Synthesis of an aza[5]helicene-incorporated macrocyclic heteroarene via oxidation of an o-phenylene-pyrrole-thiophene icosamer

• Yusuke Matsuo,
• Aoi Nakagawa,
• Shu Seki and
• Takayuki Tanaka

Beilstein J. Org. Chem. 2025, 21, 1561–1567, doi:10.3762/bjoc.21.119

• for NHs are omitted for clarity. 1H NMR spectra of 5 in DMSO-d6 (a) at room temperature and (b) at 100 °C. (a) X-ray crystal structure of 5; (left) top view, (right) side view. Thermal ellipsoids are scaled to 50% probability level. Solvent molecules and hydrogen atoms except for NHs are omitted for

• heteroarene 5. Supporting Information Supporting Information File 14: Experimental procedures, characterization data of all products, copies of 1H and 13C NMR spectra, optical data, and DFT calculation results. Supporting Information File 15: Crystallographic Information File for compound 4. Supporting

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

• -substituted aromatic group, we have observed atropoisomerism (Figure 2) what is manifested by the appearance of a second set of signals in their NMR spectra. As the previously studied similar structures (Y = N–R) [22], products 5b and 5d (Y = O) were formed through the addition of a dipole molecule, resulting

Azide–alkyne cycloaddition (click) reaction in biomass-derived solvent Cyrene^TM under one-pot conditions

• Zoltán Medgyesi and
• László T. Mika

Beilstein J. Org. Chem. 2025, 21, 1544–1551, doi:10.3762/bjoc.21.117

• Supporting Information File 1. 1H, 13C, and 19F NMR spectra were collected on a Bruker Avance 300 MHz or Bruker Avance-III 500 MHz instrument and processed by MestReNova v. 14.3.1-31739 (2022) MestreLab Research S. L. GC analyses were performed on an HP 5890 N Series II instrument with Restek RTX®-50

General method for the synthesis of enaminones via photocatalysis

• Paula Pérez-Ramos,
• Raquel G. Soengas and
• Humberto Rodríguez-Solla

Beilstein J. Org. Chem. 2025, 21, 1535–1543, doi:10.3762/bjoc.21.116

• : Additional optimization details, mechanistic studies, experimental details, characterization data and NMR spectra for enaminones 9. Acknowledgements We would like to thank Prof. Jose Manuel Costa-Fernández for his help with the spectroscopic studies. Funding This work has received financial support from MCI

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

• initial ethyl esters were observed in the NMR spectra of the reaction mixtures. Remarkably, ethyl 2-bromopropanoate (4d) reacted less successfully in the transesterification and the yield of methyl ester 5d within 2 h was 66%, even when the catalyst loading was increased to 5 wt %. The transesterification

• 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

• contained thioaminals 9, which underwent a slow isomerization in CDCl3 solution. Notably, in the case of products 9k and 10k, bearing a Ph group at N(1), after a successful chromatographic separation, the less stable 9k underwent isomerization in CDCl3 solution (at rt) and no registration of NMR spectra of

• observed in the 1H NMR spectra registered for crude reaction mixtures (Table 1). The mechanism of the studied reactions deserves a brief comment and should help to clarify whether the formation of 9 and 10 results from the ambident reactivity of 5-mercapto-1H-tetrazoles, suggested in some earlier

• II and they are uncorrected. NMR spectra were taken with a Bruker AVIII spectrometer (1H NMR (600 MHz); 13C NMR (151 MHz); chemical shifts are relative to residual undeuterated solvent peaks (CDCl3: 1H NMR δ = 7.25, 13C NMR δ = 77.00). Elemental analyses were obtained with a Vario EL III (Elementar

Microwave-enhanced additive-free C–H amination of benzoxazoles catalysed by supported copper

• Andrei Paraschiv,
• Valentina Maruzzo,
• Filippo Pettazzi,
• Stefano Magliocco,
• Paolo Inaudi,
• Daria Brambilla,
• Gloria Berlier,
• Giancarlo Cravotto and
• Katia Martina

Beilstein J. Org. Chem. 2025, 21, 1462–1476, doi:10.3762/bjoc.21.108

• benzoxazole with piperidine. Efficacy of silica-supported Cu(I) and Cu(II) in promoting the C2-amination of benzoxazole with piperidine. Copper-supported catalysts. Supporting Information Supporting Information File 24: Experimental procedures, compound characterization data, and copies of NMR spectra

