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

• 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

Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• unsymmetrical oxaza[8]helicenes 5. Chiroptical features of oxaza[8]helicenes 5 and oxaza[7]helicenes 6. Supporting Information Supporting Information File 9: Experimental procedures, synthetic details, NMR spectra, chiral HPLC chromatograms, DFT and TD-DFT calculations. Supporting Information File 10

Synthesis of tricyclic fused pyrrolidine nitroxides from 2-alkynylpyrrolidine-1-oxyls

• Mark M. Gulman,
• Yuliya F. Polienko,
• Sofia Yu. Trakhininа,
• Yuri V. Gatilov,
• Tatyana V. Rybalova,
• Sergey A. Dobrynin and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2026, 22, 344–351, doi:10.3762/bjoc.22.22

• nitroxides 2d–f, the samples of the radicals were reduced to the corresponding diamagnetic amines using a Zn/CF3COOH system in CD3OD at 63 °C, according to a literature protocol [23] and the 1H NMR spectra were recorded. The spectra showed similarity to those of previously described for radicals 2a–c [20

• sulfonate group, respectively [24]. The 1H NMR spectra of 3a,b,d–f (Zn/CF3COOH system in CD3OD) showed appearance of a singlet of methanesulfonate hydrogens in the region from 2.78 to 3.17 ppm. The NMR spectra were not recorded for 3c because of heavy resinification upon the sample preparation. The

• % yield). The IR spectra of the pyrazole derivatives 9a–c exhibit absorptions at 688–699 cm−1 and 763–770 cm−1, assigned to out-of-plane bending modes of the pyrazole ring [32]. The 1H NMR spectra of the reduction products of pyrazoles 9a–c were recorded after reduction using the Zn/CF3COOH system 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

• configuration of their stereocenters, was determined using NMR spectroscopy and XRD analysis. endo-Isomers 4a–e exhibited the following characteristic signals in their 1H NMR spectra: multiplets in the range of δ 1.5–4.4 ppm were assigned to the protons of the pyrrolizidine ring system. The methyl singlets of

• : 4d shows signals at δ 7.12 and 7.30 ppm for ortho- and meta-protons respectively (J = 8.2 Hz) and 4e displays resonances at δ 7.58 and 8.41 ppm for ortho- and meta-protons (J = 8.8 Hz). In the 1H NMR spectra, the proton signals of ring A in diastereomers 4f–p overlap and appear at the same chemical

• 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

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

Synthesis of diaryl phosphates using phytic acid as a phosphorus source

• Kazuya Asao,
• Seika Matsumoto,
• Haruka Mori,
• Riku Yoshimura,
• Takeshi Sasaki,
• Naoya Hirata,
• Yasuyuki Hayakawa and
• Shin-ichi Kawaguchi

Beilstein J. Org. Chem. 2026, 22, 213–223, doi:10.3762/bjoc.22.15

• acid molecule (Figure 6 and Figure S3 in Supporting Information File 1) [57][58][59]. The full 1H, 13C, and 31P NMR spectra are provided in Supporting Information File 1. Next, the extracted phytic acid was used for phosphate synthesis. Although the reaction was conducted under the same conditions as

• (SHIMADZU, Kyoto, Japan) and JMS GC-mate II (JEOL, Tokyo, Japan) instruments. The melting points were determined using a Q-200 differential scanning calorimeter (TA Instruments, New Castle, DE, USA). The NMR spectra were recorded in a deuterated solvent (D2O, methanol-d4 or dimethyl sulfoxide (DMSO)-d6

• )), and the residual solvent was set to the chemical shift reference for 1H NMR (H2O, δ 4.79 ppm; MeOH, δ 3.31 ppm; DMSO, δ 2.50 ppm). All NMR spectra were compared with those reported in previous studies [15][46][47][48] and found to be consistent with the references. The spectra are provided in

Base-promoted deacylation of 2-acetyl-2,5-dihydrothiophenes and their oxygen-mediated hydroxylation

