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

• crystals. The high-resolution mass spectrum gave a protonated mol peak at 279.1226 indicating the formula C15H19O5. Compared to melifoliones this means a loss of 3 C-atoms. Based on the NMR spectra (1H, 2D-COSY, 13C, HSQC, HMBC) the structure of the oxidation product was determined as the spirofuranone 11

• mounting of the crystals, all specimens exhibited weak and diffuse diffraction patterns, which significantly limited data quality. This behavior is attributed to poor crystallinity and partial disorder within the crystal, likely exacerbated by the gradual release of solvent molecules during sample handling

• , filtered and evaporated to dryness. The remaining residue was recrystallized from diethyl ether/hexane to give 2.3 g (77%) colorless crystals, containing about 90% melifolione A (1) (CAS: 59779-71-4) and 10% melifolione B (2) (CAS: 37464-54-3), based on the 1H NMR spectrum. NMR data see Table 1 and Table 2

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

• assayed each compound for inhibitory activity against the GAC isoform of glutaminase and found that the three compounds inhibited it with equal potency, further suggesting that the compounds are identical (Figure 3B). To unambiguously determine the structure of this compound, we grew crystals of our

• , 130.92, 129.02, 128.68, 128.12, 127.49, 124.25, 122.93, 120.88, 118.45, 117.59, 116.53, 107.43, 50.77, 44.22, 35.30, 32.80, 29.56, 27.06. X-ray crystallography Crystals of compound 2 were grown by slow evaporation from a saturated acetone solution. A yellow, multi-faceted block of suitable size (0.362

• × 0.124 × 0.064 mm3) and quality was selected from a representative sample of crystals of the same habit using an optical microscope, mounted onto a Mitegen MicroLoopsTM (MiTeGen, LLC., Ithaca, NY) and placed in a cold nitrogen stream of nitrogen. Low temperature (100 K) X-ray data were obtained on a

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

• coupling of compound 1ad with MeMgBr and PhMgBr in the presence of a catalytic amount of NiCl2(PPh3)2 proceeded smoothly to provide the C6-methyl-substituted 1ab in 79% yield and the C6-phenyl-substituted 1ac in 99% yield (Scheme 3) [15][16]. Suitable single crystals were obtained from racemic 1ac, and its

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

• exposure. After adding 1 mg/mL, 100 μL per well of MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide solution, the cells were incubated for 4 hours in a dark area. To dissolve the formazan crystals, 100 μL of DMSO was applied to each well after the media was carefully removed. After 40

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

• /methanol solution of compound 16. Similarly, single crystals of the exhaustively nitrated calix[4]arene 15 having two TBS-protected propargyl groups at the narrow rim were collected, and the molecular structure of this compound was also established (Figure 3) [94]. The results showed clearly, that in

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

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

• , the triplet exciton management and channel selectivity in different phases of PI-Cz 1 were systematically studied, validating the feasibility of “configuration-packing synergy” for controllable RTP–TADF switching within the same molecule. Results and Discussion Single crystals of 1 were successfully

• 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

• , an in-depth analysis was conducted on both the molecular structure and the packing arrangement in single crystals of 1. As depicted in Figure 6a, the crystal structure of 1 reveals the presence of significant π–π interactions between adjacent molecules. These interactions are crucial for stabilizing

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

• (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

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

• spectroscopy, as well as high-resolution mass spectrometry (HRMS). Due to its low solubility, single crystals suitable for X-ray crystallographic analysis could not be obtained. Spectroscopic analysis and DFT calculations To elucidate the electronic structure of the platinum(II) complex, UV–vis absorption

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

• obtained as a racemic diastereomeric pair 1SR,2RS. Centrosymmetric crystals 9a and 9b are diastereomers and crystallize as a true racemate. The configuration of the chiral atoms C1 and C2 in the molecules is the same as in molecules 2, and the difference is the configuration of atom C3. In crystal 9a, the

• enatiomeric pair S,R,S/R,S,R is realized, and in crystal 9b – S,R,R/R,S,S. The main geometric parameters (bond lengths and valence angles) and the conformation of independent molecules in crystals of 2, 3, 9a and 9b coincide within the experimental errors, so Figures 2–5 show the geometry of one of the

