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

• , 13C NMR spectroscopy and high-resolution MS. 1H NMR spectra of obtained products contain characteristic signals of the protons of the methyl group in the region δ 1.72–2.16 ppm and proton of pyranone fragment in the region δ 5.98–6.62 ppm. Besides that, the key structures of synthesized products were

• Supporting Information File 2: General information, characterization data, NMR spectra and crystallographic data of synthesized compounds. Acknowledgements Crystal structure determination was performed in the Department of Structural Studies of Zelinsky Institute of Organic Chemistry, Moscow.

Asymmetric synthesis of β-amino cyanoesters with contiguous tetrasubstituted carbon centers by halogen-bonding catalysis with chiral halonium salt

• Yasushi Yoshida,
• Maho Aono,
• Takashi Mino and
• Masami Sakamoto

Beilstein J. Org. Chem. 2025, 21, 547–555, doi:10.3762/bjoc.21.43

• for the construction of contiguous tetrasubstituted carbon centers via the Mannich reaction and this work. Plausible reaction mechanism. Catalyst screening for the asymmetric Mannich reaction. All yields were determined by 1H NMR spectroscopy using 1,3,5-trimethoxybenzene as an internal standard. N

• -Protecting group optimization for the asymmetric Mannich reaction. All yields were determined by 1H NMR spectroscopy using 1,3,5-trimethoxybenzene as an internal standard. aReaction conducted for 24 h. Catalyst screening using 7b as a substrate. All yields were determined by 1H NMR spectroscopy using 1,3,5

• : Experimental procedures, characterization data, NMR spectra, and HPLC chromatograms. Funding This research was funded by an IAAR Research Support Program (Chiba Halogen Science: Halogen-Linkage of Molecular Functions); Chiba University Open Recruitment for International Exchange Program, Chiba University

Binding of tryptophan and tryptophan-containing peptides in water by a glucose naphtho crown ether

• Gianpaolo Gallo and
• Bartosz Lewandowski

Beilstein J. Org. Chem. 2025, 21, 541–546, doi:10.3762/bjoc.21.42

• tryptophan and Trp-containing peptides by 1 we performed NMR measurements on the 1:1 host–guest complexes in D2O. Upon binding of tryptophan by 1 a significant upfield shift of the aromatic protons and a slightly smaller shift, also upfield, of the α and β-Trp protons was observed (Figure 3). The aromatic

• naphthalene fluorescence during the titration. 1H NMR (D2O) stacked plot: top – H-Trp-OH; middle – H-Trp-OH + receptor 1 (1:1); bottom – receptor 1; the dotted black lines indicate shifts of the proton signals upon complex formation. 1H NMR (D2O) stacked plot: top – H-TrpAlaAla-NH2 (2); middle – 2 + receptor

• fluorescence and NMR experiments. Acknowledgements We would like to thank Prof. Wennemers for her continuous support and for providing access to the infrastructure necessary to carry out the research described herein.

Vinylogous functionalization of 4-alkylidene-5-aminopyrazoles with methyl trifluoropyruvates

• Judit Hostalet-Romero,
• Laura Carceller-Ferrer,
• Gonzalo Blay,
• Amparo Sanz-Marco,
• José R. Pedro and
• Carlos Vila

Beilstein J. Org. Chem. 2025, 21, 533–540, doi:10.3762/bjoc.21.41

• dichloroethane, chloroform or ethyl acetate gave lower yields but similar diastereoselectivity. More polar solvents such THF and CH3CN afforded the corresponding alcohol 5aaa with lower diastereoselectivity. When acetone was used as solvent, product 5aaa was not detected in the 1H NMR of crude reaction mixture

• chromatography. Diastereoisomeric ratio (dr) determined by 1H NMR of the crude reaction mixture. Plausible mechanism and X-ray structure of compound 5aca. Optimization of the reaction conditions.a Supporting Information Supporting Information File 14: Detailed experimental procedures, characterization data, and

• copies of 1H NMR and 13C NMR spectra. Acknowledgements Access to NMR, MS, and X-ray facilities from the Servei Central de Suport a la Investigació Experimental (SCSIE)-UV and the NMR U26 facility of ICTS “NANBIOSIS” is acknowledged. Funding L.C.-F. thanks the Universitat de València for a predoctoral

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

• free of charge from the Cambridge Crystallographic Data Centre (CCDC) via https://www.ccdc.cam.ac.uk/structures under reference number CCDC 2400694 for Boc-ᴅ-Phe(4-NHMe)-OMe (7). Supporting Information File 12: Experimental section, NMR spectra and cellular proliferation assays. Acknowledgements We

