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

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

• were ultimately elucidated in 1968 by Wiesner and co-workers using a combination of chemical degradation and X-ray crystallography [14]. Notably, in 2016, Inoue’s group at the University of Tokyo reconciled discrepancies through comparative analysis of experimental and natural product data, confirming

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

Rapid access to the core of malayamycin A by intramolecular dipolar cycloaddition

• Yilin Liu,
• Yuchen Yang,
• Chen Yang,
• Sha-Hua Huang,
• Jian Jin and
• Ran Hong

Beilstein J. Org. Chem. 2025, 21, 2542–2547, doi:10.3762/bjoc.21.196

• 19 was moderate because the anomeric carbon at C7 is associated with an acid-sensitive acetonide group. The structural determination of the major product 19a was accomplished by comprehensive NMR spectroscopy and further unambiguously confirmed by X-ray analysis (see Supporting Information File 1 for

• the Baeyer–Villiger reaction. Supporting Information Supporting Information File 14: Experimental procedures and compound characterization data. Acknowledgements We thank Dr. Min Shao (Shanghai University) for assistance of X-ray analysis. Funding Financial support from the National Natural Science

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

• along with comparator H2 as solid-state sequestrants for a panel of five dyes (methylene blue, methylene violet, acridine orange, rhodamine 6G, and methyl violet 6B). We find that catechol-walled H2 (OH substituents) is a superior sequestrant compared to G2W1–G2W4 (OMe substituents). X-ray crystal

• complete within 10 minutes. Keywords: cucurbituril; dyes; sequestrants; X-ray crystallography; Introduction The needs of a growing world population and the demands of modern life has resulted in the increased production of both known and new chemical substances including building materials, vitamins and

• (Figure 2) from water. Subsequently, we present the X-ray crystal structures of G2W1 and G2W3 which helps rationalize the results from the dye sequestration experiments. Finally, we present a detailed investigation into the methylene blue removal efficiency using H2 [39] (Figure 1) and the methylene

A chiral LC–MS strategy for stereochemical assignment of natural products sharing a 3-methylpent-4-en-2-ol moiety in their terminal structures

• Rei Suo,
• Raku Irie,
• Hinako Nakayama,
• Yuta Ishimaru,
• Yuya Akama,
• Masato Oikawa and
• Shiro Itoi

Beilstein J. Org. Chem. 2025, 21, 2243–2249, doi:10.3762/bjoc.21.171

• terminal position of various polyketide natural products such as a series of azaphilones including chaetomugilins [14], chaetoviridins [14][15], and some other α-pyrone polyketides [16][17][18] (Figure 1). Among the available strategies for elucidating the stereochemistry of MPO, X-ray crystallographic

• analysis, and computational methods have been widely used. For example, the absolute configuration of chaetomugilin B [19] was determined by X-ray crystallography, while that of capsulactone (1) was established through density functional theory (DFT)-based simulations of NMR chemical shifts and electronic

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

• variety of new tri-, tetra- and pentacyclic ring systems. The structural characterization of (E)- and (Z)-hydrazones was supported by 2D NMR techniques, while that of the target compounds by single-crystal X-ray measurements. The hydrazone intermediates and the new title compounds were subjected to a

• 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

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

• were recorded on a Jeol ECP400 spectrometer (400 MHz) and a Bruker AVANCE II spectrometer (400 MHz). All NMR spectroscopic data of CDCl3 solutions are reported in ppm (δ) downfield from TMS. UV and CD spectra were recorded on JASCO V-650 and JASCO J-820 spectrometers, respectively. X-ray single-crystal

• , and X-ray structure of (S)-2b. Supporting Information File 10: Crystallographic information file for compound 2b. Funding This work was partly supported by JSPS KAKENHI (Grant No. 17K05845, 24K08368).

The application of desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds in the total synthesis of terpenoid and alkaloid natural products

• Dong-Xing Tan and
• Fu-She Han

Beilstein J. Org. Chem. 2025, 21, 2085–2102, doi:10.3762/bjoc.21.164

• ,8R,11R based on the X-ray single-crystal analysis of its corresponding p-bromobenzoic ester (not shown). Total synthesis of (−)-conidiogenones B–F and (−)-12β-hydroxyconidiogenone C Conidiogenones are unique diterpenoids which possess a highly congested 6/5/5/5-fused framework with four all-carbon

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

• subsp. brachystachys, and discovered a series of complex natural products named sargalmides A–E [43] (Scheme 7a). To clearly elucidate the complex structures, Yue and co-workers used multiple methods including extensive spectroscopic analysis (NMR, IR and MS), X-ray crystallography, quantum-chemical

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

• control of the reaction, while oxygen-bridged heterocycles 4 are formed under thermodynamic control. The purity and structure of compounds 4 and 5 were established by elemental analysis, mass spectrometry, 1H and 13C NMR spectroscopy, and X-ray diffraction study (Figure 1). For example, the 1H NMR spectra

