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

• -yl)-1H,3H-benzo[de]isochromene-1,3-dione (2) with good yield (79%, Figures S1–S6 in Supporting Information File 1) after purification through recrystallization from ethanol [36]. Compound 2 was used as the precursor for the synthesis of the C6-/C3-, and C0-spacer building blocks 3, 4, and 5. To

• (C0-Nap, 5) was obtained from compound 2 and ʟ-isoleucine. The products were washed with 1 M HCl and brine and did not require further purification. The naphthalene imides 3, 4, and 5 were obtained with good yields (87–99%) and in high purities (90–95%) as characterized by liquid chromatography–mass

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

• using a sodium tungstate/hydrogen peroxide system. Attempted purification led to decomposition; therefore, crude 6a and 6b were used directly in the next step. It is known that the reaction of sterically hindered nitrones may lead to metalation or deoxygenation of the alkylnitrone group instead of

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

• readily available CO2, this method delivers carboxylated SiR derivatives in 60–93% yields while avoiding the use of t-BuLi, toxic CO, and expensive palladium catalysts. In addition, the crude carboxylation mixtures can be directly subjected to amide coupling without chromatographic purification, enabling

• ethyl acetate and concentrated before being directly subjected to amide coupling without chromatographic purification. To demonstrate the utility of this strategy for probe construction, we selected three representative SiR scaffolds 1a–c, which were widely used in super-resolution imaging, for direct

• carboxylation mixtures can be directly advanced to amide coupling without chromatographic purification, allowing streamlined one-pot construction of functionalized SiR probes. Using this approach, several high-performance probes were readily prepared and successfully applied to long-term live-cell super

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

• mass intensity (PMI). Reagents should be near-stoichiometric, purification steps minimal, and catalysts effective in substoichiometric quantities. Compatibility with one-pot system and automation, such as flow chemistry and robotic synthesis, further enhance scalability. Existing tools and techniques

• sortase A-protein Z system has limited site specificity; it also requires equimolar enzyme-to-antibody ratios and additional purification steps. MTG, similarly, requires near-stoichiometric enzyme to function, restricting scalability; this enzyme is also produced as a zymogen and requires activation post

• -purification, complicating the engineering workflow. PGA optimisation benefited from the simplicity of insulin, which contains only three primary amines whose labelling can be readily resolved by UPLC, but such strategies become impractical for larger, lysine-rich proteins. For a broader overview, Zhu et al

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

• condensation using TiCl4 and pyridine, is cheaper, easier to apply, and the pure target product simply precipitated from the reaction mixture instead of extraction and purification by column chromatography. Di(pyridin-2-yl)methylene)-9H-diazafluorenes Furthermore, since ketones are generally considered to be

• additional purification. Reaction mixtures were monitored by TLC using Macherey-Nagel pre-coated TLC-sheets Alugram Xtra SIL G/UV254. For column chromatography Macherey-Nagel Kieselgel 60 was used. NMR spectra of products were recorded with Bruker AV 300, Bruker AV 400, and Bruker DRX 500 spectrometers in

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

• -osaka, Osaka 577-0056, Japan 10.3762/bjoc.22.61 Abstract E-Selective bromination for diphenylacetylene was established by using the combination of NBS and FeBr3 in CH2Cl2. In addition, easy purification and separation from the crude product were found. When the crude product was treated with heptane

• , the E isomer could be recovered as a solid material by utilizing the difference in solubility. On the other hand, the Z isomer could be removed by filtration while remaining in solution. Keywords: bromination; diarylacetylenes; green chemistry; purification and separation; stereoselective reaction

• interested in the selective synthesis of the E isomer of 1,2-dibromo-1,2-diphenylethylene, together with simple purification and separation toward process chemistry, because the compound is an attractive synthetic intermediate for further transformations. During the course of our studies, we have found that

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

• ), which enabled the absolute configuration of 3 to be assigned as 7S,8R,7'S,8'R. Moreover, this is the first report of a crystal structure of (+)-eudesmin (3). In 2015, Lu et al. reported the purification and full characterization of both enantiomers of eudesmin from Acorus tatarinowii, along with the X

• (+)-pinoresinol (2, 113.5 mg, tR 41−42 min), which was preadsorbed to C18-bonded silica (≈1 g), packed into a guard cartridge, and subjected to semipreparative C18 HPLC purification. A linear gradient from 40% MeOH (0.1% TFA)/60% H2O (0.1% TFA) to 100% MeOH (0.1% TFA) over 50 min, followed by isocratic conditions

• (3.59) nm; ECD (MeOH) λext (Δε) 208 (+6.25), 256 (−0.08), 282 (+0.26) nm; see Supporting Information File 1 for 1H and 13C NMR data in CDCl3; LRESIMS m/z: [M + Na]+ 381, [M − H]− 357; HRESIMS m/z: [M + Na]+ calcd for C20H22NaO6, 381.1308; found, 381.1307. Preparation and purification of semisynthetic

Synthesis of depressin, cryptomeridiol and 4-epi-cryptomeridiol enabled by a terpenoid chiral pool-producing platform