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

• photochemical reaction. Its structure was elucidated by NMR spectroscopy and single crystal X-ray diffractometry. The latter revealed no π–π interaction between neighboring ANTH cores. A combination of high photoluminescence quantum yield (PLQY) of 0.85 for 9,10-ANTH(BnF)2, its significantly improved

• used for the perfluorobenzylation of PERY were used [22]. 9,10-ANTH(Br)2 and BnFI were dissolved and heated to 160 °C in PhCN in the presence of either Cu powder (22 h) or Na2S2O3 (4 h). According to the 1H NMR spectra of the filtered product mixtures, the reaction with Cu showed poor conversion, but

• of the solid products practically impossible. When NMP was used as the solvent, the reaction of 9,10-ANTH(Br)2, BnFI, and Na2S2O3 did not result in the formation of 9,10-ANTH(BnF)2 but mainly in the formation of 9-Br-10-BnF-ANTH (39%, determined by NMR). Overall, the methods described above all

Synthesis of the aggregation pheromone of Tribolium castaneum

• Biyu An,
• Xueyang Wang,
• Ao Jiao,
• Qinghua Bian and
• Jiangchun Zhong

Beilstein J. Org. Chem. 2025, 21, 510–514, doi:10.3762/bjoc.21.38

• of (R)-2-methyloxirane ((R)-2) with allylmagnesium bromide (3) catalyzed by CuI produced a mixture of (R)-hex-5-en-2-ol ((R)-4) and (S)-2-methylpent-4-en-1-ol ((S)-4’) (ratio 8:1, determined by 1H NMR spectroscopy) [25][26]. The primary alcohol (S)-4’ could be easily removed by a selective TEMPO

• oxidation. The optical purity of the chiral secondary alcohol (R)-4 was more than 99% ee, determined by 1H NMR spectrum of its Mosher ester [27][28]. The subsequent tosylation with p-tosyl chloride gave (R)-hex-5-en-2-yl 4-methylbenzenesulfonate ((R)-5) in 88% yield [29]. The reaction of (R)-5 with the

• ]. (4R,8R)-4,8-Dimethyldecanal ((4R,8R)-1) was obtained from chiral terminal olefine (5R,9R)-12 through the oxidation with RuCl3 and NaIO4 [36], and its specific rotation and NMR spectrum matched with the reference [20]. Moreover, using the similar procedure for (4R,8R)-1, the other three constituents of

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

• purification, the 1H NMR of Cl2B showed 6% of an impurity, possibly the anti-isomer. Further purification of Cl2B reduced the impurity content to less than 3%. Topochemical photocycloaddition Upon examining the crystal structure of our first sample of Cl2B, Cl2B (A), we observed that the compound had undergone

• shielding from light, and unavoidable light exposure during crystal selection, and the X-ray measurement itself. As an additional test, the compounds were prepared as NMR samples in DMSO-d6 and irradiated with 405 nm LED. Irradiation in the solution phase did not result in any dimerization; the respective

• ¹H NMR spectra remained unchanged compared to the neat compounds (Figures S1, S3, and S5, Supporting Information File 1), confirming that the reaction occurs selectively in the solid state. Cl2B was also irradiated in DCM with the same 405 nm LEDs, in a quartz fluorescence cuvette. A UV–vis spectrum

Synthesis of N-acetyl diazocine derivatives via cross-coupling reaction

• Thomas Brandt,
• Pascal Lentes,
• Jeremy Rudtke,
• Michael Hösgen,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2025, 21, 490–499, doi:10.3762/bjoc.21.36

• /data_request/cif. Cambridge CB2 1EZ, UK; fax: +44 1223 336033. Supporting Information File 14: Synthetic procedures, UV–vis and NMR switching experiments, copies of UV–vis and NMR spectra, and X-ray crystallographic data. Funding The authors thankfully acknowledge financial support by the Deutsche

Synthesis of electrophile-tethered preQ₁ analogs for covalent attachment to preQ₁ RNA

• Laurin Flemmich and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35

• (16) see Supporting Information File 1. Syntheses of haloalkyl- and mesyloxyalkyl-modified preQ1 as and DPQ1 ligands. Supporting Information Supporting Information File 12: Experimental part, HPLC analysis of preQ1 and NMR spectra. Acknowledgements We thank Clemens Eichler (University of Innsbruck

• ) for synthetic contributions. Funding This work was funded in part by the Austrian Science Fund FWF [P31691, F8011-B] and the Austrian Research Promotion Agency FFG [West Austrian Bio NMR 858017].

Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction

• James Guevara-Pulido,
• Fernando González-Pérez,
• José M. Andrés and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34

• ] using 20 mol % of catalyst A and 20 mol % of p-nitrobenzoic acid (PNBA) as co-catalyst in different solvents at room temperature. The results obtained are summarized in Scheme 3 and Table 1. The progress of the reaction was monitored using thin-layer chromatography (TLC) and 1H NMR analysis of the

• substituents present in the starting Michael adducts. Furthermore, it has been observed that the enantioselectivity of Michael adducts decreases with time in the presence of a catalyst derived from diarylprolinol. Experimental General Information 1H NMR (400 or 500 MHz) and 13C NMR (100 MHz) spectra were

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• zinc cations to align 1.1 through the formation of hydrogen-bonded coordination complexes. Thus, when a single crystal of the [Zn(bpe)2(H2O)4](NO3)2·8/3H2O·2/3bpe complex was exposed to UV irradiation (dark blue phosphor lamps, λ = 350 nm) for 25 h, only 46% conversion to 1.2 was observed via 1H NMR

• agent 2.2 in a sub-stoichiometric fashion (20 mol %). However, even upon prolonged exposure, the yield of 2.3 did not exceed 20% (by 1H NMR spectroscopy). To achieve turnover, the photoreacted solid was subjected to a second grinding and exposed again to UV irradiation for an additional 16 h, which

• resulted in 40% yield. Alternating grinding and irradiation, the authors managed to obtain quantitative conversion of 2.1 to 2.3. Overall, in this work, mechanochemistry worked akin to agitation provided by stirring or heating in solution. In fact, 1H NMR spectroscopy, XRD and DFT analyses showed that

Electrochemical synthesis of cyclic biaryl λ³-bromanes from 2,2’-dibromobiphenyls

• Andrejs Savkins and
• Igors Sokolovs

Beilstein J. Org. Chem. 2025, 21, 451–457, doi:10.3762/bjoc.21.32

• electrode, Pt foil as counter electrode, 0.1 M tetrabutylammonium tetrafluoroborate (TBA-BF4) in HFIP electrolyte and 2 F passed charge at a current density of 10 mA·cm−2) afforded the desired Br(III) product 1a in poor 14% NMR yield (Table 1, entry 1). The cyclic diarylbromonium salt 1a was isolated by

• 4a and 6, parameters that influence the jp vs v0.5 slope, are similar. On the other hand, anodic oxidation of 4a under optimized conditions (entry 6, Table 1) using 1 F returned only 35% of 1a (NMR yield), whereas passing 2 F charge delivered 1a in 60% yield. The latter data provides an evidence that

• hypobromite D. The latter decomposes into bromide and hexafluoroacetone, with the latter observed by 19F NMR [25]. Assuming that intermediate B is sufficiently stable to leave the diffusion layer and undergoes disproportionation to the species C in the bulk electrolyte provides a reasonable explanation for

New tandem Ugi/intramolecular Diels–Alder reaction based on vinylfuran and 1,3-butadienylfuran derivatives

• Yuriy I. Horak,
• Roman Z. Lytvyn,
• Andrii R. Vakhula,
• Yuriy V. Homza,
• Nazariy T. Pokhodylo and
• Mykola D. Obushak

Beilstein J. Org. Chem. 2025, 21, 444–450, doi:10.3762/bjoc.21.31

• products were identified via NMR as 4,4a,5,6,7,7a-hexahydro-3aH-furo[2,3-f]isoindoles. The structures of compounds 5 were confirmed by NMR spectroscopy data (for details and discussion see Supporting Information File 1). The NMR data for the obtained furoindole skeleton signals and spin-coupling constants

• these compounds were confirmed by NMR spectroscopy (see Supporting Information File 1). Conclusion In summary, we showed the practical usage of 3-(furan-2-yl)acrylaldehyde in the four-component Ugi reaction with the prospect of further intramolecular [4 + 2] cycloaddition of the Ugi reaction product. We

• , compound characterizations, and NMR spectra. Funding The authors are thankful to the Ministry of Education and Science of Ukraine and Simons Foundation (Award Numbers: 1290588) for financial support.