• Vladimir G. Ilkin,
• Margarita Likhacheva,
• Igor V. Trushkov,
• Tetyana V. Beryozkina,
• Vera S. Berseneva,
• Vladimir T. Abaev,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2026, 22, 192–204, doi:10.3762/bjoc.22.13

• : Full experimental details and characterization data of all new compounds. Supporting Information File 18: Copies of NMR spectra of all new compounds. Supporting Information File 19: CIF-file for compound 5g. Supporting Information File 20: CheckCIF-file for compound 5g. Funding We gratefully

Streptoquinolines A and B, new antibacterial meroterpenoids produced by Streptomyces sp. TMPU-A0679

• Akiho Yagi,
• Hitomi Tomura,
• Ami Konno and
• Ryuji Uchida

Beilstein J. Org. Chem. 2026, 22, 185–191, doi:10.3762/bjoc.22.12

• . Streptoquinoline B (2): The molecular formula of compound 2 was elucidated as C28H35NO6 based on HRESIMS measurements. The 13C NMR and 1H NMR spectra (in DMSO-d6) of compound 2 showed chemical shift values that were almost identical to those of compound 1 (Table 2). Furthermore, 2D NMR experiments revealed similar

• Kyokuto Pharmaceutical Co. (Tokyo, Japan). All other chemicals used in this study were of special grade. General experimental procedures HRESIMS spectra were recorded using a mass spectrometer (Xevo G2-XS QTof, Waters Co., Milford, MA, USA). NMR spectra were acquired on a spectrometer (JNM-AL-400; JEOL

• ) and B (2). Structural elucidation of compounds 1 and 2 by 2D NMR experiments. ROESY correlations of 1. Physicochemical properties of 1 and 2. 1H and 13C NMR chemical shifts in 1 and 2.a MICs of 1 and 2. Supporting Information Supporting Information File 12: MS and NMR spectra of streptoquinolines A

Improved synthesis and physicochemical characterization of the selective serotonin 2A receptor agonist 25CN-NBOH

• Adrian G. Rossebø,
• Hannah G. Kolberg,
• Anders E. Tønder,
• Louise Kjaerulff,
• Poul Erik Hansen,
• Karla A. Frydenvang,
• Jesper Østergaard and
• Jesper L. Kristensen

Beilstein J. Org. Chem. 2026, 22, 175–184, doi:10.3762/bjoc.22.11

• bond [21]. When measuring 13C NMR spectra in DMSO-d6 containing different D2O/H2O ratios, isotope effects were clearly observed at several positions (Figure 6c and Figure 6d), with a particularly pronounced upfield shift of the phenol ipso-carbon atom (C14, Δδexp = 0.21 ppm). This two-bond isotope

• precoated with silica gel 60 F254 (Merck KGaA, Darmstadt, Germany), and retention factors are denoted Rf. Graphs were produced using GraphPad Prism 10.5, except for NMR spectra, where MestReNova was used. ChemDraw 23.1.2 was used to draw chemical structures. Synthesis of 25CN-NBOH·HCl (1·HCl) To a slurry of

• approach [30]. To ensure gauge independence, nuclear shielding was calculated using the GIAO approach [31][32]. NMR spectroscopy NMR spectra were acquired on a 600 MHz Bruker Avance III HD spectrometer equipped with a 5 mm DCH cryoprobe at 300 K unless otherwise specified. Spectra were processed using

Asymmetric Mannich reaction of aromatic imines with malonates in the presence of multifunctional catalysts

• Kadri Kriis,
• Harry Martõnov,
• Annette Miller,
• Mia Peterson,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2026, 22, 151–157, doi:10.3762/bjoc.22.8

• 20: Experimental procedures, synthetic details, NMR spectra, chiral HPLC chromatograms. Funding The research was funded by the Estonian Ministry of Education and Research (grant No. PRG1031).