• Yao Kong,
• Tao Wang,
• Chen Wang,
• Pengcheng Zhang,
• Yuanning Liu,
• Kaibiao Wang,
• Fen Liu,
• Hongli Jia and
• Zhengren Xu

Beilstein J. Org. Chem. 2026, 22, 683–690, doi:10.3762/bjoc.22.53

• chlorooxoacetate to give 14a/b in 84% yield, which were subjected to the radical deoxygenation conditions (AIBN, n-Bu3SnH) for 13-hydroxy removal, affording two deoxygenated products that were difficult to be separated from each other. Without further purification, the obtained mixture was treated with tetra-n

• -butylammonium fluoride (TBAF) for TBS ether removal, followed by DMP for hydroxy group oxidation, delivering the desired product 1 in 29% overall yield in three steps from 14a/b, together with a double bond-isomerized product 15 in 39% overall yield after HPLC purification. The configuration of C12–C13 double

• conditions directly without further purification, affording cryptomeridiol (2) in 31% yield and 4-epi-cryptomeridiol (3) in 20% yield, respectively, in two steps from the expanded chiral pool germacrene A (5) produced by the engineered strain XT02019 harboring the IU pathway. The two diastereomers 2 and 3

Photoorganocatalytic trifluoromethylation of (het)arenes in green conditions

• Egor N. Boronin,
• Svetlana E. Kaurkina,
• Milena M. Svetlakova,
• Anton S. Bolshakov,
• Maxim V. Arsenyev,
• Vasilii F. Otvagin,
• Alexey Yu. Fedorov,
• Timothy Noël and
• Alexander V. Nyuchev

Beilstein J. Org. Chem. 2026, 22, 662–671, doi:10.3762/bjoc.22.50

• gases, which necessitate rigorous purification of the target products, particularly in the case of APIs. During the last 15 years, several strategies for efficient trifluoromethylation employing relatively inexpensive CF3 sources have been reported. These methodologies are based on UV-driven [7], metal

Towards the targeted protein degradation of CK2: design and synthesis of CAM4066-based PROTACs

• Sophie Day-Riley,
• Sona Krajcovicova,
• Aryaman Raj Sokhal,
• Jan L. Venne,
• Paul Brear,
• Marko Hyvönen,
• Benjamin C. Whitehurst,
• Jason S. Carroll and
• David R. Spring

Beilstein J. Org. Chem. 2026, 22, 611–619, doi:10.3762/bjoc.22.47

• construction. The synthesis of the ATP-site binder began with the alkylation of commercially available methyl 3-aminobenzoate (3) using bromoacetyl bromide. Although initial purification via silica gel chromatography led to substantial product loss, isolation by simple aqueous workup afforded the intermediate

• solubility in MeCN/H2O systems used for preparative purification; the compounds dissolved only in DMSO, explaining the diminished recovery. Nevertheless, the synthetic route successfully delivered two structurally distinct CRBN-recruiting CK2 PROTACs. All synthesised PROTACs 23–26, 28, and 29 were evaluated

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

• . 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

• 5 (CAS: 59582-20-6) [20] as a beige colored viscous oil, which was used without further purification. HRESIMS m/z: [M + H]+ calcd. for C18H23O4, 303.1591; found, 303.1596. 1H NMR data in CDCl3 (δ ppm) 1.43 (s, 3H, 2-CH3), 1.56 (s, 3H, 4’-CH3), 1.67 (s, 3H, 4’-CH3), 1.70/1.85 (m, 2H, H-2’), 2.10/2.15

Modern synthetic pathways towards eribulin and its subunits

• Sebastian Dominik Graf

Beilstein J. Org. Chem. 2026, 22, 495–526, doi:10.3762/bjoc.22.37

• -workers assembled 276 via simple ring opening of 275`s oxetane moiety and no cooling and intermediate purification were necessary. These practical improvements are particularly important for the large-scale synthesis of 1. Furthermore, every step up to 292 was carried out in kg amounts using only

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

• diffractometer. Nuclear magnetic resonance spectra were recorded on a JEOL ECX400 spectrometer. Glutaminase assays were measured on a Tecan Infinite M nano spectrophotometer. Reagents and solvents for chemical synthesis were used without additional purification. Chemical synthesis 3-Bromo-4

• employed for the final data presentation and structure plots [35]. The crystal data have been deposited in the Cambridge Crystallographic Data Centre, deposition number CCDC 2426481. Enzymatic assay Expression and purification of the GAC isoform of GLS1 Overnight cultures of BL21(DE3) strains carrying GAC

A facile and practical method for the synthesis of trans-(±)-taxifolin and its derivatives via Darzens reaction

• Bo Peng,
• Panpan Yang,
• Maaz Khan,
• Xiaotong Lin,
• Jiang Wu,
• Peng Fu and
• Qingqing Wu

Beilstein J. Org. Chem. 2026, 22, 443–450, doi:10.3762/bjoc.22.31

• [6] (Figure 1). Taxifolin can be obtained by extraction from natural plants [7][8][9], however, this is not economically viable due to the complicated extraction and purification process and low natural abundance of taxifolin. Enzymatic synthesis [10][11][12][13][14] is another method employed to

