Electrochemical reduction of unsaturated carbon–carbon bonds via 3d transition-metal catalysis

• Geon Kang,
• Minki Jeon,
• Pooja Kumari Jat,
• Cheoljae Kim and
• Isaac Choi

Beilstein J. Org. Chem. 2026, 22, 955–981, doi:10.3762/bjoc.22.75

• tandem electrocatalysis essential for productive reactivity. During controlled-potential electrolysis, a characteristic color change of the solution was observed, and formation of an electrogenerated Fe(I) species was unambiguously confirmed by X-ray diffraction analysis and UV–vis spectroscopy in the

Recent advances in copper-catalyzed direct hydroamination of alkenes with (hetero)aromatic amines

• Hyejeong Lee and
• Yunmi Lee

Beilstein J. Org. Chem. 2026, 22, 925–947, doi:10.3762/bjoc.22.73

• CuCo2O4 catalyst was prepared via an oxalate decomposition method and extensively characterized using powder X-ray diffraction, field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy. Structural analysis revealed the formation of microsheet-like architectures with high

Cascade transformation of 2-(diazoacetyl)-2H-azirines to 2-aroyl-3-hydroxy-1H-pyrroles via condensation with aromatic aldehydes

• Timur O. Zanakhov,
• Ekaterina E. Galenko,
• Mikhail S. Novikov and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2026, 22, 897–904, doi:10.3762/bjoc.22.70

• Centre for Magnetic Resonance, the Research Centre for X-ray Diffraction Studies, the Centre for Chemical Analysis and Materials, Centre for Optical and Laser Materials Research and the Computer Centre of the Science Park of St. Petersburg State University. Funding This work was supported by the Russian

Chiral cyclopropenimine-catalyzed enantioselective Michael reactions of phenol and benzofuran-derived α,β-unsaturated pyrazolamides with benzophenone-imine of glycine esters

• Ya Bai,
• Xue-Ying Wang,
• Si-Kai Zhu,
• Yan-Ting Shen,
• Sheng-Yong Zhang and
• Ping-An Wang

Beilstein J. Org. Chem. 2026, 22, 888–896, doi:10.3762/bjoc.22.69

• in high yields and excellent ee values (Scheme 4) To our delight, 3-substituted pyroglutamic acid ester 7d’ was obtained as single crystals for X-ray diffraction analysis [15]. The ester group and the bromophenoxymethyl group were arranged on the other side of the pyrrolidinone ring to be in trans

• benzophenone-imine esters. The catalysts used in the screening of Michael reaction conditions. The proposed attack modes of Michael addition of 2a and 5a. A proposed reaction mechanism of CSB-1 catalyzed Michael reaction between 2a and 5a. Configuration of 7d’ determined by X-ray diffraction analysis. Chiral

The trans-influence in gold chemistry from a catalytic perspective

• Manfred Bochmann

Beilstein J. Org. Chem. 2026, 22, 838–856, doi:10.3762/bjoc.22.66

• auto-accelerating radical chain mechanism, to give a stable hydroperoxide complex 23 that was characterised by X-ray diffraction. This reaction was greatly accelerated by AIBN as radical initiator which generates Au(II) radical cations [(P^C^P)Au]+•, as well as RO• and ROO• radicals, which propagate

• ligands is to consider the structure of the recently described π-allyl complexes 26–28 (Scheme 14) [80][81][82][83]. Compounds 26 and 27 were characterised by X-ray diffraction and NMR spectroscopy, which showed that 26 is fluxional. The dication 28 was spectroscopically identified and the structure

Unsymmetrical sulfoxides with sterically hindered catechol fragment: synthesis, structure, electrochemical properties, and antiradical activity

• Daria A. Burmistrova,
• Vasiliy A. Fokin,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Maxim V. Arsenyev,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2026, 22, 828–837, doi:10.3762/bjoc.22.65

• crystallographic parameters and X-ray diffraction experimental parameters are given in Supporting Information File 1, Table S1. Compound 4a crystallizes as a solvate with hexane in a ratio of two crystallographically independent molecules. In the monoclinic crystal of compound 5a, two independent molecules were