Design and synthesis of an axially chiral platinum(II) complex and its CPL properties in PMMA matrix

• Daiki Tauchi,
• Sota Ogura,
• Misa Sakura,
• Kazunori Tsubaki and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2026, 22, 143–150, doi:10.3762/bjoc.22.7

• and 13C NMR spectra were recorded on a Bruker Avance III 400 or JEOL JNM-ECZ600R spectrometer at 25 °C in chloroform-d1 or DMSO-d6. 1H NMR chemical shifts are expressed in parts per million (δ) relative to trimethylsilane (TMS) as a reference. Mass spectra were obtained with a Thermo Scientific

Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure

• Ilia A. Pilipenko,
• Mikhail V. Grigoriev,
• Olga Yu. Ozerova,
• Igor A. Litvinov,
• Darya V. Spiridonova,
• Aleksander V. Vasilyev and
• Sergey V. Makarenko

Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5

• use of method E in the reaction of 1-bromo-1-nitro-3,3,3-trichloropropene (1) with methyl cyanoacetate, ethyl cyanoacetate or benzoylacetonitrile makes it possible to obtain cyclopropanes 3–5 in the yields up to 72% (Scheme 2). They are formed as single diastereomers (according to the 1H NMR spectra

• Diffraction Research Methods of the A. E. Arbuzov Institute of Organic and Physical Chemistry, the Kazan Scientific Center of the Russian Academy of Sciences. The 1H-13C{1H}, 1H-1H dqfCOSY, 1H-1H NOESY, 1H-13C HMQC, 1H-13C HMBC NMR spectra were recorded on a Jeol ECX400A spectrometer operating at 399.78 MHz

• the structure are shown in Table S1 in Supporting Information File 1. Supporting Information File 14: General synthetic procedures, characterization data and copies of IR spectra, 1H-13C{1H}, 1H-1H dqfCOSY, 1H-1H NOESY, 1H-13C HMQC, 1H-13C HMBC NMR spectra of all synthesized compounds, and

Reactivity umpolung of the cycloheptatriene core in hexa(methoxycarbonyl)cycloheptatriene

• Dmitry N. Platonov,
• Alexander Yu. Belyy,
• Rinat F. Salikov,
• Kirill S. Erokhin and
• Yury V. Tomilov

Beilstein J. Org. Chem. 2026, 22, 64–70, doi:10.3762/bjoc.22.2

• , quantum chemical calculation details and copies of NMR spectra. Funding This work was financially supported by the Russian Science Foundation (Grant No. 25-23-00616).

Sustainable electrochemical synthesis of aliphatic nitro-NNO-azoxy compounds employing ammonium dinitramide and their in vitro evaluation as potential nitric oxide donors and fungicides

• Alexander S. Budnikov,
• Nikita E. Leonov,
• Michael S. Klenov,
• Andrey A. Kulikov,
• Igor B. Krylov,
• Timofey A. Kudryashev,
• Aleksandr M. Churakov,
• Alexander O. Terent’ev and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2025, 21, 2739–2754, doi:10.3762/bjoc.21.211

• hygroscopic nature. Any manipulations must be carried out by using appropriate standard safety precautions. 1H, 13C, 14N NMR spectra were recorded with Bruker DRX-500 (500.1, 125.8, 36.1 MHz, respectively) and Bruker AV600 (600.1, 150.9, 43.4 MHz, respectively) spectrometers. Chemical shifts are reported in

• all compounds, XRD of 2c, computational details, and copies of 1H, 13C, 14N, 1H,13C HSQC, and 1H,13C HMBC NMR spectra. Supporting Information File 5: Crystallographic information for compound 2c. Supporting Information File 6: CheckCIF report for the data of 2c. Acknowledgements Crystal structure

Competitive cyclization of ethyl trifluoroacetoacetate and methyl ketones with 1,3-diamino-2-propanol into hydrogenated oxazolo- and pyrimido-condensed pyridones

• Svetlana O. Kushch,
• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess,
• Pavel A. Slepukhin,
• Alexandrina S. Volobueva,
• Vladimir V. Zarubaev and
• Victor I. Saloutin

