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

• and 9b, respectively, but all attempts to separate the isomeric epoxides 9a and 9b by column chromatography or crystallization failed. Eight-membered rings are known to preferentially adopt boat-chair conformations, which minimize torsional and transannular strain [24]. To further rationalize the

• ) MHz Bruker spectrometers and are reported in δ units with SiMe4 as internal standard. HRMS spectra were obtained on a Bruker microTOF-Q or Agilent 6530 Accurate Mass Q-TOF instrument. Melting points were determined on a GallenKamp MPD 350. Column chromatography was performed on silica gel (60 mesh

• under reduced pressure. The crude product was purified by silica gel column chromatography eluting with pure hexane to give as the first fraction monoepoxide 6 (1.09 g, 8.78 mmol, 95%, a colourless oil) and as the second bisepoxide (0.07 g, 0.5 mmol, 5%, a white solid). The spectroscopic data are in

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

• , Germany). High resolution mass spectra were recorded on a FTHRMS-Orbitrap mass spectrometer (Thermo-Finnigan, Waltham, MA, USA). Merck MN silica gel 60 M (0.04–0.063 mm) was used as stationary phase for column chromatography. TLC was performed on silica gel 60 F254 plates with UV-detection. Solvents and

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

• layer was separated and dried with Na2SO4. The drying agent was filtered off, the solvent was removed under reduced pressure, and the crude product was purified by column chromatography (SiO2, n-hexane, Rf = 0.44) and recrystallization from n-pentane. The product was obtained as colorless cubes (84.0 mg

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

• subsequent oxy-Michael reaction. The mixture (137 + 138) was treated with p-TsOH leading to alcohols 139 and 140, which were separated via chromatography. From 140, Bn-deprotection of the primary, followed by Bn-protection of the secondary alcohol unit afforded 141 in 52% yield. Eventually, the ester motif

• allylated with crotyl bromide according to a procedure from Loh and co-workers [92]. The diastereomeric mixture thus obtained was separated via chromatography and (R)-151 was protected using BnBr. After hydroboration–oxidation and DMP-oxidation to the respective aldehyde, Ohira–Bestman reaction was applied

• esterification with EtI were conducted to form 318. TBDPS-protection and reduction yielded alcohol 319 in 58%, which was further oxidized to the respective aldehyde and olefinated leading to a 4:1 (Z/E) mixture of 320. The isomers were separated via chromatography, then, (Z)-320 was deprotected under acidic

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

• using thin-layer chromatography, with the appearance of the characteristic red spot upon treatment with FeCl3 confirming the presence of the hydroxamic acid functionality. Moreover, the formation of the tetra-hydroxamic acid product was confirmed by 1H NMR spectroscopy in deuterated DMSO, as evidenced

Synthesis of a HDAC inhibitor–nanogold probe for cryo-EM visualization in class I HDAC co-repressor complexes

• Wiktoria A. Pytel,
• John W. R. Schwabe and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2026, 22, 480–485, doi:10.3762/bjoc.22.35

• to its corresponding NHS ester 8 and residual starting material was removed by column chromatography. The Boc-protecting group was removed under anhydrous conditions in good yield and the structure of 9 was confirmed by NMR spectroscopy. Compound 9 was maintained as the TFA salt for the final step

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

• (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

• 1.5 h. Thin-layer chromatography (TLC) was used to track the reaction progress. Upon completion of the reaction, ice-cold water was used to quench the reaction mixture, and the mixture was extracted with ethyl acetate. After two water and brine washes, the organic layer was dried over anhydrous

• magnesium sulfate (MgSO₄) and concentrated under low pressure. Column chromatography was performed to purify the crude product using a solvent ratio of petroleum ether to ethyl acetate (85:15), which yielded a yellow solid. Yield: (295 mg, 54%). mp: 156–157 °C; 1H NMR (400 MHz, CDCl3) δ 8.62 (d, J = 7.3 Hz

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

• copper complex (although an extraction procedure for complex destruction using Na2S2O3 was applied), which was difficult to separate from the relatively polar free calixarene 37 using column chromatography. In line with this, when toluene-soluble CuI·P(OEt)3 was used as a catalyst (in this case heating

