Synthesis and acaricidal activity against Varroa destructor of α- and γ-costic acid dimers

• Alessandro Santarsiere,
• Ernesto Santoro,
• Maria Letizia Ciavatta,
• Marianna Carbone,
• Sonia Ganassi,
• Cosimo Tedino,
• Antonio De Cristofaro,
• Antonio Evidente and
• Stefano Superchi

Beilstein J. Org. Chem. 2026, 22, 1088–1096, doi:10.3762/bjoc.22.87

• otherwise stated. Flash chromatography was performed using 60–200 mesh silica gel. 1H NMR and 13C NMR spectra were recorded on Varian (Palo Alto, CA, USA) 400 MHz and 500 MHz and 100 MHz and 125 MHz spectrometers, respectively, at ambient temperature in CDCl3, unless otherwise noted, using the same solvent

• successively added. After stirring the solution for 5 minutes at 0 °C, ethylene glycol (1.0 equiv) was added to the resulting whitish suspension and the reaction mixture was allowed to warm to room temperature overnight. The white precipitate was removed by filtration and rinsed with CH2Cl2. The solvent was

• room temperature and stirred overnight. The white precipitate was removed by filtration and rinsed with CH2Cl2. The solvent was then removed under reduced pressure. The crude residue was purified by column chromatography (eluent: petroleum ether/EtOAc 8:2) to afford α-costic acid diester 6 (79%). 1H

Synthesis of functionalized, 13-alkyl-substituted coralyne derivatives and investigation of their interactions with duplex and abasic site-containing DNA

• Laurin Beckmann,
• Jason Lennard Kunze,
• Hannah Karola Strunk,
• Maurice Michel and
• Heiko Ihmels

Beilstein J. Org. Chem. 2026, 22, 1057–1066, doi:10.3762/bjoc.22.84

• are referenced relative to tetramethyl silane (TMS, δ = 0.00 ppm), hexafluorobenzene (C6F6 δF = -164.9 ppm), or residual solvent signals (DMSO-d6: δH = 2.50 ppm, δC = 39.52 ppm); MestReNova 12.0.4-22023. MS (ESI): Finnigan LCQ Deca (U = 6 kV, working gas: argon, capillary temperature: 200 °C

• , auxiliary gas: nitrogen); analysis with FreeStyle 1.3 SP2. HRMS (ESI): Thermo Fischer Exactive (U = 2.7–3.5 kV, sheath gas: argon, capillary temperature 300 °C). Elemental analysis: HEKAtech EUROEA combustion analyzer (in-house). Melting points: Büchi 545 (Büchi, Flawil, CH); uncorrected. Absorption

• : Enzymes (UNG, APE1, NEIL1, NTHL1, NEIL3, OGG1) and mutants were produced as reported previously [59]. General methods The reaction mixtures were stirred with a magnetic stirrer equipped with a stirring bar. The average room temperature (rt) was 22–24 °C. If not stated otherwise, operations were conducted

One-pot four-component sequential synthesis of S-alkyl dithiocarbamates using lipase as a biocatalyst

• Mansour Shahedi,
• Pargol Tahmasebi pour and
• Zohreh Habibi

Beilstein J. Org. Chem. 2026, 22, 1048–1056, doi:10.3762/bjoc.22.83

• , and the reaction was continued at 25 °C. Monitoring the reaction via TLC revealed a significant reduction in the amount of side product, with the desired product 6b obtained at a 51% yield after 12 h (Table 1, entry 2). Based on this result, 25 °C was determined to be the optimal temperature for the

Synthesis of novel 1,2,4-oxadiazole-isoxazoline hybrids and their in silico potential with adenosine receptors

• Pshtiwan S. Mohammed,
• Mohammed K. S. Dalo,
• Onur C. Yazıcı,
• Muhammet Yildirim and
• Akın Sağırlı

Beilstein J. Org. Chem. 2026, 22, 1033–1047, doi:10.3762/bjoc.22.82

•  3, Table 1). The low yield of 6i is likely attributed to the amidoxime formation step, where the electron-rich dimethylamino group in benzonitrile 3i did not sufficiently facilitate amidoxime formation. Moreover, the final cyclization step, conducted under basic conditions at elevated temperature

