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

• 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

• . 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

• spectroscopic analysis and single-crystal X-ray diffraction. The same bis-spirooxindole 25 can be obtained by reduction of the diiminoisatin 24. The reaction with methyl-substituted isatin 29 follows the same pattern, affording 30. Overall, we have shown that simple isatin–diamine systems can deliver

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

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

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

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

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

• -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

• conditions. The reaction is carried out either in tetrahydrofuran in the presence of triethylamine or in methanol in the presence of fused potassium acetate. The structures of the isolated individual products were characterized by 1H and 13C NMR, IR spectroscopy, mass spectrometry, and confirmed by single

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

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

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

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

Stereoselective electrochemical intramolecular imino-pinacol reaction: a straightforward entry to enantiopure piperazines

• Margherita Gazzotti,
• Fabrizio Medici,
• Valerio Chiroli,
• Laura Raimondi,
• Sergio Rossi and
• Maurizio Benaglia

Beilstein J. Org. Chem. 2025, 21, 1897–1908, doi:10.3762/bjoc.21.147

• absolute configuration of the piperazine formed, a pure sample of compound 2b derived from (1R,2R)-trans-diaminocyclohexane was crystallized from a chloroform solution resulting in the formation of white crystals suitable for single crystal X-ray diffraction studies. The absolute configuration of the

• procedures and physical data for the new compounds, copies of 1H and 13C NMR spectra of the prepared compounds. Acknowledgements The authors thank Prof. A. Puglisi (Università degli Studi di Milano) for valuable discussions. For the single-crystal X-ray diffraction analysis the Unitech COSPECT (Università

Preparation of spirocyclic oxindoles by cyclisation of an oxime to a nitrone and dipolar cycloaddition

• Beth L. Ritchie,
• Alexandra Longcake and
• Iain Coldham

Beilstein J. Org. Chem. 2025, 21, 1890–1896, doi:10.3762/bjoc.21.146

• of an oxime, itself prepared in situ from an aldehyde. The stereochemistry of one of the spirooxindoles was determined by single crystal X-ray diffraction studies via crystallisation using encapsulated nanodroplet crystallisation (ENaCt) protocols. The chemistry involves cascade or tandem

Facile synthesis of hydantoin/1,2,4-oxadiazoline spiro-compounds via 1,3-dipolar cycloaddition of nitrile oxides to 5-iminohydantoins

• Juliana V. Petrova,
• Varvara T. Tkachenko,
• Victor A. Tafeenko,
• Anna S. Pestretsova,
• Vadim S. Pokrovsky,
• Maxim E. Kukushkin and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 1552–1560, doi:10.3762/bjoc.21.118

• -oxadiazolines [40]. Therefore, single crystal X-ray diffraction analysis is typically used to confirm the structure, as we have applied for the hydantoin/1,2,4-oxadiazoline spiro-compounds 5k (CCDC 2432465) and 5l (CCDC 2432466) (for details see Supporting Information File 1). The effect of the substituents on

• Ministry of Science and Higher Education of Russia no. 075-01551-23-00 (FSSF-2023-0006). Single crystal X-ray diffraction analysis study was supported by the RUDN University Scientific Projects Grant System, project №021408-2-000.

Ambident reactivity of enolizable 5-mercapto-1H-tetrazoles in trapping reactions with in situ-generated thiocarbonyl S-methanides derived from sterically crowded cycloaliphatic thioketones

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Marcin Palusiak,
• Heinz Heimgartner,
• Marta Denel-Bobrowska and
• Agnieszka B. Olejniczak

Beilstein J. Org. Chem. 2025, 21, 1508–1519, doi:10.3762/bjoc.21.113

• this product, without contamination with 10k, was feasible. Thioaminal 9i and dithioacetal 10i derived from 1-cyclohexyl-5-mercapto-4H-tetrazole (4b) could be isolated as stable, crystalline products and the postulated structures were unambiguously confirmed by the single crystal X-ray diffraction

Wittig reaction of cyclobisbiphenylenecarbonyl

• Taito Moribe,
• Junichiro Hirano,
• Hideaki Takano,
• Hiroshi Shinokubo and
• Norihito Fukui

Beilstein J. Org. Chem. 2025, 21, 1454–1461, doi:10.3762/bjoc.21.107

• byproduct and exhibited similar polarity as compound 5. The obtained compounds 3, 4, and 5 were identified using nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) (see Supporting Information File 1) as well as single crystal X-ray diffraction analysis (vide infra). Furthermore, the

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• in solution and structurally confirmed via single-crystal X-ray diffraction. It demonstrated the highest CPL performance among the series, with a |glum| value of 3.5 × 10−3 and a photoluminescence quantum yield (PLQY) of 0.31, indicating its potential as a chiral emissive material. Building upon this

Reactions of acryl thioamides with iminoiodinanes as a one-step synthesis of N-sulfonyl-2,3-dihydro-1,2-thiazoles

