Electrochemical reduction of unsaturated carbon–carbon bonds via 3d transition-metal catalysis

• Geon Kang,
• Minki Jeon,
• Pooja Kumari Jat,
• Cheoljae Kim and
• Isaac Choi

Beilstein J. Org. Chem. 2026, 22, 955–981, doi:10.3762/bjoc.22.75

• deuterium incorporation occurs exclusively at the vinylic positions of the terminal alkene, with no evidence for internal alkene formation (Scheme 13C). Consequently, these observations indicate that the semireduction pathway proceeds without the involvement of a nickel hydride species, instead favoring a

Palladium-catalyzed benzocyclization reactions of quinoline-2-carboxamides via sequential C–H/N–H functionalization

• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2026, 22, 905–914, doi:10.3762/bjoc.22.71

• for the C–H/N–H functionalization reaction. Supporting Information Supporting Information File 6: Experimental details and copies of 1H and 13C{1H} NMR spectra. Acknowledgements We thank Suzanne Adam, Ph.D, from Edanz (https://jp.edanz.com/ac) for editing a draft of the manuscript. Funding This

Cascade transformation of 2-(diazoacetyl)-2H-azirines to 2-aroyl-3-hydroxy-1H-pyrroles via condensation with aromatic aldehydes

• Timur O. Zanakhov,
• Ekaterina E. Galenko,
• Mikhail S. Novikov and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2026, 22, 897–904, doi:10.3762/bjoc.22.70

• -methoxyphenyl)-2H-azirine 1b with 4-iodobenzaldehyde (2b) turned out to be well crystallized and precipitated from the reaction medium as a solid (Scheme 2). Although it was also unstable, it was possible to record 1H,1H 2D NOESY and 13C NMR spectra, an IR spectrum in KBr as well as to obtain the accurate mass

Unsymmetrical sulfoxides with sterically hindered catechol fragment: synthesis, structure, electrochemical properties, and antiradical activity

• Daria A. Burmistrova,
• Vasiliy A. Fokin,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Maxim V. Arsenyev,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2026, 22, 828–837, doi:10.3762/bjoc.22.65

• catechol moiety were detected. The yields of the target sulfoxides ranged from 42% to 89%. Compounds 3–6 were prepared and characterized as described previously (3, 4, and 6 [23], 5 [42]). The structures of new thioethers 1, 2, 7 and sulfoxides 1a–7a were confirmed by the spectral methods IR-, 1H NMR, 13C

• thioethers (δ 7.11–7.30 ppm) and appears in the range of δ 11.33–11.85 ppm (CDCl₃; see Supporting Information File 1, Section S2). The signal of the second OH proton is also shifted downfield compared to that in the thioethers (δ 5.53–5.58 ppm) and is observed at δ 6.04–6.17 ppm. In the 13C NMR spectra of

Synthesis and structural elucidation of a novel bis-spirooxindole from isatin and ethylenediamine

• Irene Moreno-Gutiérrez,
• Josefa L. López-Martínez,
• Sonia Berenguel-Gómez,
• Irene Torres-García,
• Duane Choquesillo-Lazarte,
• Manuel Muñoz-Dorado,
• Miriam Álvarez-Corral and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2026, 22, 813–820, doi:10.3762/bjoc.22.63

• aromatic pattern of the isatin core. The IR spectrum showed a strong imine C=N band at 1610 cm−1, and the absence of the C-3 carbonyl stretching band confirmed complete condensation. The 13C NMR spectrum revealed multiple sets of closely related signals, consistent with the presence of three C=N

• retained the four-signal pattern of isatin (H4', H5', H6', H7'), slightly shifted by the new structural environment. In the 13C NMR spectrum, the amide carbonyl appeared at δ 176.5 ppm, while a key quaternary carbon at δ 61.0 ppm (C3‘) – formerly the C-3 isatin carbonyl carbon – confirmed the formation of

• , 1021, 739; 1H NMR (600 MHz, DMSO-d6) δ (ppm) 10.83 (bs, 2H, NH), 7.84 (bd, J = 7.7 Hz, 2H, H4’, H4’’), 7.45 (td, J = 7.8, 1.1 Hz, 2H, H6’, H6’’), 7.08 (td, J = 7.7, 0.9 Hz, 2H, H5’,H5’’), 6.94 (bd, J = 7.8 Hz, 2H, H7’,H7’’), 4.45 (s, 4H, =NCH2); 13C NMR (125 MHz, DMSO-d6) δ 164.08 (C), 164.05 (C