• thioethers. Single-crystal X-ray diffraction analysis of catechol sulfoxides containing isopropyl, cyclopentyl, adamantyl, benzyl, and 1-naphthyl groups, combined with NMR and IR spectroscopy, revealed a consistent tendency of these sulfoxides to form intra- and intermolecular O–H···O=S hydrogen bonds both

Synthesis and structural elucidation of a novel bis-spirooxindole from isatin and ethylenediamine

• Irene Moreno-Gutiérrez,
• Josefa L. López-Martínez,
• Sonia Berenguel-Gómez,
• Irene Torres-García,
• Duane Choquesillo-Lazarte,
• Manuel Muñoz-Dorado,
• Miriam Álvarez-Corral and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2026, 22, 813–820, doi:10.3762/bjoc.22.63

• single-crystal X-ray diffraction. In addition, the isolated diiminoisatin can be independently reduced to the same bis-spirooxindole. These results broaden the scope of isatin–diamine condensations and demonstrate their potential to generate structurally complex spirooxindole architectures under simple

• -proline (7), which leads to the formation of the dispirocyclic product 9 whose structure was ultimately established by X-ray diffraction after initial ambiguity based on spectroscopic data alone (Scheme 1) [16][17]. This case illustrates how condensations of isatin with bifunctional nitrogen nucleophiles

• . Single-crystal X-ray diffraction analysis confirmed the structure of 25 unambiguously. The ORTEP representation (Figure 2) shows two oxindole units arranged orthogonally and connected by a central six-membered piperazine ring, with both isatin C-3 atoms converted into nitrogen-bearing spiro centers. The

Knoevenagel condensation of 4,5- and 1,8-diazafluorenes

• Darya S. Cheshkina,
• Christina S. Becker,
• Alina A. Sonina and
• Maxim S. Kazantsev

Beilstein J. Org. Chem. 2026, 22, 803–812, doi:10.3762/bjoc.22.62

• about 3 days. The crystals of Zn-4,5-DPDAF (Zn–4,5-DPDAF) were grown by layering a near-saturated ZnCl2 solution in CH3OH over the CHCl3 solution of 4,5-DPDAF. The crystal growth time was about 2 weeks. Single-crystal X-ray diffraction experiments were performed at 296(2) K using a Bruker KAPPA APEX II

Synthesis of depressin, cryptomeridiol and 4-epi-cryptomeridiol enabled by a terpenoid chiral pool-producing platform

• Yao Kong,
• Tao Wang,
• Chen Wang,
• Pengcheng Zhang,
• Yuanning Liu,
• Kaibiao Wang,
• Fen Liu,
• Hongli Jia and
• Zhengren Xu

Beilstein J. Org. Chem. 2026, 22, 683–690, doi:10.3762/bjoc.22.53

• derivative 16 (CCDC 2470579) as a brownish-yellow needle suitable for X-ray diffraction (Scheme 2b) [56][57], which confirmed the absolute configuration of the casbene skeleton and the position of the first allylic oxidation. It is also interesting to note that the three double bonds in this molecule are

• -cryptomeridiol (3). Synthesis of depressin (1), cryptomeridiol (2), and 4-epi-cryptomeridiol (3). a) Synthetic route of 1 starting from casbene (4). b) Preparation of 2,4-nitrophenylhydrazone derivative of 13-ketocasbene (9) for X-ray diffraction. c) Synthetic route of 2 and 3 starting from germacrene A (5

Melifoliox B, a novel phloroglucin derivative isolated from Melicope barbigera (Rutaceae) and synthesis of new oxidation products from melifoliones A and B

• Horst Weber,
• Kim-Thao Tran-Cong,
• Bernhard Mayer,
• Guido J. Reiss,
• Iryna S. Konovalova,
• Marc S. Appelhans,
• Kenneth R. Wood and
• Claus M. Passreiter

Beilstein J. Org. Chem. 2026, 22, 535–546, doi:10.3762/bjoc.22.39

• addition to 11 DMF and an isomeric compound 12 were identified in the unit cell (Figure 3). Single-crystal X-ray diffraction data were collected for all samples using a Synergy diffractometer (Rigaku Oxford Diffraction) equipped with a photon-counting detector system [15]. Despite careful selection and

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

• structurally characterised by single-crystal X-ray diffraction analysis. The anticancer potential of the NAP-SePh and NAP-Se(n-Oct) was evaluated using an in vitro cell viability assay with MDA-MB-231 triple-negative breast cancer (TNBC) cells. The IC₅₀ values for compounds NAP-SePh and NAP-Se(n-Oct) were