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

• slightly preferred at room temperature with approximately a 3:2 ratio of figure-eight and bathtub conformations. We have also estimated the activation barriers of the interconversion of 3 and 5 between the figure-eight and bathtub conformations by measuring VT 1H NMR spectra in toluene-d8 because the

• beneficial for the development of advanced materials. Synthesis and structures of CBBC 1. X-ray crystal structures of (a) 3, (b) 4, and (c) 5 with thermal ellipsoids at 50% probability; all hydrogen atoms are omitted for clarity. VT 1H NMR spectra of 5 in CD2Cl2 at (a) 298 K, (b) 243 K, and (c) 203 K. Blue

Tautomerism and switching in 7-hydroxy-8-(azophenyl)quinoline and similar compounds

• Lidia Zaharieva,
• Vera Deneva,
• Fadhil S. Kamounah,
• Nikolay Vassilev,
• Ivan Angelov,
• Michael Pittelkow and
• Liudmil Antonov

Beilstein J. Org. Chem. 2025, 21, 1404–1421, doi:10.3762/bjoc.21.105

• makes possible to analyze the tautomerism in 1 as a function of (E+KE) and KK. The NMR spectra of 1 in acetonitrile-d3 are in agreement with the above analysis of tautomeric equilibration based on theoretical calculations and UV spectra. At room temperature the proton signals are very broad and

• precoated TLC plates (0.2 mm thick). The identity of all compounds was confirmed employing various spectroscopic techniques including NMR and HRMS–ESI high-resolution mass spectrometry. The 1H and 13C NMR spectra were recorded in CDCl3 or DMSO-d6 at 25 °C on a Bruker Ultrashield Plus 500 spectrometer using

• multiplicity in the 1H NMR spectra, the following abbreviations were used: s = singlet, br s = broad singlet, d = doublet, t = triplet, dt = double triplet, dd = doublet of doublets, m = multiplet. The HRMS spectra were recorded on a Dionex Acclaim RSLC 120 C18 2.2 mm 120 Å 2.1 × 50 mm column maintained at 40

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

• larger or even commercial scale. The structures of compounds 3 were confirmed by 1H and 13C NMR spectroscopy and high-resolution mass spectrometry. The 1H NMR spectra are characterized by signals from protons of the aromatic rings in the range of 8.08–7.32 ppm, singlets for the proton at the C-3 position

• of the 2,3-dihydro-1,2-thiazole ring in the range of 6.44–6.06 ppm, and multiplets corresponding to the morpholine fragment in the range of 3.80–2.89 ppm or protons of residues of other amino groups in the range of 3.51–1.31 ppm. In the 13C NMR spectra, characteristic signals of the C-4 atom of the

N-Salicyl-amino acid derivatives with antiparasitic activity from Pseudomonas sp. UIAU-6B

• Joy E. Rajakulendran,
• Emmanuel Tope Oluwabusola,
• Michela Cerone,
• Terry K. Smith,
• Olusoji O. Adebisi,
• Adefolalu Adedotun,
• Gagan Preet,
• Sylvia Soldatou,
• Hai Deng,
• Rainer Ebel and
• Marcel Jaspars

Beilstein J. Org. Chem. 2025, 21, 1388–1396, doi:10.3762/bjoc.21.103

• unsaturation, calcd. for C11H12NO5, 238.0721) of 1 was established from negative mode high-resolution electrospray ionisation (HRESI) mass spectrum data which showed a deprotonated molecular ion, [M − H]−1 at m/z 238.0723. The complete analysis of 1D and 2D NMR spectra (see Table 1 and Supporting Information

• , 333.1557) with 9 degrees of unsaturation based on positive mode HRESIMS data which indicated a protonated molecular ion, [M + H]+ at m/z 333.1556 (see Supporting Information File 1, Figure S6). Analysis of 1D and 2D NMR spectra (see Table 1 and Supporting Information File 1, Figures S7–S9) of 2 revealed

• NMR spectra were recorded on a Bruker AVANCE III spectrometer with a Prodigy liquid nitrogen cryoprobe at 600 MHz. Samples were analysed in both positive and negative ion-modes electrospray ionisation using an MS system (Bruker MAXIS II equipped with a Quadrupole-Time-of-Flight mass analyzer) coupled

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

Optimized synthesis of aroyl-S,N-ketene acetals by omission of solubilizing alcohol cosolvents

• Julius Krenzer and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2025, 21, 1201–1206, doi:10.3762/bjoc.21.97