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

• liquid chromatography–mass spectrometry. Their anticancer activity was assessed against human cancer cell as well as non-cancer cell lines. Three compounds, 1, 3, and 9, were the most cytotoxic to HeLa cells (IC50 = 6.13 ± 1.95, 13.99 ± 1.80 and 49.92 ± 3.98 μM, respectively). However, only compounds 1

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

• extraction or column chromatography. On the other hand, upon performing the reaction with amines in acetonitrile we did not observe the formation of benzamides. Presumably, debenzoylation occurred in basic media with water traces and cesium benzoate was discarded upon work-up. The presumable mechanism of the

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

• mixture by preparative TLC or column chromatography. Notably, compounds 4a, 4e, and 4k were purified by crystallization. Detailed synthetic and isolation procedures for all compounds are provided in Supporting Information File 1. We regret to state that when forming a mixture of diastereomers, we were

• unable to isolate individual products either by chromatography or by recrystallization. The proposed reaction mechanism is shown in Scheme 5, where it can be seen that the intermediate azomethine ylide, acting as a 1,3-dipole, undergoes a [3 + 2] cycloaddition with N-substituted maleimides 3a–p. The

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

• chromatography on silica gel with a methanol-containing eluent, isolated pyranoquinoline 14 underwent alcoholysis, converting it into the corresponding methyl ester 10 at the column outlet. These observations further support the mechanistic considerations of the four-component reaction discussed earlier

• 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

• dried crude product was purified by column chromatography using a solvent mixture of dichloromethane and n-hexane in a 1:2 volume ratio. The purified product 4 was obtained as a white solid in a yield of 2.53 g (91%). Synthesis of 5-(3-(9H-carbazol-9-yl)phenyl)-2-(p-tolyl)isoindoline-1,3-dione (1) For

• sulfate (Na2SO4) to remove any traces of water. The dried solution was then filtered to remove the drying agent and concentrated under reduced pressure to remove the solvent. The resulting crude product was purified by column chromatography using a 1:2 volume ratio of dichloromethane and n-hexane. The

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

• its light-brown appearance was identical to that of the product synthesized from commercial phytic acid. High-performance liquid chromatography (HPLC) analysis results indicated that the purity of 2a derived from the extracted phytic acid was greater than 95% (Supporting Information File 1, Figure S4

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

• ethanol (Scheme 5, VII). However, under these conditions only decomposition of 4g was observed, and neither deacetylated nor hydroxylated products were isolated. Interestingly, chromatography of 4g on neutral alumina resulted in elimination of the sulfonylimine group to give compounds 5g. Therefore, the

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

• of the required imine intermediate that upon reduction yields the desired product. The free base 1 was purified on normal-phase flash column chromatography, and 1·HCl was subsequently precipitated, providing a white crystalline solid (vide infra). Characterization of 25CN-NBOH·HCl (1·HCl) in the

• (granulated, >95%) from TCI Europe N.V. (Zwijndrecht, Belgium), and molecular sieves (3 Å, Ø 3–5 mm) from BLD Pharmatech GmbH (Hamburg, Germany). Ultrapure water (18.2 MΩ·cm) was collected from a Purelab Quest (Elga LabWater, High Wycombe, UK). Thin-layer chromatography (TLC) was performed on aluminium sheets

• chromatography (Pure C-810 Flash, Büchi Labortechnik GmbH, Essen, Germany) was performed with a normal-phase silica column (25 g FlashPure EcoFlex, Büchi), employing a binary gradient from 0–100% (EtOAc/EtOH 3:1 + 2% aqueous NH3)/n-heptane. Product fractions were pooled and evaporated in vacuo, providing the

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

• 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

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

• Celite. The Celite was thoroughly washed with dichloromethane, and the combined filtrate was washed three times with saturated aqueous NH4Cl and brine. The organic layer was dried over anhydrous sodium sulfate. The crude product was purified by silica gel column chromatography using a 1:1 mixture of