• . However, as shown in Supporting Information File 1, Figure S19, a representative fragment ion with a m/z value of 318.0028 could be matched with naphthalimide selenenium cation, having a calculated m/z value of 318.0028. Single-crystal X-ray diffraction analysis of compound 7 A single crystal of compound

• 7 was obtained by slow evaporation of a chloroform–methanol mixture (1:3 v/v). Single-crystal X-ray diffraction analysis revealed that compound 7 crystallises in the triclinic crystal system with the space group . The crystal structure of compound 7 is shown in Figure 2a. It shows a typical V-shaped

Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities

• Ilia Korniltsev,
• Vasily Bazhenov,
• Alexander Gorbunov,
• Dmitry Cheshkov,
• Stanislav Bezzubov,
• Vladimir Kovalev and
• Ivan Vatsouro

Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28

• calixarene 12, which is additional evidence for its structure. The structure of trinitrated calix[4]arene 16 having a single TBS-protected propargyl group at the narrow rim was unambiguously established from X-ray diffraction data. Suitable crystals were collected upon slow evaporation of a dichloromethane

• determined using 2D NMR and X-ray diffraction data, contributing to a general understanding of the selectivity of nitration when applied to calixarenes containing bulky narrow-rim substituents. The functionalization capabilities of the propargylated/2-azidoethylated p-aminocalix[4]arenes were demonstrated by

• Supporting Information File 18: Synthesis details, copies of 1H and 13C NMR spectra of novel compounds, details of X-ray diffraction measurements and crystal structure data. Supporting Information File 19: Crystallographic information file for compound 16. Supporting Information File 20: Crystallographic

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

• X-ray diffraction analysis (XRD) for two adducts, followed by Hirshfeld surface analysis. The antiproliferative effect of the synthesized compounds against cancer cell lines was assessed. Keywords: alloxan; antiproliferative activity; azomethine ylides; 1,3-dipolar cycloaddition; maleimides

• Information File 38: General information, experimental procedures, characterization data, X-ray data and biological activity data. Acknowledgements This research made use of resources from the Centre for Magnetic Resonance, X-ray Diffraction Centre, Centre for Chemical Analysis and Materials of Saint

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

• Abstract A twisted D–π–A molecule, PI-Cz 1, was designed and synthesized using phthalimide as the acceptor, carbazole as the donor, and a phenylene bridge. Single-crystal X-ray diffraction revealed a markedly non-coplanar skeleton. Calculations based on the crystallographic geometry and frontier-orbital

• obtained through the method of slow solvent evaporation, which allows for the formation of high-quality crystals suitable for detailed structural analysis. The crystal structure of 1 was thoroughly characterized using single-crystal X-ray diffraction (CCDC 2492630). This technique provides precise three

• Figure 5b. This indicates that the specific molecular arrangement necessary for RTP was disrupted upon melting and subsequent rapid cooling, suggesting that the ordered structure in the solid phase is essential for the RTP phenomenon. In addition to the optical measurements, powder X-ray diffraction

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

• solid form Crystals of 1·HCl were grown from an ethanolic solution, and the crystal structure was determined by single-crystal X-ray diffraction (SCXRD, Figure 2). As seen in Figure 2a, 1·HCl adopts a twisted U shape and is involved in three hydrogen bonds. Therein, the ammonium N atom interacts with

• : Further details on SCXRD, deuterium isotope effects, and NMR spectra. Acknowledgements The technical assistance of Mr. Niels Vissing Holst, Department of Chemistry, University of Copenhagen, with collecting X-ray diffraction data and data processing is gratefully acknowledged. Funding This work was

• (4 °C) overnight, the solids were collected by vacuum filtration and dried under high vacuum. In this way, approximately 60% of the starting material was recovered as a white solid. SCXRD Crystals of 1·HCl were grown by slow evaporation of a solution in EtOH at rt. A single crystal suitable for X-ray

Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure

• Ilia A. Pilipenko,
• Mikhail V. Grigoriev,
• Olga Yu. Ozerova,
• Igor A. Litvinov,
• Darya V. Spiridonova,
• Aleksander V. Vasilyev and
• Sergey V. Makarenko

Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5

• bromine. The cyclization step from this conformation leads to trans-cyclopropanes. X-ray diffraction analysis data for compounds 2, 3, 9a, and 9b convincingly confirm the accepted structures, the position of cyclopropane protons, and the relative configurations of asymmetric atoms (Figures 2–5). It should

• be noted that the lengths of the C1–C2 (1.470(2)–1.491(4) Å) and C2–NO2 (1.472(4)–1.486(2) Å) bonds according to X-ray diffraction analysis in the molecules of nitrocyclopropanes 2, 3, 9a, and 9b turn out to be close to those in the molecules of nitrospirocyclopropanecarboxylates (C1–C2 (1.464(1

• -crystal X-ray diffraction analysis. Experimental Physicochemical studies were performed using the equipment of the Center for Collective Use "Physicochemical methods for the study of nitro compounds, coordination, biologically active substances and nanostructured materials" of the Interdisciplinary

Competitive cyclization of ethyl trifluoroacetoacetate and methyl ketones with 1,3-diamino-2-propanol into hydrogenated oxazolo- and pyrimido-condensed pyridones

• Svetlana O. Kushch,
• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess,
• Pavel A. Slepukhin,
• Alexandrina S. Volobueva,
• Vladimir V. Zarubaev and
• Victor I. Saloutin

Beilstein J. Org. Chem. 2025, 21, 2716–2729, doi:10.3762/bjoc.21.209

• , causes the formation of two to four diastereomers, the structure of which has been determined with 1H, 19F, 13C, 2D 1H-13C HSQC/HMBC, 1H-1H COSY/NOESY NMR and X-ray diffraction analysis. Keywords: condensed pyridones; 1,3-diamino-2-propanol; ethyl 4,4,4-trifluoroacetoacetate; methyl ketones; three

• octahydropyrido[1,2-a]pyrimidinones 4a–d and hexahydrooxazolo[3,2-a]pyridones 5a–c was determined by IR, 1H, 19F, 13C NMR spectroscopy, two-dimensional NMR experiments, and X-ray diffraction analysis (XRD). The IR spectra of octahydropyrido[1,2-a]pyrimidinones 4a–d are characterized by reduced vibrational

Tandem hydrothiocyanation/cyclization of CF₃-iminopropargyl alcohols with NaSCN in the presence of AcOH

• Ruslan S. Shulgin,
• Ol’ga G. Volostnykh,
• Anton V. Stepanov,
• Igor’ A. Ushakov,
• Alexander V. Vashchenko and
• Olesya A. Shemyakina

Beilstein J. Org. Chem. 2025, 21, 2694–2702, doi:10.3762/bjoc.21.207

• and X-ray diffraction. Synthesis of isothiazolium thiocyanates 2 and 4-thiocyanato-2,5-dihydrofuran-2-amines 3. Typical procedure. A solution of iminopropargyl alcohol 1 (0.5 mmol, 1 equiv) in 3 mL of acetonitrile was quickly added to a mixture of sodium thiocyanate (1 mmol, 2 equiv) and 1 mL of

Synthesis of new tetra- and pentacyclic, methylenedioxy- and ethylenedioxy-substituted derivatives of the dibenzo[c,f][1,2]thiazepine ring system

• Gábor Berecz,
• András Dancsó,
• Mária Tóthné Lauritz,
• Loránd Kiss,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2645–2656, doi:10.3762/bjoc.21.205

• step for the construction of the ring systems has been implemented by an intramolecular Friedel–Crafts cyclization. Altogether eight new ring systems are described here, five of them are also characterized by single-crystal X-ray diffraction. Keywords: acylation; bridged derivatives; cyclization

• , respectively (Scheme 2). The structure of compounds 20e and 21g was also confirmed by single-crystal X-ray diffraction (Figure 3). We demonstrated the potential utility of the synthesized new ring systems in the field of medicinal chemistry by the synthesis of tetracyclic analogues 20b and 21b of tianeptine

• of compound 23a was proven by single-crystal X-ray diffraction (Figure 4). Starting from compound 7, using methods we have previously developed for the synthesis of related compounds [2][3], we have now prepared new pentacyclic ring systems 25–27 (Scheme 5). Demethylation of 7 followed by alkylation