• condensation synthesis of aroyl-S,N-ketene acetals 1 under standard (A)a and modified conditions Bb and Cc. Supporting Information Supporting Information File 6: Experimental details of the synthesis and analytical data of compounds 1 and 3, 1H and 13C NMR spectra of compounds 1 and 3. Acknowledgements We

Synthesis of β-ketophosphonates through aerobic copper(II)-mediated phosphorylation of enol acetates

• Alexander S. Budnikov,
• Igor B. Krylov,
• Fedor K. Monin,
• Valentina M. Merkulova,
• Alexey I. Ilovaisky,
• Liu Yan,
• Bing Yu and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2025, 21, 1192–1200, doi:10.3762/bjoc.21.96

• . Experimental General: In all experiments rt stands for 22–25 °C. 1H and 13C NMR spectra were recorded on Bruker AVANCE II 300, Bruker Fourier 300HD (300.13 MHz for 1H, 75.47 MHz for 13C and 121.49 MHz for 31P, respectively), and Bruker AVANCE II 600 (600.13 MHz for 1H, 150.92 MHz for 13C, 242.93 MHz for 31P

• phosphorylation of enol acetates. Optimization of reaction conditions for the synthesis of β-ketophosphonate 3a from enol acetate 1a and diisopropyl H-phosphonate (2a)a. Supporting Information Supporting Information File 4: Experimental details, compound characterization data, and NMR spectra. Funding This work

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

• % yield. Alcohol products, [4.3.3]_CH2OH and [3.3.3]_CH2OH, were then tested in acidic conditions using anhydrous FeCl3 as a Lewis acid. After the reactions, the alcohol proton signals at 1.54–1.58 ppm disappeared in the 1H NMR spectra, and aliphatic carbon ones at 63.1–63.2 ppm were largely up-field

• -shifted to ca. 34 ppm in the 13C NMR spectra due to conversion into methylene groups (Figure 2b and Figures S315 and S316 in Supporting Information File 1). However, all 1H NMR signals were broad, and gel permeation chromatography (GPC) charts indicated broad patterns due to multiple products with varying

• electrophilic functionalization. a) Synthesis of methylene-alternating copolymers of fully π-fused propellanes. DCE, 1,2-dichloroethane. b) 1H NMR (500 MHz, top) and 13C (126 MHz, bottom) NMR spectra of [4.3.3]_CH2OH and [4.3.3]_linear in CDCl3 at room temperature. Gas adsorption (filled circles) and desorption

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

• -aromatization. Optimization of IMDA and re-aromatization reactions for the preparation of 8a. Supporting Information Supporting Information File 50: General reaction procedures, compound characterization data, and copies of NMR spectra. Conflict of Interest The authors declare no competing financial interest.

Investigations of amination reactions on an antimalarial 1,2,4-triazolo[4,3-a]pyrazine scaffold

• Henry S. T. Smith,
• Ben Giuliani,
• Kanchana Wijesekera,
• Kah Yean Lum,
• Sandra Duffy,
• Aaron Lock,
• Jonathan M. White,
• Vicky M. Avery and
• Rohan A. Davis

Beilstein J. Org. Chem. 2025, 21, 1126–1134, doi:10.3762/bjoc.21.90

• General experimental Melting points were measured using a Cole-Parmer (Chicago, IL, USA) melting point apparatus and were uncorrected. UV spectra were recorded using an Ocean Optics (USB-ISS-UV/VIS) spectrophotometer. NMR spectra were recorded at 25 °C on a Bruker (Billerica, MA, USA) AVANCE III™ HD 500

• cell line HEK293. Supporting Information Supporting Information File 44: Complete experimental methods, crystallographic data for 2, 7, 10 and 15, characterisation data and 1D/2D NMR spectra (1H, 13C, COSY, HSQC and HMBC) for 2–15. Acknowledgements The authors wish to thank and acknowledge the

A versatile route towards 6-arylpipecolic acids

• Erich Gebel,
• Cornelia Göcke,
• Carolin Gruner and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 1104–1115, doi:10.3762/bjoc.21.88

• after workup. Purifying the bromide 2 via column chromatography was deemed unnecessary after comparing the NMR spectra of the worked-up and the purified product. While the worked-up product 2 exhibited only slight differences in impurities, the yield was significantly reduced due to purification by

• favourable chair conformation with the aryl substituent and the methyl ester in equatorial positions (Figure 3), providing further evidence for conformational restraints (pseudoallyl strain) enforced by the formyl group. This behaviour is observable in all NMR spectra of the compound array of the reduction