Synthetic study of vic-bromination of diarylacetylenes, easy purification and separation

• Akane Togo,
• Hiyono Suzuki,
• Yuto Akai,
• Makoto Matsumoto,
• Yoshinori Suzuma,
• Hidehiko Kodama and
• Kouichi Matsumoto

Beilstein J. Org. Chem. 2026, 22, 795–802, doi:10.3762/bjoc.22.61

• crude product was purified three times with heptane to obtain (E)-1,2-dibromo-1,2-diphenylethylene (E-2a, 132.6 mg, 0.392 mmol, 78% yield) of high-purity. (E)-1,2-Dibromo-1,2-diphenylethylene (E-2a) [4]: White solid. 1H NMR (400 MHz, CDCl3) δ 7.34–7.46 (m, 6H), 7.50–7.57 (m, 4H) ppm; 13C NMR (100 MHz

• CDCl3) δ 118.0, 128.4, 128.9, 129.1, 140.7 ppm; HRMS (ESI) m/z: [M + Na]+ calcd for C14H10Br2Na, 358.9041; found, 358.9028. (Z)-1,2-Dibromo-1,2-diphenylethylene (Z-2a) [7]: Yellow solid. 1H NMR (300 MHz, CDCl3) δ 7.10–7.22 (m, 10H) ppm; 13C NMR (75 MHz, CDCl3) δ 125.7, 128.0, 128.3, 129.8, 139.4 ppm

• of compounds, and copies of 1H and 13C NMR spectra. Acknowledgements We appreciate Kazuki Miyamoto, Junya Kikuzawa and Ryoichi Tomiyama at Kindai University for useful advice and the cooperation related to this paper. We also thank Akiko Kuwabara and Dr. Masafumi Kobayashi at Kanto Denka Kogyo Co

Halogenated azobenzene acrylates: from efficient solution photoswitching to stable solid-state photochromic materials

• Martina Vachtlová,
• Michaela Fecková,
• Vítězslav Zima,
• Jan Podlesný,
• Milan Klikar,
• Oldřich Pytela,
• Patrik Pařík,
• Jakub Opršal,
• Eliška Juhaňáková,
• Veronika Chrtová and
• Filip Bureš

Beilstein J. Org. Chem. 2026, 22, 782–794, doi:10.3762/bjoc.22.60

• calorimetry (DSC), thermogravimetric analysis (TGA), cyclic voltammetry (CV), UV–vis absorption spectroscopy, 1H and 13C NMR, and theoretical DFT calculations were employed. Furthermore, the target compounds are designed for incorporation as photoactive copolymers into the structure of functionalized

Synthesis and biological evaluation of new brassinosteroid analogs with C-22 benzoate function

• María Núñez,
• Camila Escobar,
• Mario Párraga,
• Mauricio Soto,
• Luis Espinoza-Catalán,
• Katy Díaz and
• Andrés F. Olea

Beilstein J. Org. Chem. 2026, 22, 753–762, doi:10.3762/bjoc.22.57

• 7.2 Hz, H-22b), are assigned to carbinolic hydrogens H-22a and H-22b, respectively. In the 13C NMR spectrum, the signals observed at δ = 166.57, 143.31, 129.40, 128.93, 127.65, and 21.52 ppm, are assigned to carbon ArCOO, C-4’, C-2’, C-3’, C-1’, and CH3-Ar of the benzoate group, respectively. All

• dihydroxylation of double bond on C-2 of compounds 23–28, following a described procedure [29], leads to BR analogs 17–22 with good reaction yields (63.4–84.9%) (Scheme 1). Structural characterization of BR analogs 17–22 was accomplished by using 13C NMR data, combined with 2D NMR techniques (HSQC and HMBC). For

• 13C NMR spectrum, the signals observed at δ = 69.65, 68.38, and 68.27, are assigned to carbinolic carbons C-22, C-3, and C-2, respectively (Figure S33, Supporting Information File 1). In this way, the carbinol signals of H and C were confirmed by correlations to 1JHC, 2JHC, and 3JHC from the 1H,13C

Rongalite addition to dienones: diastereoselectivity in cyclic sulfone synthesis; stereochemical rationalization and prospects as a general conjugate nucleophile

• Melina Goga,
• Hao Zong,
• James Franco,
• Jazmine Prana,
• Rudolph Michel,
• Antonia Muro,
• Elana Rubin,
• Janet Brenya,
• Henk Eshuis and
• Magnus W. P. Bebbington