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• catalysis [229]. Methods to study the structural detail of catalysis in frameworks remain limited, and crucial techniques like solution-phase NMR are rarely useful [22]. Enzyme encapsulation [230], and electro- and photocatalysis are known [228], and chiral and low symmetry MOFs are an exciting avenue

Identification and removal of a cryptic impurity in pomalidomide-PEG based PROTAC

• Bingnan Wang,
• Yong Lu and
• Chuo Chen

Beilstein J. Org. Chem. 2025, 21, 407–411, doi:10.3762/bjoc.21.28

• pomalidomide or its close analogs, indicating that a side reaction unrelated to the SNAr of the fluoride has occurred. 1H NMR and MS analyses suggested that phthalimide 5 was the byproduct formed through this series of transformations. Supporting this hypothesis, analysis of the reaction intermediates

• reaction was concentration dependent, giving various amounts of 6 under otherwise the same reaction conditions. For example, at 10–30 mM wherein most of the pilot studies were conducted, the ratio of 3 and 6 could be as low as ≈1:50 by 1H NMR and ≈1:10 by MS analysis. Under these conditions, the formation

• <1% impurity based on 1H NMR and MS analysis. The mechanism by which glutarimide displacement competes with SNAr merits some discussion. Thalidomide is well known for its configurational instability and racemizes rapidly [8]. However, equally important but much less appreciated is its hydrolytic

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• investigated the role of the C-2 protecting group in Schmidt’s trichloroacetimidate glycosylation with donor 60 which showed excellent yield along with the formation of the 1,2-trans glycoside only. They proposed the mechanism with the help of NMR spectroscopy and the studies revealed that the N

• supported by NMR data showing the formation of the respective intermediates. Previously, this stabilisation of a similar α-glycosyl intermediate had been successfully implemented by Crich et al. leading to high β-selectivity in challenging mannose and rhamnose moieties [37]. The moderate yield and β

• the formation of 1,2-trans stereodirected glycosyl products 77 when the donor was suitably activated using BSP and Tf2O [139]. The role of the 2,2-dimethyltrimethylene (DMTM) phosphate group at the participating C-2 protection was analysed wherein the NMR studies showed no isolation of the

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

• 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

• 1,2-benzoquinone and o-chloroanil, respectively [1][25]. The structures of compounds 7 and 8 obtained by methods A and B were confirmed by 1H NMR, IR spectroscopy and mass spectrometry (Supporting Information File 2). A distinctive feature of the 1H NMR spectra of 7 in CDCl3 is the signal of the

• tropolone ring proton, which appears at 6.9 ppm. A characteristic specificity of the 1H NMR spectra of compounds 7 and 8 is the presence of signals of hydroxy group protons forming a strong hydrogen bond with the indoline nitrogen atom, which closes the six-membered chelate cycle. These signals are observed

Synthesis, characterization, antimicrobial, cytotoxic and carbonic anhydrase inhibition activities of multifunctional pyrazolo-1,2-benzothiazine acetamides

• Ayesha Saeed,
• Shahana Ehsan,
• Muhammad Zia-ur-Rehman,
• Erin M. Marshall,
• Sandra Loesgen,
• Abdus Saleem,
• Simone Giovannuzzi and
• Claudiu T. Supuran

Beilstein J. Org. Chem. 2025, 21, 348–357, doi:10.3762/bjoc.21.25

• and 13C NMR spectroscopy. All compounds were tested against five human microbial strains including three different strains of Staphylococcus aureus (ATCC 25923, ATCC BAA-41, and ATCC BAA-44), Escherichia coli (ATCC 8739), and Candida albicans (ATCC 90027) to evaluate their antibiotic potential. The

• oxygen atom [50]. Preferential N-alkylation (over O-alkylation) of 1,2-benzothiazine scaffolds has also been carried out by Ahmad and co-workers in 2014 and Szczęśniak-Sięga and companions in 2018 [37][51]. Structure elucidation of all the synthesized derivatives was carried out using 1H, 13C NMR, and

• FTIR spectroscopy as well as HRMS. Table 1 shows the different substituents (R groups) for the synthesized compounds 7a–n. The 1H NMR spectra of compounds 7a–h showed one distinct singlet at 4.92 to 5.12 ppm for the two protons of one methylene group (Figure 2b’), a singlet for the NH proton in the

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

• -dihydronaphtho[1,2-b]furan-3-carboxylate 4a,b with a total yield of up to 73% (ratio 3a/4a = 2:1; 3b/4b = 2:1, according to 1H NMR spectroscopy) (Scheme 4). Using preparative chromatography, the mixture was separated into individual substances. In turn, alkyl 7,7-dimethyl-4,9-dioxo-6,7,8,9-tetrahydro-4H-furo[3,2

• data, they luminesce in DMSO solution when irradiated with light at wavelengths of 352 and 283 nm. Compounds 7a–f are capable of existing as lactim–lactam tautomers due to the presence of an amide fragment in their structure (Scheme 7). At the same time, the 1H and 13C NMR spectra of compounds 7a–f