•  2). As a result of these optimization studies, the target compound 7a was obtained in moderate yield under the optimized conditions using 1.0 equivalent of 2e, 1.5 equivalents of 6d, 15 equivalents of sodium hypochlorite, and 1.0 equivalent of triethylamine in dichloromethane at room temperature

Semisynthesis, characterisation, and antibacterial evaluation of a novel lecanoric acid-derived amide library

• Ethan D. Abbott,
• Sasha Hayes,
• Jonathan M. White,
• Bernd H. A. Rehm and
• Rohan A. Davis

Beilstein J. Org. Chem. 2026, 22, 1023–1032, doi:10.3762/bjoc.22.81

• commercially available primary amines, several trial amidation reactions were undertaken. This involved scaffold 1 (20 mg) being reacted with the abundant and moderately volatile isopentylamine (bp 95–97 °C) at three different reaction times (i.e., 1 h, 2 h, and 4 h), with temperature and stirring conditions

• under UV light at 254 nm. The raw lichen material was extracted with solvents at 200 rpm using an IKA™ KS 125 Basic® orbital shaker operating at room temperature. Solvents were removed from lichen-derived crude extracts with a Büchi R-300 rotary evaporator. A GeneVac HT-4X centrifugal evaporator was

• private property in Holland Park, Queensland, Australia on the 5th of April 2023. Patrick McCarthy and Jack Elix performed the taxonomic identification of the lichen. The freshly collected lichen was air-dried at room temperature for one month prior to the extraction and isolation chemistry. A voucher

Z-Selective semihydrogenation of alkynes via Ni/Lewis acid synergistic catalyzed system using DMF as hydrogen source and solvent

• Lei Kang,
• Haifeng Gao and
• Luo Yang

Beilstein J. Org. Chem. 2026, 22, 1004–1012, doi:10.3762/bjoc.22.79

• temperature was also critical. A significant drop in yield was observed at 130 °C (Table 3, entry 18), and although 140 °C provided an 88% yield (entry 19), optimal conversion required 150 °C (entry 2). The reaction time was optimized to 24 hours; shorter (12 h, Table 3, entry 20) or moderately shorter (18 h

• the reaction temperature while maintaining a fixed reaction time of 24 h. The results are summarized in Table 4. At 130 °C, the GC yield of styrene (4a) was only 30% (Table 4, entry 1). Raising the temperature to 135 °C improved the yield to 58% (Table 4, entry 2) and the optimal performance was

• observed at 140 °C, providing 4a in 70% GC yield (64% isolated yield, entry 3). Further increases to 145 °C or 150 °C led to diminished yields of 67% and 51%, respectively (Table 4, entries 4–5). These results suggest that the reduction of terminal alkynes is more temperature-sensitive than that of

Rh(III)-catalyzed chelation-assisted C–H activation/annulation of 2-arylimidazolines with cyclic diazo-1,3-dicarbonyl compounds: a novel approach to tetracyclic annulated derivatives of 2,3-dihydroimidazo[2,1-a]isoquinoline

• Ivan Lyutin,
• Grigory Kantin,
• Olga Bakulina and
• Dmitry Dar'in

Beilstein J. Org. Chem. 2026, 22, 997–1003, doi:10.3762/bjoc.22.78

• reaction time or changing the temperature did not improve the result as well (Table 1, entries 8–11). The type of solvent was also found to be critical for this reaction – using dichloroethane allowed preparation of compound 4a in a lower, but still noticeable, yield of 60%, while no target product was

The role of spacer length and flexibility in peptide self-assembly

• Julian Link,
• Albin Lahu,
• Manfred Wagner,
• Tanja Weil and
• David Y. W. Ng

Beilstein J. Org. Chem. 2026, 22, 986–996, doi:10.3762/bjoc.22.77

•  1A) [40]. The peptide stock solutions prepared in TFE (10 mM) were diluted in PBS (50 mM, pH 7.4) to obtain 100 µM peptide samples (1% TFE). The mixtures were then incubated at room temperature for 24 h to promote self-assembly. Corresponding samples in methanol (1% TFE) were prepared in parallel and

• swollen in DMF (15 mL) at room temperature for one hour before transferring it into the peptide synthesizer. In the peptide synthesizer, DMF was removed through the draining process and DMF (3.5 mL) was added prior to the coupling. Prior to every coupling, the Fmoc-protecting group was cleaved by one