Beilstein J. Org. Chem. 2026, 22, 742–752, doi:10.3762/bjoc.22.56

• . The major product was isolated and assigned as 5 (from axial attack of a small hydride reagent) [24]. From analysis of the NMR spectra of 5, it was clear that the molecule retained symmetry following reduction, reflected in the reduced number of signals in both 1H and 13C spectra compared to alcohol 4

• shift by a remarkable 1.0 ppm. Similarly, in the 13C NMR spectrum, the ortho-disubsituted ring produces 6 aromatic and 2 aliphatic signals, rather than the 4 aromatic and 1 aliphatic signals that would be expected given the symmetrical aromatic substitution pattern. These data indicate that the ortho

• additions. Results of competition experiments. Supporting Information Supporting Information File 4: Experimental procedures, copies of 1H and 13C NMR spectra and further computational details. Acknowledgements S. Finn and R. Murtada (Montclair State) are acknowledged for mass spectra as are Dr N. Dayal

Anti-invasive and cytotoxic evaluation of a (+)-pinoresinol-based semisynthetic library against glioblastoma

• Chen Zhang,
• Kah Yean Lum,
• Jonathan M. White,
• Paul I. Forster,
• Nicholas Booth,
• Sunita A. Ramesh and
• Rohan A. Davis

Beilstein J. Org. Chem. 2026, 22, 691–704, doi:10.3762/bjoc.22.54

• and MeOH. Subsequent purifications of these two extracts afforded the two known natural products (+)-salicifoliol (1) [15][16] and (+)-pinoresinol (2, Figure 1) [17]. Their structures were determined by 1D (1H and 13C) and 2D (COSY, HMBC, HSQC, and ROESY) NMR spectroscopy together with MS data

• 7.06 (2H), 6.83 (2H)), as well as two methine (δH 4.75 (2H), 3.11 (2H)), one methylene (δH 4.27/3.90, 4H), and one methoxy signal (δH 3.92, 6H)). The 13C NMR and HSQC spectra of 5 indicated a total of 10 unique carbon signals, including one methoxy (δC 56.6, 2C), two methine (δC 85.4, 53.9, 4C), one

• methylene (δC 71.8, 2C), and six aromatic carbon signals (δC 147.6, 142.9, 133.3, 122.3, 108.4, 108.0, 12C). Comparison of the 1H and 13C NMR data of 5 and (+)-pinoresinol (2) showed a high degree of homology, with the major differences in NMR data associated with a chemical shift of the aryl resonances

Regioselective approach to 5-arylsulfonylisoxazoles and their antimicrobial activity

• Artem S. Sazonov,
• Dmitry A. Vasilenko,
• Denis V. Porfiriev,
• Yuri K. Grishin,
• Rimma A. Gazzaeva,
• Alisa P. Chernyshova,
• Maxim A. Kryakvin,
• Anna A. Baranova,
• Vera A. Alferova and
• Elena B. Averina

Beilstein J. Org. Chem. 2026, 22, 592–602, doi:10.3762/bjoc.22.45

• conditions. MIC (μg/mL) against bacterial and fungal lines. Supporting Information Supporting Information File 8: General synthetic and biological procedures, characterization data and copies of 1H, 13C{1H}, 19F, 31P, 1H-13C HSQC, 1H-13C HMBC NMR spectra, HRMS spectra and the results of the elemental

Continuous-flow carbonyl hydrogenation under subatmospheric to atmospheric hydrogen pressure enabled by robust heterogeneous Pt–Fe catalysts

• Hiroyuki Miyamura,
• Ryosuke Kajiyama,
• Shun-ya Onozawa,
• Yoshihiro Kon and
• Shū Kobayashi

Beilstein J. Org. Chem. 2026, 22, 575–582, doi:10.3762/bjoc.22.43

• ) was converted to the corresponding alcohol 2d in 89% yield under continuous-flow conditions at room temperature (Table 2, entry 3). The desired product 2d was obtained quantitatively at 50 °C (Table 2, entry 4). It is noteworthy that an analytically pure compound (confirmed by 1H and 13C NMR) was

• : Additional experimental details, materials, and methods including photographs of reactor systems, STEM-EDS images and XPS spectra of heterogeneous catalysts, and copies of 1H and 13C NMR spectra for isolated compounds. Acknowledgements H. M. also thanks the Joint Usage/Research Center for Catalysis

Kinetic resolution of racemic planar-chiral vinylcymantrenes by molybdenum-catalyzed asymmetric metathesis dimerization

