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

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

• subsequently activated with light at the site of illness with high spatiotemporal resolution. Thus, collateral damage in the surrounding healthy tissue can be avoided. In addition, the quantitative thermal back-isomerization from the active E to the inactive Z configuration prevents contamination and

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

• mRNA domain, namely the preQ1 class-I riboswitch (preQ1-I) from Thermoanaerobacter tengcongensis. By rigorously analyzing the high-resolution structures available for this ligand–RNA complex, the approach exploits the natural, sequence-inherent reactivity hotspots of RNA and thus avoids the use of

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

• , Universidad de Valladolid, Paseo Belén 7, 47011-Valladolid, Spain 10.3762/bjoc.21.34 Abstract The pharmaceutical chemical industry has long used kinetic resolution to obtain high-value compounds. Organocatalysis has recently been added to this strategy, allowing for the resolution of racemic mixtures with

• low catalyst loadings and mild reaction conditions. This research focuses on the kinetic resolution of 1,5-dicarbonyl compounds using a retro-Michael reaction, co-catalyzed at room temperature with 20 mol % of the Jørgensen–Hayashi catalyst and PNBA. The study highlights the importance of conducting

• the kinetic resolution at a concentration of approximately ten millimolar (mM) to prevent the Michael retro-Michael equilibrium from affecting the process. Keywords: 1,5-dicarbonyl; equilibrium; kinetic resolution; organocatalysis; retro-Michael; Introduction For many years, enantiomers have been

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

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

• range from 190 to 600 nm. High-resolution electrospray ionization mass spectra (HRESIMS) were obtained using an Agilent 1200 Infinity Series HPLC-UV system (Agilent Technologies, Santa Clara, CA, USA) equipped with a C18 Acquity UPLC BEH analytical column (50 × 2.1 mm, 1.7 µm; Waters, Milford, MA, USA

Oxidation of [3]naphthylenes to cations and dications converts local paratropicity into global diatropicity

• Abel Cárdenas,
• Zexin Jin,
• Yong Ni,
• Jishan Wu,
• Yan Xia,
• Francisco Javier Ramírez and
• Juan Casado

Beilstein J. Org. Chem. 2025, 21, 277–285, doi:10.3762/bjoc.21.20

• , 2000 scans at a resolution better than 4 cm−1 were accumulated to optimize the signal-to-noise ratio. Theoretical methods Quantum chemistry was addressed with the Gaussian 09 suite of programs [28]. DFT calculations were performed at the (U)B3LYP[29][30] level, using the 6-311G* basis set [31]. This

Effect of substitution position of aryl groups on the thermal back reactivity of aza-diarylethene photoswitches and prediction by density functional theory

• Misato Suganuma,
• Daichi Kitagawa,
• Shota Hamatani and
• Seiya Kobatake

Beilstein J. Org. Chem. 2025, 21, 242–252, doi:10.3762/bjoc.21.16

• , various application examples of molecular photoswitches have been reported so far including volumetric 3D printing [12][13], photoresponsive semiconductors [14][15][16][17], photopharmacology [18][19], energy storage materials [20][21][22][23], data storage materials [24], super-resolution microscopy [25

• previous work [56][57], whereas compounds N4 and I1–I4 were synthesized according to Scheme 2 in the Experimental section. The chemical structures of all compounds were confirmed by 1H NMR and 13C NMR spectroscopy and high-resolution mass spectrometry. 1H NMR and 13C NMR spectra are shown in Supporting

• by distillation before use. 1H NMR (300 MHz) and 13C NMR (75 MHz) spectra were recorded on a Bruker AV-300N spectrometer with tetramethylsilane (TMS) as the internal standard. High-resolution mass spectra (HRMS) were measured on a JEOL AccTOF LC mass spectrometer. UV–vis absorption spectra were