• purification was required after post-treatment. The formed silyl enol ether was then reacted with NBS (1.1 equiv) in a mixed solvent of THF and PBS buffer solution (pH 7.2) to give compound 2 with a total yield of 91% over the successive two steps. Darzens reaction of compound 2 (10.05 g) with benzaldehyde 3a

• (1.2 equiv) was performed in CH3CN, using t-BuOLi (1.2 equiv) as base in the presence of a catalytic amount of ZnCl2. Due to the high efficiency of the reaction, no purification of product (±)-4a by column chromatography was necessary after post-treatment and the product could be directly used in the

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

• carried out under a nitrogen atmosphere using standard Schlenk line methods. Reagents and solvents were obtained from GK Life Sciences Pvt. Ltd. and used without further purification unless otherwise stated. Thin-layer chromatography (TLC) was performed on silica-gel-coated aluminium sheets (silica gel 60

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

• all cases, p-aminocalix[4]arenes were obtained as the readily cleavable tert-butoxycarbonyl (Boc) derivatives, which was crucial for certain transformation and purification steps. To confirm the functionalization capabilities of the five obtained multifunctional calixarenes, they were reacted with

Dialkylaminoalkylation of β-ketosulfones via ring-opening of 3-sulfonylpyrrolidines

• Evgeny M. Buev,
• Alexander V. Pavlushin,
• Vladimir S. Moshkin and
• Vyacheslav Y. Sosnovskikh

Beilstein J. Org. Chem. 2026, 22, 383–389, doi:10.3762/bjoc.22.26

• by adding the alkyl halide directly to the cooled reaction mixture of the formed pyrrolidine without its isolation and purification, that provided higher yields of the quaternary compounds 3 rather than step by step approach. Further, we focused our attention on the search for the reaction conditions

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

• products were also obtained via the four-component reaction using non-nucleophilic acetonitrile as solvent. However, this method requires subsequent purification by preparative chromatography, and, as noted, pyranoquinolines 14a–c readily undergo alcoholysis on silica columns with methanol-containing

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

• esters could be slightly improved by using a catalytic amount of 1-butylimidazole; however, in the present work, a catalyst was not employed to simplify the purification step. The reaction temperature in this process should have been set to 230 °C. However, at this temperature, a burnt black material was

• recovery of 4.2% based on the total P analysis data. Considering the losses that occurred during the purification steps, these results were consistent with the fact that 100 g of rice bran contained approximately 6 g of phytic acid [1][2][3]. Subsequently, the isolated phytate was desalted using a cation

• ). The residue was washed with methanol and dried under vacuum overnight. Finally, 2.52 g of the crude sodium phytate was obtained as a white solid. Purification of extracted phytic acid Well-conditioned DOWEX 50W × 2 100–200 mesh (H) cation exchange resin (Dow Chemical Co., Midland, MI, USA) (60 mL) was

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

• shaker (180 rpm) at 27 °C for 7 days using a malt extract-based production medium. Harvested mycelia (1.0 L) were extracted with acetone and ethyl acetate, and purification was guided by antibacterial activity against VRE. The crude extract (922 mg) was subjected to ODS column chromatography followed by

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

• aqueous Na2CO3. The layers were separated, the organic phase collected, and the aqueous phase was further extracted with dichloromethane (3 × 25 mL). The combined organic phase was dried over anhydrous Na2SO4, filtered, evaporated in vacuo, and deposited on Celite. Purification by automated flash column

A new synthesis of Tyrian purple (6,6’-dibromoindigo) and its corresponding sulfonate salts

• Holly Helmers,
• Mark Horton,
• Julie Concepcion,
• Jeffrey Bjorklund and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2026, 22, 167–174, doi:10.3762/bjoc.22.10

• advantages of inexpensive starting reagents, operationally simple reactions, and minimal purification of intermediates. Moreover, this work reports the successful sulfonation of 6,6’-dibromoindigo, producing water-soluble derivatives of this historically relevant dye. Keywords: 6,6’-dibromoindigo; dye

• methodology of Keinan et al. [12], compound 5 was nitrated with fuming nitric acid in a mixture of glacial acetic acid and sulfuric acid. As shown in Scheme 3, this reaction yielded a mixture of 3 and 4-bromo-3-nitrotoluene (7) in a ≈3:1 ratio. Purification via column chromatography was successful in removing

• addition of 1.2 equivalents of triethylamine mediated the formation of 4 in moderate yield, as shown in Scheme 5B (57% isolated, 67% based on NMR). The crude product was sufficiently pure (84 wt % by quantitative NMR) to carry on without purification, but further purification was possible by

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

• optoelectronic applications. Experimental General information All reagents and solvents were of commercial reagent grade and used without further purification. Dichloromethane for spectroscopy was purchased from FUJIFILM Wako Pure Chemical Corporation. All compounds were identified by 1H , 13C NMR and ESI-MS. 1H