22, 185–191, doi:10.3762/bjoc.22.12

• preparative HPLC, yielding streptoquinolines A (1, 7.50 mg) and B (2, 8.05 mg). The physicochemical properties of 1 and 2 are summarized in Table 1. Compounds 1 and 2 showed characteristic absorption maxima at 200–202, 214, 231–234, 312, and 349–350 nm in UV spectra. Common IR absorption bands at 3414–3427

• undertaking the total synthesis of this putative natural precursor to further confirm its structure and biological properties. To date, only two structurally related meroterpenoids to 1 and 2 have been reported: thallusin [7] and saccharoquinoline [8], both of which share a drimane-type sesquiterpene skeleton

• ) and B (2). Structural elucidation of compounds 1 and 2 by 2D NMR experiments. ROESY correlations of 1. Physicochemical properties of 1 and 2. 1H and 13C NMR chemical shifts in 1 and 2.a MICs of 1 and 2. Supporting Information Supporting Information File 12: MS and NMR spectra of streptoquinolines A

Improved synthesis and physicochemical characterization of the selective serotonin 2A receptor agonist 25CN-NBOH

• Adrian G. Rossebø,
• Hannah G. Kolberg,
• Anders E. Tønder,
• Louise Kjaerulff,
• Poul Erik Hansen,
• Karla A. Frydenvang,
• Jesper Østergaard and
• Jesper L. Kristensen

Beilstein J. Org. Chem. 2026, 22, 175–184, doi:10.3762/bjoc.22.11

• characterization of 25CN-NBOH and report key physicochemical properties in the solid state as well as in the solution state, namely stability, ionization, solubility, partition coefficient, and membrane permeability. We show that the hydrochloride salt is a stable and well-defined crystalline compound that is also

• respect to the physiochemical properties and handling of the compound in various research scenarios. Keywords: intramolecular hydrogen bond; membrane permeability; solubility; stability; synthesis; Introduction In recent years, classical psychedelics such as psilocybin and LSD have re-emerged as

• selective 5-HT2AR activation in vitro and in vivo [6]. A review published in 2021 provide an in-depth introduction to the pharmacological properties and various applications [7]. More recent examples include the mapping of the cortical correlates of the so-called head-twitch response in mice [8

A new synthesis of Tyrian purple (6,6’-dibromoindigo) and its corresponding sulfonate salts

• Holly Helmers,
• Mark Horton,
• Julie Concepcion,
• Jeffrey Bjorklund and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2026, 22, 167–174, doi:10.3762/bjoc.22.10

• ][17]. In this work, we describe a more direct, chromium-free synthesis of 1 using inexpensive p-bromotoluene (5), as a starting material, which is also suitable for obtaining similar analogs. Moreover, we describe the sulfonation of 1, which yields a water-soluble dye similar in properties to indigo

Asymmetric Mannich reaction of aromatic imines with malonates in the presence of multifunctional catalysts

• Kadri Kriis,
• Harry Martõnov,
• Annette Miller,
• Mia Peterson,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2026, 22, 151–157, doi:10.3762/bjoc.22.8

• product in a slightly less enantioselective way (71% ee). When comparing the halogen bond donor properties of tetrafluoroiodophenyl and iodophenyl moieties, the latter is weaker as it is less electron-withdrawing. However, there is a very small difference between reactivity and selectivity for catalysts E

Design and synthesis of an axially chiral platinum(II) complex and its CPL properties in PMMA matrix

• Daiki Tauchi,
• Sota Ogura,
• Misa Sakura,
• Kazunori Tsubaki and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2026, 22, 143–150, doi:10.3762/bjoc.22.7

• two platinum(II) chromophore units, leading to the chiroptical properties in the MLCT region through exciton coupling under restricted molecular motion. Keywords: axial chirality; chiral chemistry; circularly polarized luminescence (CPL); phosphorescence; platinum(II) complex; Introduction

• , pincer-type platinum(II) complexes have attracted particular attention, owing to the structural robustness imparted by tridentate chelating ligands and their excellent luminescent properties [12][13][14][15][16][17]. These complexes have been widely investigated, not only for practical application but

• also from the perspective of fundamental chemistry. In recent years, the design and synthesis of luminescent pincer-type platinum(II) metal complexes incorporating chirality, as well as the study of their physicochemical properties, have gained significant interest [18][19][20][21][22]. Such efforts

Symmetrical D–π–A–π–D indanone dyes: a new design for nonlinear optics and cyanide detection

• Ergin Keleş,
• Alberto Barsella,
• Nurgül Seferoğlu,
• Zeynel Seferoğlu and
• Burcu Aydıner

Beilstein J. Org. Chem. 2026, 22, 131–142, doi:10.3762/bjoc.22.6

• 10.3762/bjoc.22.6 Abstract Three indan-2-one-based donor–π–acceptor–π–donor type dyes with symmetric donor groups were synthesized and characterized to study their nonlinear optical (NLO) properties and their potential use in the rapid and selective determination of cyanide. The designed structures

• colorimetric and optical changes. Because of the strong donor–acceptor structure, second-order NLO properties were studied by measuring electric field-induced second harmonic (EFISH) values, which showed significant second-order NLO responses. The experimental results were explained using density functional

• theory (DFT) methods. The dyes also exhibit chemosensor properties, showing selectivity for cyanide via a Michael addition mechanism that causes the disappearance of the ICT band, and a significant color change was observed in both organic and aqueous media. In addition, the interaction mechanism between