• Vladimir G. Ilkin,
• Pavel S. Silaichev,
• Valeriy O. Filimonov,
• Tetyana V. Beryozkina,
• Margarita D. Likhacheva,
• Pavel A. Slepukhin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2025, 21, 1397–1403, doi:10.3762/bjoc.21.104

• 2,3-dihydro-1,2-thiazole ring are in the range of 75.3–72.4 ppm and signals of the carbon atom of the cyano group in the range of 117.7–116.6 ppm. The structure of 2,3-dihydro-1,2-thiazole 3aa was additionally confirmed by single crystal X-ray diffraction (Figure 2). According to the X-ray diffraction

A multicomponent reaction-initiated synthesis of imidazopyridine-fused isoquinolinones

• Ashutosh Nath,
• John Mark Awad and
• Wei Zhang

Beilstein J. Org. Chem. 2025, 21, 1161–1169, doi:10.3762/bjoc.21.92

• , Supporting Information File 1), but it was not stable enough for isolation. The structure of 8a was confirmed by single crystal X-ray diffraction analysis. The optimized reaction conditions were used to evaluate the substrate scope of the synthesis of imidazopyridine-fused isoquinolinones 8 (Scheme 3). The

Studies on the syntheses of β-carboline alkaloids brevicarine and brevicolline

• Benedek Batizi,
• Patrik Pollák,
• András Dancsó,
• Péter Keglevich,
• Gyula Simig,
• Balázs Volk and
• Mátyás Milen

Beilstein J. Org. Chem. 2025, 21, 955–963, doi:10.3762/bjoc.21.79

• catalyst, overreduced product 31, i.e., the tetrahydro derivative of racemic brevicolline ((±)-1) was obtained in 91% yield. Structure determination of 31 was supported by single-crystal X-ray diffraction, as well (Figure 2). Changing the catalyst [Pd(OH)2, Ru, Rh], did not alter the course of the reaction

A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids

• Zhiyang Zhang,
• Jialei Hu,
• Hanfeng Ding,
• Li Zhang and
• Peirong Rao

Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75

• tricyclo[4.2.110,30.11,4]decane ring system. Additionally, krishnolides A and C contain 9–11 stereogenic centers and exhibit diverse oxidation patterns. Their relative and absolute configurations were determined through NMR, HRESIMS and ECD experiments, as well as single crystal X-ray diffraction analysis

Silver(I) triflate-catalyzed post-Ugi synthesis of pyrazolodiazepines

• Muhammad Hasan,
• Anatoly A. Peshkov,
• Syed Anis Ali Shah,
• Andrey Belyaev,
• Chang-Keun Lim,
• Shunyi Wang and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2025, 21, 915–925, doi:10.3762/bjoc.21.74

• trifluoromethyl and nitro groups. Furthermore, substrates 15m–o derived from aliphatic amines, also performed well, furnishing pyrazolodiazepines 16m–o in up to 89% yield. The structure of 16m, a representative compound of this series, was confirmed through single-crystal X-ray diffraction (scXRD) analysis

4-(1-Methylamino)ethylidene-1,5-disubstituted pyrrolidine-2,3-diones: synthesis, anti-inflammatory effect and in silico approaches

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Luc Van Meervelt,
• Do Thi Thao and
• Nguyen Minh Thong

Beilstein J. Org. Chem. 2025, 21, 817–829, doi:10.3762/bjoc.21.65

• spectroscopy, the structure of 4-(1-methylamino)ethylidene-1,5-diphenylpyrrolidine-2,3-dione (5a) was also verified through single-crystal X-ray diffraction. Furthermore, the synthesized molecules were evaluated for compliance with established drug-likeness rules (Lipinski, Veber, Ghose, Egan, and Muegge), as

• single-crystal X-ray diffraction [19]. According to a previous publication, the condensation between pyrrolidine-2,3-diones and an amine as nucleophile normally occurred at the 3-position of nitrogen-containing heterocyclic ring which results in the corresponding enamine product [18]. However, the

• -disubstituted pyrrolidine-2,3-diones were successfully synthesized via reversible transimination reaction. The structure of all compounds was evaluated using nuclear magnetic resonance (NMR) spectroscopy and, especially, with the molecular structure of compound 5a further confirmed through single-crystal X-ray

Cryptophycin unit B analogues

• Thomas Schachtsiek,
• Jona Voss,
• Maren Hamsen,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40

• control of equivalents and pH, or Leuckart–Wallach-like reaction with ammonium formate and Pd/C [25] provided monomethylaniline 7 in 37% and 35% yield, respectively. The absolute structure of monomethylaniline 7 was confirmed by single-crystal X-ray diffraction measurements (Figure 2). Compound 7

• conjugation handles in unit B. IC50 values given against (a) CCRF-CEM [20] and (b) KB-3-1 [21] cell lines. C: Cryptophycin-52 derivatives synthesised in this work. Molecular structure of Boc-ᴅ-Phe(4-NHMe)-OMe 7 as determined by single-crystal X-ray diffraction measurements. Thermal ellipsoids depicted at 50