• Haruna Imazu,
• Hitoshi Izu,
• Yasuhiro Ohki and
• Masamichi Ogasawara

Beilstein J. Org. Chem. 2026, 22, 568–574, doi:10.3762/bjoc.22.42

• substrates rac-1a–c. Molybdenum-catalyzed asymmetric metathesis dimerization/kinetic resolution of racemic vinylcymantrenes 1a–c.a Supporting Information Supporting Information File 19: Experimental procedures, NMR spectra (1H and 13C) for all the new compounds, and chiral HPLC chromatograms. Supporting

Experimental and DFT studies on the regioselective methanolysis of 5-azido-9-oxabicyclo[6.1.0]nonan-4-yl 4-nitrobenzoate isomers

• İlknur Polat,
• Selçuk Eşsiz and
• Emine Salamci

Beilstein J. Org. Chem. 2026, 22, 547–556, doi:10.3762/bjoc.22.40

• intermediate 12 with the anti-face of the benzoate to give compound 14. Similarly, the chloride anion attacks by SN2-type the epoxide ring of intermediate 15 to give the sole product 16. The structure of acetate 11 was investigated using 1D (1H and 13C) and 2D (COSY, NOESY, NOE-diff, and HMQC) NMR

• to design pharmacological tools in the future. Experimental General information Melting points are uncorrected. Infrared spectra were obtained from solution in 0.1 mm cells or KBr pellets on an FT-IR Mattson 1000 instrument. The 1H and 13C NMR spectra were recorded on 400 (100) MHz Varian or 400 (100

• . Purification by silica gel column chromatography eluting with EtOAc/hexane 5:95 provided azidol 7 [23] as slightly yellow oil (2.47 g, 14.77 mmol, 92%, lit. [23] 71%). 1H NMR (400 MHz, CDCl3) δ 5.69–5.61 (m, 1H), 5.60–5.52 (m, 1H), 3.79–3.65 (m, 2H), 2.56–2.36 (m, 2H), 2.27–2.09 (m, 4H), 1.81–1.67 (m, 2H); 13C

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

• signals detected in the 13C NMR spectrum of 4 (Table 2) could be assigned by careful analysis of the 2D-NMR spectra (HSQC and HMBC). The position of the acetyl group was confirmed by a cross peak between C-2 and the protons of the acetyl-methyl group in the HMBC spectrum and by interactions between the

• ). The chemical shift values of C-6a and C-10a in the 13C NMR spectrum of 4 compared to 2 can be explained by the effect of the new OH-group at C-10b. The γ-position of C-6a leads to a high field shift (from 46.1 to 35.8 ppm) while C-10a shows the opposite effect (from 27.5 to 44.1 ppm), due to its β

• 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

Get a better glimpse on sequential photoreactions of trisnorbornadienes with ¹⁹F NMR spectroscopy

• Julian Felix Maria Hebborn,
• Ben Eric Merten,
• Thomas Paululat and
• Heiko Ihmels

Beilstein J. Org. Chem. 2026, 22, 527–534, doi:10.3762/bjoc.22.38

• trisnorbornadiene 1f was synthesized in 36% yield through a Suzuki–Miyaura coupling reaction of tribromotrifluorobenzene 3 with the 2-borononorbornadiene 1e (Scheme 2) [43]. The product 1f was identified and fully characterized by NMR spectroscopy (1H, 13C, 19F, COSY, HSQC, HMBC), mass spectrometry, melting point

• '-H, 5'''-H, 5'''-H), 6.94 (dd, 3J = 5.0 Hz, 3J = 2.4 Hz, 3H, 6'-H, 6''-H, 6'''-H), 7.00 (d, 3J = 2.4 Hz, 3H, 3'-H, 3''-H, 3'''-H); 13C NMR (125 MHz, CDCl3) δ 50.7 (C4', C4'', C4'''), 54.6 (C1', C1'', C1'''), 73.1 (C7', C7'', C7'''), 111.2 (C1, C3, C5), 143.1 (C5', C5'', C5'''), 143.4 (C6', C6'', C6

Synthesis and uranyl(VI) extraction performance of a calix[4]pyrrole–tetrahydroxamic acid receptor

• Sara Karnib,
• Rana Baydoun,
• Wissam Zaidan,
• Nancy AlHaddad,
• Omar El Samad,
• Bilal Nsouli,
• Francine Cazier-Dennin and
• Pierre-Edouard Danjou