• deprotection step using a solution of 8% piperidine (DMF, 2.1 mL) for 80 s at 110 °C. The amino acids (0.5 M in DMF, 1.0 mL), DIC (0.75 M in DMF, 1.0 mL) and Oxyma Pure (0.26 M in DMF, 1.5 mL) were added to the resin and the solution was heated to 105 °C for 60 s and held at that temperature for 30 s. The

Synthesis of sterically shielded piperidine nitroxides via acid-catalyzed heterocyclization of β-aminoketone derivatives with ketones

• Mark M. Gulman,
• Yurii I. Glazachev and
• Sergey A. Dobrynin

Beilstein J. Org. Chem. 2026, 22, 948–954, doi:10.3762/bjoc.22.74

• proteins by the PELDOR method at room temperature [2]. Piperidine nitroxyl biradicals form the basis of the most efficient commercial agents for dynamic nuclear polarization (DNP) in NMR studies of biomolecules and solid samples [3]. They are also employed as contrast agents for magnetic resonance imaging

Recent advances in copper-catalyzed direct hydroamination of alkenes with (hetero)aromatic amines

• Hyejeong Lee and
• Yunmi Lee

Beilstein J. Org. Chem. 2026, 22, 925–947, doi:10.3762/bjoc.22.73

• ) were subsequently evaluated by adding aniline to activated olefins (Scheme 3) [35][36]. Using 5 mol % of the copper–amido catalyst at room temperature, the α,β-unsaturated substrates including acrylonitrile, methyl vinyl ketone, methyl acrylate, and cyclic enones were converted to the corresponding β

• triflate species serving as Lewis acidic metal salts (Scheme 8, conditions B) [44]. Coordination of the Lewis acid to these electron-deficient alkenes substantially enhanced their reactivity toward nucleophilic attack, enabling the efficient formation of aza-Michael adducts 17 at ambient temperature. The

• that under conditions A, copper nanoparticles (CuNPs, 1.2 mol %) efficiently promoted the aza-Michael addition of anilines to activated alkenes at room temperature (Scheme 11a) [49]. In this system, the nanoparticulate copper surface acts as a Lewis acid to activate the Michael acceptor 33 through

A practical CO₂-mediated synthesis of 5,6-carboxylated silicon-rhodamines for targeted probe development

• Dongjie Hou,
• Shaowei Wu,
• Ning Xu,
• Pengjun Bao,
• Wenhao Jia,
• Qinglong Qiao and
• Zhaochao Xu

Beilstein J. Org. Chem. 2026, 22, 915–924, doi:10.3762/bjoc.22.72

• 1a–c were treated with 2.5 equiv of n-BuLi in anhydrous THF at −78 °C under a nitrogen atmosphere to generate the corresponding aryllithium intermediates, followed by introduction of CO2 via a balloon. The reaction mixture was then allowed to warm to room temperature and stirred overnight to ensure

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

• catalyst (Table 1, entry 7). When the reaction temperature was reduced to 110 °C, 120 °C, or 130 °C, product 3aa was obtained in lower yields in all cases compared with entry 7 (Table 1, entries 8–10). Using o-xylene as the solvent gave results similar to those obtained with DMF (Table 1, entry 11

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

• MeCN) for the reaction of azirine 1a and benzaldehyde (2c, Scheme 3). Calculations indicate that condensation and subsequent cyclization should readily occur at room temperature, with only the diastereoisomer (1RR,3SR,6RR)-Phe-C (with the Ph group from benzaldehyde in the equatorial position

Chiral cyclopropenimine-catalyzed enantioselective Michael reactions of phenol and benzofuran-derived α,β-unsaturated pyrazolamides with benzophenone-imine of glycine esters

• Ya Bai,
• Xue-Ying Wang,
• Si-Kai Zhu,
• Yan-Ting Shen,
• Sheng-Yong Zhang and
• Ping-An Wang

Beilstein J. Org. Chem. 2026, 22, 888–896, doi:10.3762/bjoc.22.69

• the catalytic effect of CSB-1. Based on these results, the optimal reaction conditions are listed in Table 1, entry 1. The reactions between 2 and 5 were carried out in EtOAc by using 20 mol % of CSB-1 as a catalyst at room temperature. With the optimal conditions in hand, the asymmetric Michael