Recent advances in electrochemical copper catalysis for modern organic synthesis

• Yemin Kim and
• Won Jun Jang

Beilstein J. Org. Chem. 2025, 21, 155–178, doi:10.3762/bjoc.21.9

• enantioselectivity. First, the reaction of ketimine ester 33 and 2,3-dimethylhydroquinone at 10 °C provided the chiral 1,4-addition product 35 via dynamic kinetic asymmetric transformation (DyKAT). Conversely, when the reaction was performed at −10 °C, the reaction pathway switched from DyKAT to kinetic resolution

Nickel-catalyzed cross-coupling of 2-fluorobenzofurans with arylboronic acids via aromatic C–F bond activation

• Takeshi Fujita,
• Haruna Yabuki,
• Ryutaro Morioka,
• Kohei Fuchibe and
• Junji Ichikawa

Beilstein J. Org. Chem. 2025, 21, 146–154, doi:10.3762/bjoc.21.8

• detected [40]. High-resolution mass spectrometry (HRMS) analysis of the reaction mixture also supported the formation of Eb (calcd, 804.4474; found, 804.4449). Additionally, 79% of 1b remained, while the catalytic reaction between 1b and 2a was completed in 13 h, yielding 3ba in 96% (Scheme 2). These

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

• enantioselectivities in similar desymmetrization reactions [39][40][41][42]. The dynamic kinetic resolution (DKR) of racemic 2-arylbenzaldehydes 62 with α-bromoenals 63 led to axially chiral products 64 [43]. Triazolium salt C20 as an NHC pre-catalyst was the most efficient for achieving high yields and enantiomeric

• enantioselectivities. Compound 66d was incorporated into a thiourea organocatalyst framework and successfully tested in kinetic resolution with 73% enantioselectivity. The chiral phosphoric acid (CPA) (R)-C22 was used to catalyze the formation of a C–N chiral axis in the axially chiral product 68 from biarylamines 67

• enantioselectivity during the nucleophilic addition, and the subsequent aromatization completes central-to-axial chirality conversion delivering products 68. Dynamic kinetic resolution of naphthylindoles 69 was performed by reaction with bulky electrophiles such as azodicarboxylates 70 or o-hydroxybenzyl alcohols 72

Synthesis, structure and π-expansion of tris(4,5-dehydro-2,3:6,7-dibenzotropone)

• Yongming Xiong,
• Xue Lin Ma,
• Shilong Su and
• Qian Miao

Beilstein J. Org. Chem. 2025, 21, 1–7, doi:10.3762/bjoc.21.1

• Scholl reaction conditions. The structure of 3 was confirmed with single crystal X-ray crystallography, as detailed later. In addition, another product with a molecular ion peak of 1695.9115 in the high-resolution mass spectrum (Supporting Information File 1, Figure S6) was isolated in trace amounts

Enantioselective regiospecific addition of propargyltrichlorosilane to aldehydes catalyzed by biisoquinoline N,N’-dioxide

• Noble Brako,
• Sreerag Moorkkannur Narayanan,
• Amber Burns,
• Layla Auter,
• Valentino Cesiliano,
• Rajeev Prabhakar and
• Norito Takenaka

Beilstein J. Org. Chem. 2024, 20, 3069–3076, doi:10.3762/bjoc.20.255

• propargyltrichlorosilane [35][36] (Scheme 2). Other notable asymmetric catalytic approaches to prepare α-allenic alcohols (R2 = H) include the Corey–Bakshi–Shibata reduction of allenyl ketones [37], enzymatic [38][39][40], non-enzymatic [41] kinetic resolution of racemic α-allenic alcohols, and asymmetric 1,4

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

4,6-Diaryl-5,5-difluoro-1,3-dioxanes as chiral dopants for liquid crystal compositions

• Maurice Médebielle,
• Peer Kirsch,
• Jérémy Merad,
• Carolina von Essen,
• Clemens Kühn and
• Andreas Ruhl