• ). Analysing the 1H NMR spectra of reduction product (2R,6S)-13 reveals a very similar pattern to the previously discussed Suzuki–Miyaura product (2R,6S)-9 with one significant distinction. The signals of both protons H2 and H6 of the first conformer (2R,6S)-13I in comparison to the second one (2R,6S)-13II are

Supramolecular assembly of hypervalent iodine macrocycles and alkali metals

• Krishna Pandey,
• Lucas X. Orton,
• Grayson Venus,
• Waseem A. Hussain,
• Toby Woods,
• Lichang Wang and
• Kyle N. Plunkett

Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87

• NaBArF24. Supporting Information Supporting Information File 29: Detailed experimental procedures, NMR spectra, and X-ray crystallography details. Supporting Information File 30: Crystallographic Information Files for 1/LiBArF20 and 1/NaBArF24. Funding We thank the National Science Foundation (#2003654

Salen–scandium(III) complex-catalyzed asymmetric (3 + 2) annulation of aziridines and aldehydes

• Linqiang Wang and
• Jiaxi Xu

Beilstein J. Org. Chem. 2025, 21, 1087–1094, doi:10.3762/bjoc.21.86

• mechanism. Gram-scale synthesis. Optimization of reaction conditions.a Supporting Information Supporting Information File 24: Analytic data and copies of 1H and 13C NMR spectra of compounds 1 and 3, copies of HRMS spectra of unknown compound 3 and copies of HLPC profiles of compounds 3. Funding This

Biobased carbon dots as photoreductants – an investigation by using triarylsulfonium salts

• Valentina Benazzi,
• Arianna Bini,
• Ilaria Bertuol,
• Mariangela Novello,
• Federica Baldi,
• Matteo Hoch,
• Alvise Perosa and
• Stefano Protti

Beilstein J. Org. Chem. 2025, 21, 1024–1030, doi:10.3762/bjoc.21.84

• voltammetry of triarylsulfonium salts and NMR spectra. Funding Fondazione Cariplo (Photo and Mechano-Chemistry for the Upgrading of Agro- and Sea-food Waste to advanced polymers and nanocarbon materials, CUBWAM, project 2021–0751).

Pd-Catalyzed asymmetric allylic amination with isatin using a P,olefin-type chiral ligand with C–N bond axial chirality

• Natsume Akimoto,
• Kaho Takaya,
• Yoshio Kasashima,
• Kohei Watanabe,
• Yasushi Yoshida and
• Takashi Mino

Beilstein J. Org. Chem. 2025, 21, 1018–1023, doi:10.3762/bjoc.21.83

• allylic amination of acetate 12 with isatin (11a).a Supporting Information Data of thermal racemization of 7, DFT calculations for investigating racemization mechanism of 7, general methods and materials, experimental procedures and characterization data, 1H, 13C and 31P NMR spectra for 9 and 10, 1H, 13C

• and 31P NMR spectra and HPLC charts for (±)-7, (+)-7 and (–)-7, 1H and 13C NMR spectra and HPLC charts for (S)-13a–k (except (S)-13e) and (S)-16. Supporting Information File 18: Experimental section and compounds characterization. Funding This work was supported by a Grant-in-Aid for Scientific

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

• request/cif. Supporting Information File 6: ORTEP diagram of compound 31, synthetic procedures, IR, 1H, 13C, 19F and 2D NMR spectra of compounds 2, 5, 6, 24–28 and 30–32. Supporting Information File 7: Crystallographic information file of compound 31. Supporting Information File 8: Checkcif file for

Harnessing tethered nitreniums for diastereoselective amino-sulfonoxylation of alkenes

• Shyam Sathyamoorthi,
• Appasaheb K. Nirpal,
• Dnyaneshwar A. Gorve and
• Steven P. Kelley

Beilstein J. Org. Chem. 2025, 21, 947–954, doi:10.3762/bjoc.21.78

• functional group compatibility. Supporting Information Supporting Information File 2: Additional experimental details including reaction procedures, X-ray crystallographic data, and NMR spectra of synthesized compounds. Acknowledgements Justin Douglas and Sarah Neuenswander (KU NMR Lab) are acknowledged

Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts

• Katy Medrano-Uribe,
• Jorge Humbrías-Martín and
• Luca Dell’Amico

Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76

• NMR spectra. Acknowledgements L. D. and K. M. U. thank Dr. Ilaria Fortunati for her technical support during the lifetime measurements. Funding The financial support of the authors is provided by the Ministero dell'Università e della Ricerca (MUR, C93C22007660006, K.M.U), Fondazione Cariparo