Diastereodivergent electrophilic trapping of α-boryl lithium derivatives

• Tereza Pavlíčková,
• Noam Orbach and
• Ilan Marek

Beilstein J. Org. Chem. 2026, 22, 882–887, doi:10.3762/bjoc.22.68

• moderate yields with good diastereoselectivity. Reaction with cyclohexanone led to partial elimination, which proceeded to completion upon warming the reaction mixture to room temperature, affording the bora-Wittig product 6j in moderate yield [39]. Furthermore, an intramolecular reaction was investigated

Site-specific labelling of native peptides and proteins: chemical and enzymatic strategies

• Antonio Angelastro,
• Jonathan Bargh,
• Subhajit Guria,
• Victor Laserna and
• Louis Luk

Beilstein J. Org. Chem. 2026, 22, 857–881, doi:10.3762/bjoc.22.67

• modification. The chemical or enzymatic steps are generally mild (room temperature, aqueous buffer) yet highly specific. However, the main limitation is that only glycosylated proteins (especially IgGs) can be targeted. Intrinsic glycan heterogeneity can also lead to incomplete functionalisation. Biological

The trans-influence in gold chemistry from a catalytic perspective

• Manfred Bochmann

Beilstein J. Org. Chem. 2026, 22, 838–856, doi:10.3762/bjoc.22.66

• (II) congener, K[PtCl3(ethylene)] [28], as well as the first examples of gold(III) alkyne [29], CO [30], hydride [31] and σ-complexes [32] (Scheme 3). The olefin complexes were isolated as microcrystalline powders which as dry solids are fairly stable in air at room temperature. The olefin bonding is

• ^C^N complex 12 (H trans to C) is stable in THF solution at −20 °C but decomposes at room temperature. This instability of 12 may in part also be due to the tendency of the pyridine arm to dissociate; for example, on addition of LiHBEt3 the pyridine is displaced to give the dihydrido complex Li[(N–C

• ^C)AuH2] [50]. Goldberg’s complex 13, on the other hand, which is stabilised by two strongly donating P(t-Bu)2 moieties, is stable at room temperature and could be crystallographically characterised [53]. A gold hydride of type 12 has been postulated as an intermediate in the thermal decomposition of

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

• , frequently employed as a model system to study the activity of catechol oxidase and tyrosinase. Although hydrogen peroxide is a strong oxidant, its reaction with 3,5-DTBC is often slow at room temperature in the absence of a catalyst, typically requiring metal ions such as Cu2+, Fe3+, or Co2+ [43]. Moreover

• {1H} NMR spectroscopy (Figures S1–S20), HRMS (Figures S21–S26) in Supporting Information File 1, and elemental analysis. X-ray data The X-ray suitable crystals of 1a, 4a–7a were grown by slow recrystallization of the compounds from acetonitrile or chloroform (for 7a) solutions at room temperature. The

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

• ). Reduction of 24 with NaBH4. NaBH₄ (95 mg, 2.52 mmol, 2 equiv) was added in portions to a stirred solution of 24 (0.40 g, 1.26 mmol, 1 equiv) in MeOH (15 mL) at room temperature. The mixture was stirred for 2 h, poured onto ice, and the resulting yellow precipitate of 25 was collected by filtration (295 mg

Knoevenagel condensation of 4,5- and 1,8-diazafluorenes

• Darya S. Cheshkina,
• Christina S. Becker,
• Alina A. Sonina and
• Maxim S. Kazantsev

Beilstein J. Org. Chem. 2026, 22, 803–812, doi:10.3762/bjoc.22.62

• ), ammonium acetate (60.5 mg, 0.79 mmol), and aldehyde (0.20 mmol) in glacial acetic acid (5 mL) was heated to 110 °C with stirring for 12 h. The resultant solution was cooled to room temperature and neutralized with aqueous ammonia solution (25%) to pH 6. The precipitate of a product was filtered off and

• toluene (5 mL) was heated to 110 °C with stirring for 12 h. The resultant solution was cooled to room temperature and neutralized with aqueous ammonia solution (25%) to pH 6. The precipitated compounds (see Table 1) were isolated by filtration followed by washing sequentially with portions of water

• stirred at room temperature for 2 h and then poured into water and extracted with chloroform. The extract was dried over MgSO4 and concentrated under reduced pressure. The products were purified by column chromatography on silica gel using ethyl acetate as eluent. General method (B2) for the condensation