• independent molecules. Note that crystals 2, 3, 9a and 9b have a relatively high density (dcalc/g cm−3 1.739, 1.748, 1.595 and 1.567) for crystals that do not contain heavy atoms. In the absence of hydrogen bonds in the crystals of 2, 3, 9a and 9b, multiple specific interactions of the types such as lone

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

• the OH group. The crystal packing of single crystals 4att, 4atc, 4acc, 4act, 4dct is ordered by intermolecular hydrogen bonds linking O–H groups and heteroatoms O/N of neighboring molecules (see Table S8 in Supporting Information File 1); N–H groups of the hexahydropyrimidine ring and a carbonyl

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

• (thickness of the stationary phase: 30 mm, eluent: DCM). After evaporation of the solvent, the residue was triturated with Et2O (50 mL) to give pure 7 (25.30 g, 84%) as colorless crystals. Mp 223‒225 °C (CH3CN/EtOH 1:1 (v/v)); IR (KBr): 1638, 1604, 1574, 1501, 1354, 1300, 1175, 1063, 854 cm−1; 1H NMR (600

• chromatography (short aluminum oxide column, eluent: heptane/DCM 1:1, DCM) and isomer 8 (0.62 g, 2%) was isolated as pale yellow crystals. Mp 254‒256 °C (CH3CN); IR (KBr): 1665, 1485, 1344, 1111, 1061, 859 cm−1; 1H NMR (500 MHz, CDCl3): 7.96 (d, 4J = 2.0 Hz, 1H), 7.94 (d, 3J = 8.6 Hz, 1H), 7.63 (dd, 4J = 2.1 Hz

• -like hard substance obtained was suspended in DIPE to afford 21a as colorless crystals. Mp 76‒78 °C; IR (KBr): 3314, 2939, 1728, 1510, 1328, 1064, 853, 599 cm−1; 1H NMR (600 MHz, CDCl3): 7.94 (d, 4J = 1.9 Hz, 1H), 7.43 (dd, 4J = 2.1 Hz, 3J = 8.4 Hz, 1H), 7.39 (d, 3J = 8.4 Hz, 1H), 6.92 (s, 1H), 6.83 (s

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

• of the desired products. More decisively, a single crystal X-ray analysis was performed. Compounds 3n and 4n were provided with suitable crystals for X-ray structural analysis resulting in new crystal structures, Figure 4 and Figure S250 in Supporting Information File 1, respectively. The single

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

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

• methyl substituents (H2). Fortunately, the X-ray crystal structures of G2W1 and G2W3 reported below shed further light on their poor performance as solid state sequestrants. X-ray crystal structure of G2W1 and G2W3 Eventually, we were able to grow single crystals of G2W3 (CCDC 2466611) and solve their

• 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

• influenced by their tendency to form thermodynamically stable crystals since disruption of such stable structures is more challenging [37][38][39][40][41][42]. Molecules with symmetric elements and plane rings typically tend to form such stable crystals. The notable solubility difference of hydrazones 7a and

• products. 8-(2-Cyclohexylidenehydrazino)-2,4-dimethyl-2H-1,2,3-benzothiadiazine 1,1-dioxide (7e). Prepared according to the general procedure, using 5a and 6e as the starting materials. Yield: 111.0 mg (83%), yellow crystals. Mp 99–100 °C (EtOH); 1H NMR (600 MHz, DMSO-d6) δ 9.19 (br s, 1H), 7.80 (d, J

• to LC–MS). Pure (E)-7h was obtained by purification using flash chromatography (hexane–EtOAc). Yield: 45 mg (40%), colorless crystals. Mp 138–139 °C (EtOH); 1H NMR (600 MHz, DMSO-d6) δ 9.54 (br s, 1H), 7.80 (d, J = 8.6 Hz, 1H), 7.62 (m, 2H), 7.57 (m, 2H), 7.54 (m, 3H), 6.71 (d, J = 7.7 Hz, 1H), 3.47

A m-quaterphenyl probe for absolute configurational assignments of primary and secondary amines

• Yuka Takeuchi,
• Mutsumi Kobayashi,
• Yuuka Gotoh,
• Mari Ikeda,
• Yoichi Habata,
• Tomohiko Shirai and
• Shunsuke Kuwahara

Beilstein J. Org. Chem. 2025, 21, 2211–2219, doi:10.3762/bjoc.21.168

• configurations of both natural and synthetic compounds continues to pose a considerable challenge in the life and materials sciences [1]. While X-ray crystallography remains a reliable method for this purpose, the requirement for high-quality single crystals often limits its applicability. In recent years