• acids. The reaction under ultrasonication at room temperature yields a mixture of the latter with 5-(2-hydroxyphenyl)-7-hydroxy-2-(methylthio)-4,5,6,7-tetrahydro[1,2,4]triazolo[1,5-a]pyrimidine-7-carboxylic acids. Molecular structure of compound 4c according to X-ray diffraction data. Thermal ellipsoids

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

• and 13C NMR spectroscopy, and by X-ray diffraction study (see Experimental part). The 1H NMR spectra of compounds 5 are characterized by the following signals: a broad carboxyl group proton singlet at 12.10–12.17 ppm, an NH group proton singlet at 7.74–8.02 ppm, an aromatic protons multiplet at 6.52

• shift of the signal in the 198 ppm region, corresponding to the carbonyl carbon of compounds 8, to a stronger field in quinoxalinones 9, where cyclization of the keto group has occurred. The structure of quinoxalinones of type 9 was finally assigned based on X-ray diffraction analysis made for 3-(4-(2

• biologically active quinoxalinone derivatives. Molecular structure of 3-(4-(2-(tert-butylamino)-1-(4-methoxyphenyl)-2-oxoethyl)-5,7-dimethyl-3-oxo-3,4-dihydroquinoxalin-2-yl)propanoic acid (9e) according to X-ray diffraction data. Known multicomponent reactions of KGA. Ugi reaction involving KGA. Tandem Ugi

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

• aminopentynes 16a–c underwent allylic rearrangement, affording tetrahydropyridines 9 (Scheme 6). The tetrahydropyridine core was confirmed unambiguously by X-ray structure analysis of dinitrobenzamide 9c. More electron-rich acylamides reacted faster and gave less side-products, compared to more electron-poor

• . Conditions screening for copper-catalyzed arylation–cyclization of propargylsilane 7d. Supporting Information Supporting Information File 4: Experimental data, synthesis procedures, 1H and 13C NMR spectra, and X-ray data. Funding This work was supported by the Latvian Council of Science Grant LZP-2023/1

Enantioselective desymmetrization strategy of prochiral 1,3-diols in natural product synthesis

• Lihua Wei,
• Rui Yang,
• Zhifeng Shi and
• Zhiqiang Ma

Beilstein J. Org. Chem. 2025, 21, 1932–1963, doi:10.3762/bjoc.21.151

• confirmed by X-ray crystallographic analysis. Comparative analysis of the 1H NMR data with authentic samples of the natural heliannuol G and heliannuol H enabled structural revision of these compounds, correcting prior misassignments in the literature [31][32]. Through enzyme-catalyzed asymmetric

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

• Road, Hong Kong, China Materials Innovation Institute for Life Sciences and Energy (MILES), HKU-SIRI, Shenzhen, China 10.3762/bjoc.21.149 Abstract A series of nitrogen (N)-doped macrocycles was successfully synthesized through palladium-catalyzed arylation. X-ray crystallographic characterization

• introduced. In contrast, when bulky 3,5-bis(trifluoromethyl)phenyl groups were introduced, only inherent chiral macrocyclic products (MC3) were obtained in high yield. Their molecular structures are unambiguously characterized by NMR, mass spectra and X-ray crystallographic characterization. In addition

• 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

• purified through flash column chromatography on silica gel to give the isolated pure product. X-ray determined structure of chiral piperazine 2b. Synthesis of vicinal diamines via imino-pinacol coupling in the presence of metal-based reductants. Light-promoted imino-pinacol coupling for the synthesis of

• 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

• 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

• : ENaCt protocols, X-ray diffraction data for 5a, and NMR spectra for novel compounds. Acknowledgements We would like to thank Craig Robertson (University of Sheffield) and the EPSRC UK National Crystallography Service for access to ENaCt technology and the collection of associated crystallographic data

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

• ). Powder X-ray diffraction (PXRD) confirmed that crystallinity was preserved even after complete functionalization of DPG (Figure S8, Supporting Information File 1). To test the catalytic behavior of our amine-based lipophilic MOF catalysts, we chose the Knoevenagel condensation between benzaldehyde and

[3 + 2] Cycloaddition of thioformylium methylide with various arylidene-azolones in the synthesis of 7-thia-3-azaspiro[4.4]nonan-4-ones

• Daniil I. Rudik,
• Irina V. Tiushina,
• Anatoly I. Sokolov,
• Alexander Yu. Smirnov,
• Alexander R. Romanenko,
• Alexander A. Korlyukov,
• Andrey A. Mikhaylov and
• Mikhail S. Baranov