Beilstein J. Org. Chem. 2025, 21, 2716–2729, doi:10.3762/bjoc.21.209

• –1628 cm−1 and NH2 groups at ν 3376–3272 cm−1. The structures of the obtained heterocycles 4 and 5 contain three stereocenters, so one could expect the formation of up to 8 stereoisomers in each case. Analysis of the 19F NMR spectra showed that from two to four diastereomers of

• crystal 4a–d and 5a–c are in excellent agreement with the results of 1D and 2D NMR studies, enabling us to extend these structural assignments to other synthesized bicycles. The complete assignment of signals in 1H and 13C NMR spectra was performed using two-dimensional 1H-1H COSY, NOESY and 1H-13C HSQC

• , whereas in the trans-configuration of the hexahydropyrimidine ring, a cross-peak (OHax, H(2)eq) appears in the spectrum. In the 1H NMR spectra of octahydropyrido[1,2-a]pyrimidinones 4att, 4a–dct, which have the trans-configuration of the hexahydropyrimidine ring, the signal of the H(3) proton has the form

Tandem hydrothiocyanation/cyclization of CF₃-iminopropargyl alcohols with NaSCN in the presence of AcOH

• Ruslan S. Shulgin,
• Ol’ga G. Volostnykh,
• Anton V. Stepanov,
• Igor’ A. Ushakov,
• Alexander V. Vashchenko and
• Olesya A. Shemyakina

Beilstein J. Org. Chem. 2025, 21, 2694–2702, doi:10.3762/bjoc.21.207

• formation and ratio of the products in contrast to the substituents in the imine fragment. NMR monitoring of reactions (1a/NaSCN/AcOH or 1g/NaSCN/AcOH in MeCN) did not allow to detect any intermediates even when the temperature was lowered to 0 °C. In the 1H and 19F NMR spectra the signals of products 2a

• and 3a appeared immediately upon mixing the starting reagents (Figure 1a and b). This indicated that the cyclization occurred almost immediately. Moreover, in the NMR spectra of the 1g/NaSCN/AcOH reaction mixture in MeCN we detected signals assigned to isothiozolium salt 2g (1H NMR: δ 8.30 s (CH

• operational simplicity, relatively mild conditions and readily prepared starting materials. Experimental General information. 1Н, 13С {1H}, and 19F NMR spectra were recorded on a Bruker DPX-400 spectrometer (400.1, 100.6, and 376 MHz, respectively) in CDCl3 and (CD3)2CO using hexamethyldisiloxane (HMDS) as

Synthesis of new tetra- and pentacyclic, methylenedioxy- and ethylenedioxy-substituted derivatives of the dibenzo[c,f][1,2]thiazepine ring system

• Gábor Berecz,
• András Dancsó,
• Mária Tóthné Lauritz,
• Loránd Kiss,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2645–2656, doi:10.3762/bjoc.21.205

• standard open 40 μL aluminum pan under 50 mL/min nitrogen atmosphere. IR spectra were obtained on a Bruker ALPHA FT-IR spectrometer in KBr pellets or in neat. NMR spectra were recorded at 295 K on a Bruker Avance III HD 600 (600 and 150 MHz for 1H and 13C NMR spectra, respectively) spectrometer equipped

• with a Prodigy cryo-probehead or a Varian Unity Inova 500 (500 and 125 MHz for 1H and 13C NMR spectra, respectively), or a Varian Unity Inova 400 (400 and 100 MHz for 1H and 13C NMR spectra, respectively), or a Varian Gemini 200 (200 and 50 MHz for 1H and 13C NMR spectra, respectively) spectrometer

• was used as the solvent and tetramethylsilane (TMS) as the internal standard. Chemical shifts (δ) and coupling constants (J) are given in ppm and in Hz, respectively. Coupling constants reported in the 1H NMR spectra are H–H couplings unless otherwise stated (J ≡ JH–H). Three-bond H–H couplings (3J

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

• compounds 3n and 4n was carried out using torsion angle analysis and 13C NMR chemical shift calculations to evaluate the absence of expected signals in the NMR spectra of these compounds. Their photophysical properties were also assessed, confirming a preference for a fluorescence mechanism via an ICT