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

• ) with NBS (N-bromosuccinimide, X equiv), FeBr3 (1.0 equiv), n-Bu4NBr (Y equiv), and TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl free radical, Z equiv) in solvent (2 mL) at the desired temperature was conducted for 23 h or 2 h. After the reaction, the typical work-up procedure was carried out and the

• 2). The use of a smaller amount of NBS (1.2 equiv) did not result in a decrease of yield, indicating that FeBr3 is thought to be one of the sources of bromine (Table 1, entry 3). To increase the chemical yield and ratio of E-2a/Z-2a/1a, various parameters such as NBS, n-Bu4NBr, TEMPO, temperature

• heated by a heating gun. After cooled to room temperature, the flask was filled with N2. FeBr3 (154.2 mg, 0.52 mmol) and NBS (N-bromosuccinimide, 196.0 mg, 1.10 mmol) were added to the glass flask. Then, CH2Cl2 (dry, 2.0 mL) and 1,2-diphenylacetylene (1a, 89.4 mg, 0.502 mmol) were added and the mixture

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

• to a photoresponsive polymeric material imparting unique properties. A switchable glass-transition temperature (Tg) and thus resulting self-healing ability is a typical example [6]. As reported by Yu et al. [7], the different Tg of E and Z-isomers can lead to so called surface photofluidization due

• fluorescence intensity linearly dependent on the temperature [19][20]. Priimagi et al. reported thermal sensors based on the simple azobenzenes B1–3 by exploiting the dependence of the protonation rate on the temperature, which is accompanied by a color change [21]. Four different azobenzenes C1–4 were used as

• liquid crystalline copolymeric pendants in macromolecules capable to change their reflectance with the temperature. This feature potentially enables their usage in temperature sensing labels [22]. These representative applications clearly demonstrate a wide interest in a light-driven control over the

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

• -methyl groups cannot freely rotate past the nearby sulfone oxygen atoms. Calculations suggested a rotation barrier of 18 kcal/mol, consistent with it being insurmountable at room temperature, vs only 4 kcal/mol for the unsubstituted phenyl ring (see Supporting Information File 1). The combined results of

• sulfinates. In contrast, performing the competition experiment at room temperature gave a different product profile in which a good yield of 26 (62%) precipitated from the reaction mixture. No other products were observed in either the precipitate or the extracted filtrate from that reaction. The high

• selectivity for formation of 26 at room temperature suggests a profile that is more reflective of kinetic control, such that we can argue that 26 forms between 1 and 2 orders of magnitude more rapidly than cyclic products 1a and 1b, such that they are not detectable in the 1H NMR spectra. Further anecdotal

Synthesis of heterocycles based on azomethine ylides from α-amino acids (or amines) and carbonyl compounds

• Ekaterina V. Berezhnaya,
• Alexander I. Ponyaev,
• Vitali M. Boitsov and
• Alexander V. Stepakov

Beilstein J. Org. Chem. 2026, 22, 705–741, doi:10.3762/bjoc.22.55

• )benzylamine (92) as an azomethine ylide precursor in (3 + 2)-dipolar cycloaddition reactions with electron-deficient exo-cyclic 93 and endo-cyclic alkenes 94 (Scheme 36) [77][78][79]. To generate the azomethine ylide from reagent 92, TFA in methylene chloride at room temperature or LiF in acetonitrile with

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

• reaction using N-bromosuccinimide (NBS) in CH2Cl2 at room temperature (1 h), we produced 5 as a single enantiomer (i.e., (+)-5,5'-dibromopinoresinol). Herein, we report the full spectroscopic and spectrometric characterization of this molecule. Furthermore, analogues 6 and 7 are new semisynthetic molecules

• plates were used for TLC and analyzed under UV light at 254 and 365 nm. For large-scale studies, the plant material was extracted at room temperature using an Edwards Instrument Company Bio-line orbital shaker set to 200 rpm. All chemical reagents used throughout the experiments were purchased from Sigma

• (+)-pinoresinol derivatives 3–7 Methylation of (+)-pinoresinol (2) (+)-Pinoresinol (2, 15.8 mg, 0.044 mmol) was dissolved in MeOH/CH2Cl2 1:1 (250 μL) before (trimethylsilyl)diazomethane (2.0 M in diethyl ether, 150 μL) was added dropwise. The reaction mixture was stirred for 20 min at room temperature and then