Beilstein J. Org. Chem. 2025, 21, 1791–1798, doi:10.3762/bjoc.21.141

• relative configuration (cis or trans) of the substituents. Therefore, the structures of the obtained compounds were determined by single crystal X-ray analysis (Figure 1). Thus, all the obtained derivatives of oxo-rhodanine 6, rhodanine 8 and imidazolone 9 had a cis configuration, while the derivatives of

• would be of help in further drug design of spirocyclic scaffolds. Single crystal X-ray analysis for the compounds 6e (A), 7d (B), 8e (C) and 9e (D). Atoms are shown as thermal ellipsoids at 50% probability. All hydrogen atoms, except the one at the stereogenic center, are omitted for clarity. Synthetic

• . Optimization of the reaction conditionsa. Supporting Information Supporting Information File 22: Experimental part, X-ray data and copies of NMR spectra. Acknowledgements A.A. Korlyukov and A.R. Romanenko are grateful to Ministry of Science and Higher Education of the Russian Federation (Contract No. 075

Unique halogen–π association detected in single crystals of C–N atropisomeric N-(2-halophenyl)quinolin-2-one derivatives and the thione analogue

• Mai Uchibori,
• Nanami Murate,
• Kanako Shima,
• Tatsunori Sakagami,
• Ko Kanehisa,
• Gary James Richards,
• Akiko Hori and
• Osamu Kitagawa

Beilstein J. Org. Chem. 2025, 21, 1748–1756, doi:10.3762/bjoc.21.138

• vapour diffusion of hexane into a methanol solution of the compound at room temperature) and their X-ray crystal structural analyses were performed (Figure 2) [33]. In the crystals of rac-1a, a π-type intermolecular interaction between the bromine atom and the benzene ring of the quinolinone was found

• electron pair on the bromine atom and a π* orbital of the quinoline-thione ring, rather than a π-type halogen bonding. Although we attempted the preparation of single crystals of the optically pure form of 2a, unfortunately, crystals suitable for X-ray measurement could not be obtained (2a is chemically

• their spectral data, copies of 1H and 13C{1H} NMR charts of compounds 1–4, chiral MPLC and HPLC chart in compounds 1a,b, 2a, evaluation of rotational barriers of compounds 1a,b, and X-ray crystal data of rac-1a,b, (P)-1a,b, rac-2a (check CIF). Funding This work was partly supported by JSPS KAKENHI (C

3,3'-Linked BINOL macrocycles: optimized synthesis of crown ethers featuring one or two BINOL units

• Somayyeh Kheirjou,
• Jan Riebe,
• Maike Thiele,
• Christoph Wölper and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2025, 21, 1719–1729, doi:10.3762/bjoc.21.134

• ). The structure of Me-M16 was additionally verified by single-crystal X-ray analysis (the enantiomeric compound (R)-Me-M16 resulting from a separate synthesis was crystallized, see Figure 4). Due to the macrocyclic structure, the two ethylene glycol units directly attached to each dimethylphenyl linker

Structural analysis of stereoselective galactose pyruvylation toward the synthesis of bacterial capsular polysaccharides

• Tsun-Yi Chiang,
• Mei-Huei Lin,
• Chun-Wei Chang,
• Jinq-Chyi Lee and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2025, 21, 1671–1677, doi:10.3762/bjoc.21.131

• biomolecules in organisms. However, the R/S stereochemistry of pyruvate ketal is difficult to control through chemical methods. In this study, the acid-labile pyruvate ketal linked to the 4- and 6-positions of galactose was cautiously constructed, and the X-ray analysis of the R-configured product was

• successfully obtained. Subsequently, the compound was used for the synthesis of zwitterionic polysaccharide A1 (PS A1) precursor, and a clear structural elucidation was applied by using nuclear magnetic resonance and X-ray. Keywords: carbohydrates; capsular polysaccharides; diastereochemistry; glycosylation

• confirming their structure by using X-ray crystallography as direct evidence. Subsequently, the pyruvylated galactose was further applied in the synthesis of zwitterionic polysaccharide A1 (PS A1) precursor. Results and Discussion In the initial experiment, p-tolyl 2,3-di-O-acetyl-1-thio-β-galactopyranoside

3-Aryl-2H-azirines as annulation reagents in the Ni(II)-catalyzed synthesis of 1H-benzo[4,5]thieno[3,2-b]pyrroles

• Julia I. Pavlenko,
• Pavel A. Sakharov,
• Anastasiya V. Agafonova,
• Derenik A. Isadzhanyan,
• Alexander F. Khlebnikov and
• Mikhail S. Novikov

Beilstein J. Org. Chem. 2025, 21, 1595–1602, doi:10.3762/bjoc.21.123

• Centre for X-ray Diffraction Studies, the Centre for Chemical Analysis and Materials, and the Centre for Optical and Laser Materials Research of the Science Park of St. Petersburg State University. Funding This work was supported by Russian Science Foundation Grant No. 23-13-00115.