Beilstein J. Org. Chem. 2024, 20, 2940–2945, doi:10.3762/bjoc.20.246

• still remain elusive and are not well understood [29]. Recently we have become interested in the preparation of racemic [30] anti- and highly enantioenriched 2,2-difluoro-1,3-diols [30][31][32] through an acylative double catalytic kinetic resolution (DoCKR) process [33]. While the 1,3-diol motif is

Synthesis of tricarbonylated propargylamine and conversion to 2,5-disubstituted oxazole-4-carboxylates

• Kento Iwai,
• Akari Hikasa,
• Kotaro Yoshioka,
• Shinki Tani,
• Kazuto Umezu and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2024, 20, 2827–2833, doi:10.3762/bjoc.20.238

• -4200 spectrometer equipped with an ATM detector. High-resolution mass spectra (HRMS) were obtained with a Bruker compact mass spectrometer APCI–TOF set at positive mode. The melting point was measured on an SRS-OptiMelt automated melting point system. Preparation of N,O-acetal 1 In a manner analogous

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

• Parvathy Mini,
• Michael R. Grace,
• Genevieve H. Dennison and
• Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

• conditions. High-resolution mass spectrometry (HRMS) analysis and the 1H NMR spectrum were consistent with formation of the Tb.1 complex (Figures S1 and S2 in Supporting Information File 1). Luminescence characterization of Tb.1 As anticipated, based on the previously reported europium complex ([Eu(triazole

• magnetic resonance (1H NMR) spectra was recorded on a Bruker DRX400 spectrometer operating at 400 MHz. High-resolution mass spectrometry (HRMS) was performed using a Bruker BioApex 47e FTMS with an analytical electrospray source employing NaI for accurate mass calibration (ESI). UV–vis absorption spectra

Synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones

• Ruben Manuel Figueira de Abreu,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2708–2719, doi:10.3762/bjoc.20.228

• ), strong (s), medium (m), weak (w) or very weak (vw). UV–vis spectra were recorded on a Cary 60 UV–vis spectrophotometer and emission spectra were recorded on an Agilent Cary Eclipse fluorescence spectrophotometer. Basic and high-resolution mass spectra (MS/HRMS) were measured on instruments coupled to a

The scent gland composition of the Mangshan pit viper, Protobothrops mangshanensis

• Jonas Holste,
• Paul Weldon,
• Donald Boyer and
• Stefan Schulz

Beilstein J. Org. Chem. 2024, 20, 2644–2654, doi:10.3762/bjoc.20.222

• acids, comparison with in-house and other spectral libraries revealed no close match with known compounds. High-resolution EI gas chromatography (HREI–GC–MS) of compound D suggested a molecular formula of C14H26O2 (m/z 226.18962 [M]+, calcd 226.19328), and two double-bond equivalents. The characteristic

• column (30 m × 0.25 mm, 0.25 µm film thickness) with helium as the carrier gas. The eluted compounds were applied to a ZnSe disk rotating at 4 mm/min at −40 °C. The resulting IR spectra were processed using GRAMS/AI 9.2 software (Thermo Fisher Scientific). High-resolution mass spectrometry data were

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

• structures. Some of the key features and capabilities of these techniques are summarised in Table 1. CLSM is a fluorescence microscopy technique capable of acquiring high-resolution optical images at selected depths of the sample. This is achieved by exciting compounds with laser light and, by using a

• pinhole to select focal planes, allows fluorescence at various depths to be focused and imaged. The resulting 2D focal plane images can be stacked to yield a 3D fluorescence image of high resolution, allowing complex morphologies to be visualised (Figure 2) [11]. While CLSM provides in situ 3D imaging

• systems are indeed representative. CLSM also often has poor resolution due to the use of light used for imaging. Other fluorescent imaging techniques such as super resolution fluorescence microscopy (for example, stimulated emission depletion (STED) microscopy or point accumulation for imaging in

