Calcium waste as a catalyst in the transesterification for demanding esters: scalability perspective

• Anton N. Potorochenko and
• Konstantin S. Rodygin

Beilstein J. Org. Chem. 2025, 21, 1520–1527, doi:10.3762/bjoc.21.114

• of NMR spectra. Acknowledgements The authors gratefully acknowledge the Magnetic Resonance Research Centre, Centre for Chemical Analysis and Materials Research, X-ray Diffraction Research Centre of Research Park of Saint Petersburg State University. Funding This work was financially supported by

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

• ruled out. The structures of compounds 3, 4, and 5 were determined by X-ray diffraction analysis (Figure 2). Mono-olefin 3 and bis-olefin 5 adopt a bathtub-like chiral macrocyclic structure rather than figure-eight conformation. Both compounds crystallize as a racemic pair of enantiomers with P21/c and

• has been confirmed by X-ray diffraction analysis. On the other hand, the treatment of bis-olefin 5 under the same conditions recovered the starting material, which highlights the distinctive role of the carbonyl group for the reductive carbon–carbon-bond formation from 3. Conclusion The Wittig

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

Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

Selective monoformylation of naphthalene-fused propellanes for methylene-alternating copolymers

• Kenichi Kato,
• Tatsuki Hiroi,
• Seina Okada,
• Shunsuke Ohtani and
• Tomoki Ogoshi

Beilstein J. Org. Chem. 2025, 21, 1183–1191, doi:10.3762/bjoc.21.95

• heating process. T90 and CY of [3.3.3]_branch (415 °C and 64 wt %) were lower than those of [3.3.3]_linear because of two-step decay profile (Figure S703a in Supporting Information File 1). All the samples showed broad powder X-ray diffraction (PXRD) patterns with unclear peaks at around 2θ = 11° and 20

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

Gold extraction at the molecular level using α- and β-cyclodextrins

• Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

• desorption of KAu(CN)2. The ability of α-CD to strip gold from carbon was shown to result from the formation of inclusion complexes directly with the cyanoaurate ions, with (at least) two different stoichiometries of α-CD:KAu(CN)2, 1:1 and 2:2. Structural elucidation was achieved by isolation and X-ray

• diffraction of single crystals (Figure 3), showing, for both 1:1 and 2:1 stoichiometries, cyanoaurate anions inside the host cavity and potassium cations interacting with hydroxy groups of adjacent cyclodextrins. The strong host–guest affinity and complex stability in the solution phase has been studied by

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

Unraveling cooperative interactions between complexed ions in dual-host strategy for cesium salt separation

• Zhihua Liu,
• Ya-Zhi Chen,
• Ji Wang,
• Qingling Nie,
• Wei Zhao and
• Biao Wu

Beilstein J. Org. Chem. 2025, 21, 845–853, doi:10.3762/bjoc.21.68

• by the joint Cambridge Crystallographic Data Centre and Fachinformationszentrum Karlsruhe Access Structures service via https://www.ccdc.cam.ac.uk/. Supporting Information File 50: Nuclear magnetic resonance (NMR), mass and X-ray diffraction data. Acknowledgements We thank support from 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

Acyclic cucurbit[n]uril bearing alkyl sulfate ionic groups

• Christian Akakpo,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 717–726, doi:10.3762/bjoc.21.55

• hydrophobic region of the guest which changes the orientation of Ha with respect to the magnetically shielding region [54][63][64]. X-ray crystal structure of C1 We were fortunate to obtain single crystals of the C1·Me6CHDA complex and solved the crystal structure by X-ray diffraction (CCDC 2411723). Figure 5

Photochemically assisted synthesis of phenacenes fluorinated at the terminal benzene rings and their electronic spectra

• Yuuki Ishii,
• Minoru Yamaji,
• Fumito Tani,
• Kenta Goto,
• Yoshihiro Kubozono and
• Hideki Okamoto

Beilstein J. Org. Chem. 2025, 21, 670–679, doi:10.3762/bjoc.21.53

• -phenacenes for clarifying the different solid-fluorescence behavior between the parent and fluorinated phenacenes. Although we have extensively examined crystallization of F8-phenacenes, no single crystal suitable for an X-ray diffraction analysis was obtained. The crystalline structural analysis is still