Beilstein J. Org. Chem. 2026, 22, 486–494, doi:10.3762/bjoc.22.36

• % yield. Its structure was confirmed by 1H NMR, 13C NMR, and HRMS. The uranium(VI) extraction efficiency of PCP HA was evaluated by solid–liquid extraction experiments, using uranyl acetate as the uranium source, with measurements performed by gamma spectroscopy. PCP HA demonstrated good performance

• %). The structure of PCP HA was fully characterized by 1H NMR and 13C NMR (DMSO-d6) as well as by HRMS (ESI+) (Figures S3–S6, and S9 in Supporting Information File 1). In the 1H NMR spectrum, two sets of singlets at 4.41 and 4.76 ppm (CH2) were attributed to the –O=C–CH2–O– groups of the E/Z isomers of

• industrial effluent remediation or for the challenging task of uranium extraction from seawater [79]. Experimental Detailed synthetic procedures, compound characterization (1H and 13C NMR, HRMS), and uranyl extraction protocols, including pH and ligand-to-metal ratio studies, are described in Supporting

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

• , 1H), 7.71 (dd, J = 8.7, 2.3 Hz, 1H), 7.04 (d, J = 8.7 Hz, 1H), 2.93 (s, 6H); 13C NMR (100 MHz, CDCl3) δ 189.7, 156.9, 136.1, 131.1, 130.0, 119.5, 116.7, 43.6. 12-(3-Bromo-4-(dimethylamino)phenyl)-8,9,10,12-tetrahydro-9,9-dimethylbenzo[a]acridin-11(7H)-one (2); suggested revised structure for compound

• ), 2.51 (s, 6H), 2.39 (d, J = 16.5 H, 1Hz), 2.18 (d, J = 16.0 Hz, 1H), 2.02 (d, J = 16.0 Hz, 1H), 0.99 (s, 3H), 0.85 (s, 3H). One diastereotopic methylene hydrogen is obscured by the residual solvent peak at 2.47 ppm; 13C NMR (100 MHz, DMSO-d6) δ 193.72, 151.37, 149.50, 143.73, 134.80, 132.80, 131.69

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

• procedures, characterization data, copies of 1H and 13C NMR spectra, and optimized geometries of DFT calculations. Supporting Information File 26: Crystallographic information file of compound 1ac. Acknowledgements We thank K. Imamura (Evaluation center of material properties, IMCE Kyushu University) for

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

• 1.80 ppm and one triplet at 3.13 ppm were attributed to the remaining methylene protons located near the selenium atom [51]. In the 13C NMR spectra, distinct chemical shift differences were observed between compounds 7 and 8, due to the small structural differences between them. For compound 7, with

• reference to 13C NMR signals of the starting material 12, the 13C NMR spectrum of compound 7 exhibits four additional aromatic carbon resonances, which are consistent with the phenyl ring carbons of phenyl selanyl function tethered to the naphthalimide core. The signal at 142 ppm is assigned to the ipso

• equivalence of the ortho and meta carbon pairs, confirming the proposed structure. In contrast, with reference to the 13C NMR signals of starting material 12, compound 8 exhibited eight new 13C NMR peaks in the aliphatic region (14–32 ppm), which is attributed to the incorporation of an octyl selenide unit

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

• calixarenes 12 and 13, 1H,13C HMBC spectra were acquired (Figure 2), which clearly showed that the nitro groups are attached to the propylated aromatic units of the macrocycle in both cases. Notably, the correlations showed that the signals from the nitrated calixarene aromatic units appeared upfield-shifted

• corresponding tetraureacalix[4]arenes 47–51 (Scheme 9), the structures of which were unambiguously confirmed by their 1H NMR and 13C NMR spectra obtained from solutions in polar DMSO-d6. Being calix[4]arene tetraureas, compounds 47–51 should form homodimeric capsules in H-bond non-competing solvents (e.g

• ]arenes by joining propargyl/2-azidoethyl and p-amino groups on a common platform. Parts of 1H,13C HMBC spectra of calixarenes 12 (a) and 13 (b) recorded in CDCl3 solutions at 600 MHz. Red lines show the key correlations between signals from the calixarene narrow-rim substituents and aromatic units

Design, synthesis and biological evaluation of 2,5-diaryloxazolo[4,5-d]pyrimidin-7-ylamines as selective cytotoxic agents against HeLa cells

• Maryna V. Kachaeva,
• Agnieszka B. Olejniczak,
• Marta Denel-Bobrowska,
• Victor V. Zhirnov,
• Yevheniia S. Velihina,
• Stepan G. Pilyo and
• Volodymyr S. Brovarets