Synthesis and cytotoxicity studies of novel N-arylbenzo[h]quinazolin-2-amines

• Battini Veeraiah,
• Kishore Ramineni,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Hélène Solhi,
• Rémy Le Guevel,
• Chada Raji Reddy,
• Frédéric Justaud and
• René Grée

Beilstein J. Org. Chem. 2024, 20, 2592–2598, doi:10.3762/bjoc.20.218

• better accuracy on small coupling constants, resolution in 1H NMR was enhanced using Traficante. All compounds were purified by flash column chromatography on silca gel unless otherwise noted. Melting points were obtained using an Electrothermal IA9200 series digital apparatus with thin-wall glass tube

• used to hold mp samples for capillary mp determination. FTIR spectra were recorded on a Bruker Alpha apparatus with spectra further analysed with spectragryph 1.2.4 version. The absorption bands were reported in cm−1. High-resolution mass spectra were recorded in the Centre Régional de Mesures

Base-promoted cascade recyclization of allomaltol derivatives containing an amide fragment into substituted 3-(1-hydroxyethylidene)tetronic acids

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

Beilstein J. Org. Chem. 2024, 20, 2585–2591, doi:10.3762/bjoc.20.217

• formation of various unidentified byproducts. The obtained tetronic acids 4 are solid crystalline compounds, whose structure was proved by 1H, 13C NMR spectroscopy and high-resolution mass spectrometry. The 1H NMR spectra of the synthesized products contain characteristic signals of protons of the methyl

• solvent signals (DMSO-d6: 2.50 ppm (1H NMR) and 39.52 ppm (13C NMR)). High-resolution mass spectra (HRMS) were obtained on a Bruker micrOTOF II instrument using electrospray ionization (ESI). The melting points were determined on a Kofler hot stage apparatus. A magnetic stirrer IKA C-MAG HS 7 was used for

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• for the resolution of chiral amines [28]. However, it was not until 2004 that they were recognised as efficient chiral Brønsted acid organocatalysts for asymmetric Mannich reactions [29]. Malkov and co-workers revealed [30] that (R)-TRIP can act as a very efficient catalyst for the kinetic resolution

• -substituted aldimines. This was later addressed by the same researchers [15], who developed an organocatalytic kinetic resolution of secondary boronates to furnish bench-stable homochiral (S)-35. The latter were then employed in the asymmetric allylation of in situ-formed primary aldimines 37, leading

• resolution of chiral secondary allylboronates 35. In late 2020, an important method for synthesising enantiopure terminal (E)-trifluoromethyl homoallylic amines 44 was described by Szabó and co-workers (Scheme 9) [31]. This methodology is based on the use of enantiopure α-trifluoromethylallylboronic acids 43

Tandem diazotization/cyclization approach for the synthesis of a fused 1,2,3-triazinone-furazan/furoxan heterocyclic system

• Yuri A. Sidunets,
• Valeriya G. Melekhina and
• Leonid L. Fershtat

Beilstein J. Org. Chem. 2024, 20, 2342–2348, doi:10.3762/bjoc.20.200

• , indicating that the developed tandem protocol does not depend on the presence of the N-oxide moiety in the parent heterocycle. All synthesized triazinones 1 and 7 were fully characterized by IR, 1H and 13C NMR spectroscopy, and high-resolution mass spectrometry. The structure of compounds 1b and 7h was

Improved deconvolution of natural products’ protein targets using diagnostic ions from chemical proteomics linkers

• Andreas Wiest and
• Pavel Kielkowski

Beilstein J. Org. Chem. 2024, 20, 2323–2341, doi:10.3762/bjoc.20.199

• sufficient resolution and depth [52]. In general, cleavable linkers can be divided into two main groups based on the cleavage mechanism, which can be either enzymatic or chemical. The advantage of cleavable linkers is the possibility to combine stringent enrichment, ensured by the biotin–streptavidin complex