• with dichloromethane three times, and the combined organic layer was washed with saturated brine. The organic layer was dried over anhydrous sodium sulfate, after drying, the solvent was removed under reduced pressure. The crude product was purified by silica gel column chromatography using a 1:1

• chromatography using a 9:1 mixture of dichloromethane and methanol as the eluent. The eluate was evaporated, and the resulting solid was washed with methanol and dried under vacuum to afford the orange solid of R-Pt (24 mg, 47%). Data for R-Pt: Orange solid; mp 280 °C (dec); HRMS (orbitrap) m/z: [M + H]+ calcd

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

• and 9b (1.3:1 dr, according to the 1H NMR spectrum) due to the axial chirality of this molecule. The mixture was easily separated by silica gel column chromatography. Each of the isomers is characterized by the trans-configuration of the nitro- and trichloromethyl groups in the cyclopropane ring (3JH

• was carried out by column chromatography on silica gel MN Kieselgel 60 Macherey-Nagel 140–270, eluent was a mixture of solvents hexane–EtOAc, 3:1. The reaction progress and purity of the obtained compounds were controlled by TLC on Silufol UV-254 plates with 3:1 hexane–EtOAc mobile phase

One-pot synthesis of ethylmaltol from maltol

• Immanuel Plangger,
• Marcel Jenny,
• Gregor Plangger and
• Thomas Magauer

Beilstein J. Org. Chem. 2025, 21, 2755–2760, doi:10.3762/bjoc.21.212

• . Subjecting maltol (2) to trimethylsilyl chloride and triethylamine furnished the corresponding silyl ether 8d in nearly quantitative yield (Table 2, entry 4). Due to the instability of the trimethylsilyl ether functionality to flash column chromatography, methylation of 8d was followed by desilylation with

• ). Purification with flash column chromatography provided analytically pure ethylmaltol (1), which, however, displayed an off-white/yellowish color. A final vacuum distillation yielded purely white ethylmaltol (1) consistent with commercial samples. The ethylmaltol (1) thus produced was analyzed by the Central

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

• layer. High-resolution ESI mass spectra (HRMS) were recorded with a Bruker micrOTOF II instrument. Silica gel 60 Merck (15–40 μm) was used for preparative column and thin-layer chromatography. Silica gel “Silpearl UV 254” was used for preparative column and thin-layer chromatography. Analytical thin

• -layer chromatography (TLC) was carried out on Merck silica gel 60 F254 and “Silufol” TLC silica gel UV-254 aluminum sheets. All reagents were purchased from Acros and Sigma-Aldrich. Solvents were purified before use, according to standard procedures. All other reagents were used without further

• ), dried over Na2SO4, and solvent removed in vacuo. Products 2a–i were isolated by column chromatography on silica gel. Procedure for gram scale electrochemical synthesis of 2f (experimental details for Scheme 3, reaction 1): In a manner analogous to one described in [87], an undivided 50 mL

Total synthesis of asperdinones B, C, D, E and terezine D

• Ravi Devarajappa and
• Stephen Hanessian

Beilstein J. Org. Chem. 2025, 21, 2730–2738, doi:10.3762/bjoc.21.210

• equivalents of H2SO4 in water to obtain a mixture of six C-prenylated tryptophans from which the 7-prenyl isomer could be isolated in 4% yield after chromatography on a 10 g scale [27]. This direct prenylation method was then adapted for the synthesis of terezine D (6), which was isolated as a pale-yellow

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

• precipitated from the reaction, which allowed it to be easily isolated and purified by crystallization from MeCN. Diastereomer 4att was obtained from the filtrate also by crystallization from MeCN. Column chromatography allowed us to isolate octahydropyrido[1,2-a]pyrimidinones 4atc, 4acc in an individual form

• 5ctt (δF 79.74 ppm). All products were individually isolated by column chromatography. Carrying out these syntheses in 1,4-dioxane in the presence of acetic acid and triethylamine increased the selectivity for the formation of octahydropyrido[1,2-a]pyrimidinones 4 in the reactions with alkyl methyl