• and 4n During the characterization of the compounds obtained in our study to determine the reaction scope, an anomaly was observed in the NMR spectra of products 3n and 4n derived from 4-diethylaminobenzaldehyde (see Supporting Information File 1). The spectra were acquired at 600 MHz for 1H NMR (320

• interactions are observed in both compounds forming dimer-like structures. The compounds show hydrogen bonds between N1–H1···O1’ with a distance of 2.06 Å in 3n (Figure 4b) and 1.98 Å in 4n (Figure S250b in Supporting Information File 1). The anomaly observed in the NMR spectra may be attributed to

Silica gel with covalently attached bambusuril macrocycle for dicyanoaurate sorption from water

• Michaela Šusterová and
• Vladimír Šindelář

Beilstein J. Org. Chem. 2025, 21, 2604–2611, doi:10.3762/bjoc.21.201

• carried out in nitrogen atmosphere. The dicyanoaurate concentration in solution was determined according to UV–vis spectra recorded with a CARY 60 spectrophotometer (Agilent Technologies). NMR spectra were recorded on a Bruker Avance III 300 spectrometer (300.15 Hz, 298.15 K). Preparation of SG-NHCO-BU1

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

• structures of aglacins A, B, C, and E. Retrosynthetic analysis of (+)-aglacin B (2). Synthesis of cyclization precursor 5. Synthesis of (+)-aglacin B (2). Supporting Information Supporting Information File 16: Experimental procedures, characterization data, and copies of 1H/13C NMR spectra

Synthesis and characterization of a isothiouronium-calix[4]arene derivative: self-assembly and anticancer activity

• Giuseppe Granata,
• Loredana Ferreri,
• Claudia Giovanna Leotta,
• Giovanni Mario Pitari and
• Grazia Maria Letizia Consoli

Beilstein J. Org. Chem. 2025, 21, 2535–2541, doi:10.3762/bjoc.21.195

• precipitate was recovered by filtration and washed several times with ethyl ether, to give pure compound 3 (118 mg, 96% yield). Characterization of compound 3: NMR spectra were acquired on a Bruker Avance 400TM spectrometer. Chemical shifts (δ, ppm) are reported referring to the residual peak of the solvent

Pentacyclic aromatic heterocycles from Pd-catalyzed annulation of 1,5-diaryl-1,2,3-triazoles

• Kaylen D. Lathrum,
• Emily M. Hanneken,
• Katelyn R. Grzelak and
• James T. Fletcher

Beilstein J. Org. Chem. 2025, 21, 2524–2534, doi:10.3762/bjoc.21.194

• Supporting Information Supporting Information File 4: Description of materials, experimental methods, synthetic procedures, analytical characterization and copies of NMR spectra for novel compounds. Funding Research reported in this publication was supported by the National Institute of General Medical

Effect of a photoswitchable rotaxane on membrane permeabilization across lipid compositions

• Udyogi N. K. Conthagamage,
• Lilia Lopez,
• Zuliah A. Abdulsalam and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2498–2512, doi:10.3762/bjoc.21.192

• the compounds, while chloroform was used for cholesterol and lipid stock solutions. 1H NMR spectra were recorded using Bruker AV III 400 and Bruker AV III 500 spectrometers. 13C NMR was conducted on a Bruker AV III 500 spectrometer. All chemical shifts (δ) are reported in ppm, referencing residual non

Assembly strategy for thieno[3,2-b]thiophenes via a disulfide intermediate derived from 3-nitrothiophene-2,5-dicarboxylate

• Roman A. Irgashev

Beilstein J. Org. Chem. 2025, 21, 2489–2497, doi:10.3762/bjoc.21.191

• -nucleophiles to form sulfide 2 and disulfide 3. Optimization of the reaction conditions for the reduction–alkylation of disulfide 3. Supporting Information Supporting Information File 12: Full experimental details, characterization data, copies of NMR spectra and HRMS for all new compounds. Acknowledgements

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

• 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