• indicate their individuality. The presence of a broadened signal in the 1H NMR spectra (DMSO-d6) in the region of 12.49–12.84 ppm and a C4 signal in the 13C NMR spectra (DMSO-d6) in the region of 158.1–159.0 ppm does not allow us to unambiguously determine the tautomeric form of compounds 7a–f in solution

Antibiofilm and cytotoxic metabolites from the entomopathogenic fungus Samsoniella aurantia

• Rita Toshe,
• Syeda J. Khalid,
• Blondelle Matio Kemkuignou,
• Esteban Charria-Girón,
• Paul Eckhardt,
• Birthe Sandargo,
• Kunlapat Nuchthien,
• J. Jennifer Luangsa-ard,
• Till Opatz,
• Hedda Schrey,
• Sherif S. Ebada and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 327–339, doi:10.3762/bjoc.21.23

• ]+ (calculated 446.1962). The UV–vis spectrum of 1 (Figure S3, Supporting Information File 1) revealed a prominent absorption peak (λmax) at 434 nm in the visible region reflected by being yellow-colored and suggesting the presence of an extended conjugated π-system in its structure. The 1H NMR and 1H–1H COSY

• that it is a related derivative to two yellow pyridone pigments, farinosones A and B, that were previously reported from Cordyceps farinosa syn. Paecilomyces farinosus [8][9]. A detailed comparison of the 1H and 13C NMR data of 1 and farinosones A/B revealed that instead of a deshielded pyridone

• acid derivative named farinosone D. In addition, five known secondary metabolites were identified based on HRESIMS and detailed 1D/2D NMR spectroscopic analyses along with comparison with the reported literature. The isolated compounds were differentiated into two 2-pyridone derivatives farinosones A

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

• 2390715), 7a (CCDC 2390716) and 8a (CCDC 2390717) have been deposited at the Cambridge Crystallographic Database Center. Supporting Information File 2: Experimental procedures, 1H, 13C NMR, and HRMS spectra for all new compounds. Funding This work was financially supported by the National Natural Science

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

• literature. During our attempt to scale up the preparation of BPP 2 through the "DPEX" reaction, we unexpectedly obtained a 5-isopropoxy-substituted derivative of BPP (BPP-OiPr 3) (Scheme 1), whose structure was proven by NMR, mass spectrometry, and X-ray crystallography. In this work, we optimized the

• 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

• BPP 2 and BPP-OiPr 3. Supporting Information Supporting Information File 114: Experimental and computational details, X-ray crystallography, synthesis and characterization of new compounds, additional PL, mass, and NMR spectra, and theoretical calculations. Acknowledgements We appreciate the help

Three-component reactions of conjugated dienes, CH acids and formaldehyde under diffusion mixing conditions

• Dmitry E. Shybanov,
• Maxim E. Kukushkin,
• Eugene V. Babaev,
• Nikolai V. Zyk and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 262–269, doi:10.3762/bjoc.21.18

• alcohol 2. Its 1H NMR spectrum contained a triplet with a coupling constant of 5.1 Hz at 5.52 ppm and a doublet at 4.30 ppm. In methanol, ethanol and petroleum ether, with an increasing reaction time, a significant amount of product 3 was observed in the 1H NMR spectra of the mixtures, as identified by

• an important role; the presence of the condensation catalyst ʟ-proline accelerated the absorption of formaldehyde vapors by the reaction mixture. Carrying out the same reaction in the absence of a catalyst in CDCl3 and subsequent 1H NMR spectroscopy analysis showed that the mixture contained 42% of

• and 8, the reaction also produced hetero-Diels–Alder reaction adducts 6 and 9. For these, CH–O 1H NMR signals in the region of 4.9–5.4 ppm were characteristic. It is worth noting that the individual isolated compounds 8 and particularly 9 were unstable when stored in solution, and boiling adduct 8 or

Synthesis of disulfides and 3-sulfenylchromones from sodium sulfinates catalyzed by TBAI

• Zhenlei Zhang,
• Ying Wang,
• Xingxing Pan,
• Manqi Zhang,
• Wei Zhao,
• Meng Li and
• Hao Zhang

Beilstein J. Org. Chem. 2025, 21, 253–261, doi:10.3762/bjoc.21.17

• , and copies of NMR spectra. Funding This work was supported by the Talent Project of Fuyang Normal University (No. XJRCXM202232), the College Students Innovative Entrepreneurial Training Plan Program (No. S02310371028), The Natural Science Foundation of Higher Education Institutions in Anhui Province