Study of the interaction of 2H-furo[3,2-b]pyran-2-ones with nitrogen-containing nucleophiles

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2025, 21, 556–563, doi:10.3762/bjoc.21.44

• unambiguously confirmed by X-ray diffraction. Keywords: allomaltol; enamines; 2H-furo[3,2-b]pyran-2-ones; pyrazol-3-ones; recyclization; Introduction Substituted furan-2(5H)-ones (butenolides) are widely used as precursors for the preparation of diverse types of heterocyclic compounds possessing various

• units was isolated (Scheme 9). The structure of synthesized compound 13 was unambiguously confirmed by X-ray diffraction. Conclusion In summary, we studied the interaction of 2H-furo[3,2-b]pyran-2-one derivatives with various amines and hydrazines. It was demonstrated that, depending on the nature of

• structures of key synthesized products were unambiguously proved by X-ray diffraction. Various examples of transformations of furanones. Interaction of starting 2H-furo[3,2-b]pyran-2-ones with diverse amines. Synthesis of enamines 4. Reaction conditions: 1a (1 mmol, 0.38 g), amine 2 (1.2 mmol), AcOH (3 mL

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

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• ratio was found to be 1.74 (theoretical = 1.75), confirming the composition to be ANTH(BnF)2. Slow evaporation of a CH2Cl2 solution of 9,10-ANTH(BnF)2 at 2 °C afforded off-white plates suitable for X-ray diffraction. The structure shown in Figure 2 (top panel) confirmed the 9,10-substitution pattern

• -10-bis(perfluorobenzyl)anthracene were mounted in a paratone oil on glass fiber rods glued to a small copper wire. X-ray diffraction data were collected at ChemMatCARS (CARS = consortium for advanced radiation sources) sector 15-B at the Advanced Photon Source (Argonne National Laboratory). The data

Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• Figure 2b. We hypothesized that this reaction occurred in the solid state, and further investigations confirmed this. To validate our findings, we employed single-crystal X-ray diffraction, which revealed the packing mode in the crystal and identified any photoproducts formed. Two additional compounds

• included two additional bimane samples, Me2B and Me4B. These samples were crystallized from a MeOH–DCM 1:1 (v/v) mixture which was left to slowly evaporate over the course of several days at room temperature, followed by single-crystal X-ray diffraction to determine their structure (Figure 4) and crystal

• fluorescence spectrum and η is the refractive index of the solvent. Single crystal X-ray diffraction studies Crystals of Me4B, Cl2B (A), (B), (C), and Me2B were mounted on a MiTeGen micromount with NVH immersion oil. Data were collected from a shock-cooled single crystal at 100(2) K on a Bruker Apex Kappa Duo

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• determined. The structure of 2-(3,3-dimethyl-3H-benzo[g]indolin-2-yl)-5,6,7-trichloro-1,3-tropolone was determined by X-ray diffraction analysis. The compounds obtained are capable of switching emission at 420–440 nm and 476–530 nm upon successive exposure to CN− and Hg2+ ions in an acetonitrile solution. 2

• -(1,1-Dimethyl-1H-benzo[e]indolin-2-yl)-5,6,7-trichloro-1,3-tropolone exhibited high in vitro cytotoxic activity against A431 skin cancer and H1299 lung cancer cell lines. Keywords: cytotoxic activity; fluorescence; o-chloranil; quantum chemical DFT calculations; 1,3-tropolones; X-ray diffraction

• reaction of o-chloranil with benzoannelated derivatives of 2,3,3-trimethylindolenine, a comprehensive evaluation of the structure of the compounds obtained using quantum chemical methods, X-ray diffraction analysis, two-dimensional correlation NMR spectroscopy, as well as investigation of their ionochromic

Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates

• Kirill A. Gomonov,
• Vasilii V. Pelipko,
• Igor A. Litvinov,
• Ilya A. Pilipenko,
• Anna M. Stepanova,
• Nikolai A. Lapatin,
• Ruslan I. Baichurin and
• Sergei V. Makarenko

Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24

• of the synthesized compounds were proven by a set of physicochemical methods, including X-ray diffraction analysis. Keywords: CH-acids; 1-halo-1-nitroethenes; heterocyclization; nitroacrylates; X-ray diffraction analysis; Introduction The combination of the furan ring with various carbo- and

• case of 2e) or alcohol (in the case of 2f,g) solution for 1–3 h (ratio of acrylate/CH-acid/AcOK = 1:1:1.5) with a yield of 43–64% (Scheme 7). The structures of the obtained condensed furans 3–7 were characterized by a set of physicochemical methods, including X-ray diffraction analysis. Analysis of the

• frequency values (1725–1731 cm−1). This observation may be due to the position of the ester fragment relative to the heterocyclic system. The analysis of the results of X-ray diffraction analysis shows that the torsion angle C(10)–C(3)–C(16)–O(17) of methyl esters 5a and 6c is −0.8(2), and 5(2)°, and of

Molecular diversity of the reactions of MBH carbonates of isatins and various nucleophiles

• Zi-Ying Xiao,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2025, 21, 286–295, doi:10.3762/bjoc.21.21

• yields. The single crystal structure of the compound 6e was determined by X-ray diffraction (Figure 3). The similar reaction of more nucleophilic tri(tert-butyl)phosphine and MBH carbonate of isatin resulted in a mixture of products. After carefully screening the reaction conditions, we found that DABCO

• triene derivatives can be prepared under relative mild reaction conditions with good steric selectivity. The single crystal structures of compounds 7a and 8a were successfully determined by X-ray diffraction method (Figure 4 and Figure 5). From the crystal structures, it can be found that the compound 7a

Synthesis and characterizations of highly luminescent 5-isopropoxybenzo[rst]pentaphene

• Islam S. Marae,
• Jingyun Tan,
• Rengo Yoshioka,
• Zakaria Ziadi,
• Eugene Khaskin,
• Serhii Vasylevskyi,
• Ryota Kabe,
• Xiushang Xu and
• Akimitsu Narita

Beilstein J. Org. Chem. 2025, 21, 270–276, doi:10.3762/bjoc.21.19

• -0495, Japan X-ray diffraction facility, Department of Chemistry, 100 E. 24th Street, The University of Texas at Austin, Austin, TX 78712, USA 10.3762/bjoc.21.19 Abstract A benzo[rst]pentaphene (BPP) substituted by an isopropoxy group (BPP-OiPr) was synthesized in a facile manner. Its photophysical

• ferric chloride (FeCl3) gave BPP-dione 4 in 70% yield. The chemical structures of BPP-OiPr 3 and BPP-dione 4 were characterized by 1H and 13C NMR spectroscopy as well as mass spectrometry (see Supporting Information File 1, Figures S8–S11). A single crystal of BPP-OiPr 3 suitable for X-ray diffraction

• analysis was obtained by slow evaporation of a diethyl ether/n-hexane solution, enabling its unambiguous structural determination by single-crystal X-ray diffraction (Figure 1). The planar BPP core and the isopropyloxy group on the zigzag edge are clearly visualized (Figure 1a and b). In a unit cell

Synthesis, characterization, and photophysical properties of novel 9‑phenyl-9-phosphafluorene oxide derivatives

• Shuxian Qiu,
• Duan Dong,
• Jiahui Li,
• Huiting Wen,
• Jinpeng Li,
• Yu Yang,
• Shengxian Zhai and
• Xingyuan Gao

Beilstein J. Org. Chem. 2024, 20, 3299–3305, doi:10.3762/bjoc.20.274

• HRMS spectrometry were in full agreement with the expected structures, and single-crystal X-ray diffraction analysis was conducted to confirm the structure of compound 7-H. Moreover, the photophysical properties of these PhFlOP derivatives were determined by UV–vis absorption and photoluminescence

• simple. The structure of 7-H was confirmed by single-crystal X-ray diffraction. Furthermore, UV–vis absorption and PL studies were carried out to explore the photophysical properties of these PhFlOP derivatives. Investigations for further applications of the PhFlOP-based emitters 7 are still ongoing. An