Multicomponent reactions IV

• Thomas J. J. Müller and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2082–2084, doi:10.3762/bjoc.21.163

• Thomas J. J. Muller Valentyn A. Chebanov Heinrich-Heine-Universität Düsseldorf, Institut für Organische Chemie und Makromolekulare Chemie, Universitätsstraße 1, D-40225 Düsseldorf, Germany Institute of Functional Materials Chemistry, State Scientific Institution “Institute for Single Crystals” of

• is guest-edited by Thomas J. J. Müller (Heinrich Heine University Düsseldorf, Germany) together with Valentyn A. Chebanov (State Scientific Institution “Institute for Single Crystals” of the National Academy of Sciences of Ukraine, Kharkiv, Ukraine). The 30 contributions collected in this thematic

Switchable pathways of multicomponent heterocyclizations of 5-amino-1,2,4-triazoles with salicylaldehydes and pyruvic acid

• Yana I. Sakhno,
• Oleksander V. Buravov,
• Kostyantyn Yu. Yurkov,
• Anastasia Yu. Andryushchenko,
• Svitlana V. Shishkina and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2030–2035, doi:10.3762/bjoc.21.158

• Yana I. Sakhno Oleksander V. Buravov Kostyantyn Yu. Yurkov Anastasia Yu. Andryushchenko Svitlana V. Shishkina Valentyn A. Chebanov Institute of Functional Materials Chemistry, State Scientific Institution “Institute for Single Crystals” of National Academy of Sciences of Ukraine, Nauky Ave., 60

α-Ketoglutaric acid in Ugi reactions and Ugi/aza-Wittig tandem reactions

• Vladyslav O. Honcharov,
• Yana I. Sakhno,
• Olena H. Shvets,
• Vyacheslav E. Saraev,
• Svitlana V. Shishkina,
• Tetyana V. Shcherbakova and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2021–2029, doi:10.3762/bjoc.21.157

• Vladyslav O. Honcharov Yana I. Sakhno Olena H. Shvets Vyacheslav E. Saraev Svitlana V. Shishkina Tetyana V. Shcherbakova Valentyn A. Chebanov Institute of Functional Materials Chemistry, State Scientific Institution “Institute for Single Crystals” of National Academy of Sciences of Ukraine, Nauky

Synthesis of N-doped chiral macrocycles by regioselective palladium-catalyzed arylation

• Shuhai Qiu and
• Junzhi Liu

Beilstein J. Org. Chem. 2025, 21, 1917–1923, doi:10.3762/bjoc.21.149

• characterized by NMR spectroscopy, mass spectrometry, and X-ray crystallography. Single crystals suitable for X-ray diffraction measurements of compounds 3a, MC2, and MC3 were successfully obtained to reveal their molecular structures. In the crystal structure of 3a (Figure 2a), the two pyrene units are nearly

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

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

• rate of evaporation from a nanolitre solution of analyte encased within oil [33], suitable single crystals were obtained. The X-ray analysis allowed the determination of the relative stereochemistry, as shown in Figure 2. Compound 5a crystallised as a racemic mixture in the space group P21/c. The major

Chiral phosphoric acid-catalyzed asymmetric synthesis of helically chiral, planarly chiral and inherently chiral molecules

• Wei Liu and
• Xiaoyu Yang

Beilstein J. Org. Chem. 2025, 21, 1864–1889, doi:10.3762/bjoc.21.145

• molecular platforms in various applications, such as circularly polarized luminescence (CPL) materials, chiral liquid crystals and asymmetric catalysis. Currently, the asymmetric catalytic synthesis of helicenes predominantly revolves around transition metal-catalyzed asymmetric annulation reactions

Systematic pore lipophilization to enhance the efficiency of an amine-based MOF catalyst in the solvent-free Knoevenagel reaction

• Pricilla Matseketsa,
• Margret Kumbirayi Ruwimbo Pagare and
• Tendai Gadzikwa

Beilstein J. Org. Chem. 2025, 21, 1854–1863, doi:10.3762/bjoc.21.144

• , it is no surprise that PSM is a prevalent method for synthesizing MOF-based catalysts [30]. On this topic, our current work was inspired by Canivet et al. who previously reported the lipophilization of a MOF by grafting long alkyl chains to the external surfaces of its crystals. The active sites are