Ni-promoted reductive cyclization cascade enables a total synthesis of (+)-aglacin B

• Si-Chen Yao,
• Jing-Si Cao,
• Jian Xiao,
• Ya-Wen Wang and
• Yu Peng

Beilstein J. Org. Chem. 2025, 21, 2548–2552, doi:10.3762/bjoc.21.197

• single crystals, and a corresponding X-ray diffraction analysis (inset in Scheme 3, selected H atoms have been omitted for clarity, and Table S3, Supporting Information File 1) unambiguously confirmed its precise structure with three continuous chiral centers. Conclusion In summary, the total synthesis

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

• thoroughly characterized by 1H and 13C NMR spectroscopy, HRMS, and single-crystal X-ray diffraction analysis (Figure 1). A range of solvents was subsequently screened; however, none provided an improvement over 1,4-dioxane for this transformation (Table 1, entries 2 and 3). In addition to AgNO3, other silver

• of our method. Key mechanistic studies. Optimization studies.a Supporting Information Supporting Information File 9: Experiment details, characterization data, copy of NMR spectra of synthesized compounds, and single-crystal X-ray diffraction data. Supporting Information File 10: CIF file for 2a

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

• crystal structures by X-ray diffraction methods. Figure 5a shows a cross-eyed stereoview of one molecule of G2W3 in the crystal. Crystals of G2W3 are monoclinic with the P21/c space group (a/Å = 10.0768(9); b/Å = 13.4198(11); c/Å = 32.411(3); α/° = 90, β/° = 98.135(3), γ/° = 90). As has been observed

• substituents – provides a compelling explanation for the superior performance of H2 over G2W3 and G2W4. We were also fortunate to obtain single crystals of G2W1 (CCDC 2466610) and solve the structure by X-ray diffraction measurements. Crystals of G2W1 are triclinic with the P−1 space group (a/Å = 15.414(4); b

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

• closed vial in which the reaction is carried out does not contain the necessary amount of oxygen. Structure determination of the products was also supported by single-crystal X-ray diffraction in the case of several representatives: 3b, 3d, 3e, 3g, 3h, (E)-7a, 7b, 7d, 7e, (E)-7f, (Z)-7h, 7i, and (E)-9a

• F254 and by UHPLC–MS on a Shimadzu LC-40 UHPLC equipment equipped with a quaternary pump, degasser, autosampler, column oven, diode array detector, and an LCMS-2020 quadrupole mass spectrometer. Single-crystal X-ray diffraction (SC-XRD) measurements were carried out on a Rigaku R-Axis Spider

Further elaboration of the stereodivergent approach to chaetominine-type alkaloids: synthesis of the reported structures of aspera chaetominines A and B and revised structure of aspera chaetominine B

• Jin-Fang Lü,
• Jiang-Feng Wu,
• Jian-Liang Ye and
• Pei-Qiang Huang

Beilstein J. Org. Chem. 2025, 21, 2072–2081, doi:10.3762/bjoc.21.162

• the 13C NMR spectrum. We have succeeded in preparing a single crystal from the oxidation products. Interestingly, the X-ray diffraction analysis [66] showed that the single crystal contained two diastereomers (19/20) with the structures displayed in Scheme 2. Similarly, the DMDO oxidation of

Bioinspired total syntheses of natural products: a personal adventure

• Zhengyi Qin,
• Yuting Yang,
• Nuran Yan,
• Xinyu Liang,
• Zhiyu Zhang,
• Yaxuan Duan,
• Huilin Li and
• Xuegong She

Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160

• products capillosanol and chabranol, respectively [18]. Chabranol was identified to contain a new bridged skeleton through extensive NMR experiments. However, no single-crystal X-ray diffraction analysis was conducted, making the structural determinations not that solid. It showed moderate cytotoxicity

• the structure further, X-ray diffraction analysis of the derivative of bicycle 9 was obtained. This approach established the first total synthesis of chabranol in a concise way through the bioinspired Prins-triggered double cyclization strategy to rapidly construct the bicycle. Total syntheses of

• simple 1,4-benzoquinone to act as the dienophile, and the expected Diels–Alder reaction proceeded smoothly to provide the endo adducts 48a and 48b, in which 48b was the major product dominated by the isopropyl steric effect. Isomers 48a and 48b were separable and determined through X-ray diffraction