Beilstein J. Org. Chem. 2026, 22, 390–398, doi:10.3762/bjoc.22.27

• Analytique, Université d’Orléans, Pôle de chimierue de Chartres, BP 6759, 45067 Orléans Cedex 2, France 10.3762/bjoc.22.27 Abstract Nine novel functionalized 2,5-diaryloxazolo[4,5-d]pyrimidin-7-ylamines were designed, synthesized and characterized using 1H, 13C NMR, IR spectroscopy, elemental analysis, and

• cyclocondensation products – [1,3]oxazolo[4,5-d]pyrimidines. Subsequent reaction with phosphoryl chloride in the presence of N,N-dimethylaniline converted these intermediates into 2,5-diaryl-7-chloro[1,3]oxazolo[4,5-d]pyrimidines II. The structures of compounds 1–9 were proven and confirmed by 1H and 13C NMR, IR

• were followed by TLC (Silica gel, aluminum sheets 60 F254, Merck). Melting points were recorded on a Fisher-Johns apparatus. 1H and 13C NMR spectra were recorded on a Varian Mercury spectrometer (400 and 101 MHz, respectively) or Bruker Avance DRX 500 spectrometer (500 MHz and 126 MHz, respectively) in

Spirobarbiturates with a pyrrolizidine moiety: synthesis, structure and biological evaluation

• Arthur A. Puzyrkov,
• Andrew S. Drachuk,
• Ekaterina A. Popova,
• Alexander V. Stepakov and
• Vitali M. Boitsov

Beilstein J. Org. Chem. 2026, 22, 274–288, doi:10.3762/bjoc.22.20

• were established using 1H,13C HSQC NMR spectroscopy. The chemical shift values, signal shapes, and spin–spin coupling constants are provided in Table S1 in Supporting Information File 1. The aromatic protons of compounds 4c–e appear in the downfield region of the spectrum. For product 4c, the aromatic

• the diastereotopic H6/H6’ methine protons of different atropisomeric forms. The NH protons of the barbiturate ring resonate as broad singlets at δ 11.5–11.7 ppm, while compound 4a shows an additional broad singlet at δ 11.30 ppm corresponding to the succinimide NH group. In the 13C NMR spectra of endo

• –169.4, 171.2–171.5, 175.5–176.8, and 176.4–177.9 ppm. The spiro carbon appears at δC 70.1–70.3 ppm. For diastereomers 4f–p, the 13C NMR spectra proved more informative than the 1H NMR spectra, clearly displaying a duplicate set of nearly all signals. The chemical shifts of carbons in rings A, B, and C

A mild and atom-efficient four-component cascade strategy for the construction of biologically relevant 4-hydroxyquinolin-2(1H)-one derivatives

• Dmitrii A. Grishin,
• Kseniia I. Sharkovskaia,
• Ilya G. Kolmakov,
• Daria A. Ipatova,
• Rostislav A. Petrov,
• Nikolai D. Dagaev,
• Dmitry A. Skvortsov,
• Maria G. Khrenova,
• Valeriy V. Andreychev,
• Sergei A. Evteev,
• Yan A. Ivanenkov,
• Roman L. Antipin,
• Olga А. Dontsova and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2026, 22, 244–256, doi:10.3762/bjoc.22.18

• well-known topoisomerase II inhibitor doxorubicin (see Supporting Information File 1, page S52), whose toxicity correlates with the cell proliferation rate. Compounds 13b and 13c exhibited non-specific toxicity across all tested cell lines. Antibacterial activities of compounds 9–14 were evaluated in

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

• without further purification. Instruments and measurements Low-resolution mass spectra were recorded on a DSQ electron-impact (EI) mass spectrometer. High-resolution mass spectra (HRMS) were acquired on a Thermo MAT95XP instrument using fast atom bombardment (FAB) ionization. 1H and 13C NMR spectra were

• ), 7.30 (d, 2H), 2.37 (s, 3H); 13C NMR (126 MHz, DMSO-d6) δ 167.23, 145.94, 140.78, 140.61, 138.29, 133.75, 133.11, 132.41, 131.58, 131.15, 129.34, 128.56, 127.85, 127.57, 127.08, 126.82, 126.05, 124.56, 123.30, 122.35, 121.02, 120.64, 110.24; EIMS (m/z): [M]+ calcd for C33H22N2O2, 478.1681; found