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

• corresponding acetates 10 and 11 using AcCl in CH2Cl2. The reaction mixture was chromatographed on a silica gel column with n-hexane/ethyl acetate 85:15 as eluent to give pure acetates 10 and 11 in 57% and 35% yields, respectively. The structure of compound 10 was unambiguously determined by single crystal X

• ) 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

• , Merck). TLC was carried out on Merck 0.2 mm silica gel 60 F254 analytical aluminium plates. (1R*,8S*,Z)-9-Oxabicyclo[6.1.0]non-4-ene (6) A magnetically stirred solution of cis,cis-1,5-cyclooctadiene (5, 1.00 g, 9.24 mmol) in 50 mL dichloromethane was cooled to 0 °C. m-CPBA (2.20 g, 77%, 9.82 mmol) and

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

• extract (3 × 20 mL) yielded 76 mg (88%) of a mixture of 2-iodomelifolione A (8) and 4-iodomelifolione B (9) in a ratio of 10:1 as white solid from diethyl ether/hexane. TLC on silica gel 60 F254 plates with hexane/ethyl acetate (10+2): fR = 0.28 in relation to melifoliones fR = 0.38. HRESIMS m/z: [M + H

• ), the organic layer was dried over MgSO4, filtered and evaporated under reduced pressure. The residue was chromatographed on silica gel with hexane/ethyl acetate (5:1 to 1:1) to yield 55 mg (18%) colorless solid. TLC on silica gel 60 F254 plates with hexane/ethyl acetate (10:1): fR = 0.15 in relation to

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

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

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

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

• 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

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

• the mixture was extracted three times with dichloromethane and saturated aqueous NH4Cl. The organic layers were washed with saturated brine, then dried over anhydrous sodium sulfate. After drying the solvent was removed under reduced pressure. The crude product was then purified by silica gel column

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

Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review

• Daniel S. Müller

Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1

• ) in the presence of ZnCl₂ supported on silica gel converted ketones into the corresponding alkenyl chlorides (Scheme 19) [72]. The scope appears to be limited to aromatic ketones furnishing non-terminal alkenyl chlorides. Su and co-workers reported the synthesis of alkenyl chlorides using a

• discrepancy to product degradation during purification on neutralized silica gel (1% NEt₃) or neutral alumina. However, this hypothesis was not experimentally verified, as no control experiment involving the passage of a pure, non-volatile alkenyl chloride through the purification media was reported to assess

• gel (Scheme 60D). As mentioned in the introduction, a comprehensive account of this work has been recently reported by Hoveyda [39]. 1.9 Olefinations of ketones and aldehydes In 1961, Wittig and Schlosser reported the first synthesis of alkenyl chlorides via the classical Wittig reaction (Scheme 61A

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

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

• , electron ionization, electron energy: 70 eV, ion source temperature 200 °C; mass range 34–650 Da. The solvent was chloroform or acetone. Column chromatography was performed on silica gel 60 (70–230 mesh, particle size 0.063–0.200 mm or 230–400 mesh, particle size 0.040–0.063 mm, Merck). Commercially

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

• numbers: CCDC 2470493 (20e), CCDC 2470491 (21g), CCDC 2470492 (23a), CCDC 2470490 (25), CCDC 2470489 (26), CCDC 2472402 (27). All reagents were purchased from commercial sources and were used without further purification. Reactions were followed by analytical thin-layer chromatography on silica gel 60

• F254 (Merck 105554). Dry-column flash chromatographic purifications were performed on silica gel 60 H (Merck 107736), silica gel 60 (Merck 115111) or aluminum oxide 60 G neutral (Merck 101090) column [26]. 9-Chloro-6-methyl-2,3-dihydro[1,4]benzodioxino[6,7-c]benzo[f][1,2]thiazepin-12(6H)-one 7,7

• (100 mL), the combined organic phases were dried over Na2SO4, evaporated, and the oily residue was triturated with a little amount of acetone to afford a second crop of crude 7 (8.45 g of pale yellow solid). The two crops were purified by dry-column flash chromatography on a short silica gel column

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

• remains a major challenge due to the strong hydration of anions. Here, we report the preparation of silica gel functionalized with covalently anchored bambusuril macrocycles. In aqueous solution, this material efficiently sorbs dicyanoaurate(I), the key anion in gold mining, even in the presence of

• leading not only to improved extraction effectivity but also to enhanced selectivity [2]. Anion extractants based on functionalized polystyrene or silica gel typically incorporate calixarenes [6] and their analogues, calixpyrroles [7][8], azacalixarene derivatives [9], or expanded porphyrin-like sapphyrin

• functionalized, for instance by carboxylic moieties [13], making them available for further reactions with different substrates. We have recently presented a material (SG-BnBU) based on silica gel containing dodecabenzylbambus[6]uril (BnBU) non-covalently bound on its surface [14]. We showed that this material

Recent advances in total synthesis of illisimonin A

• Juan Huang and
• Ming Yang

Beilstein J. Org. Chem. 2025, 21, 2571–2583, doi:10.3762/bjoc.21.199

• product. They resolved racemic intermediate 27 by derivatization with (S)-1-(1-naphthyl)ethyl isocyanate, followed by separation of the resulting diastereomers via silica gel chromatography (Scheme 3). By converting diastereomer 32 to (−)-illisimonin A, the absolute configuration of the natural product

Rapid access to the core of malayamycin A by intramolecular dipolar cycloaddition

• Yilin Liu,
• Yuchen Yang,
• Chen Yang,
• Sha-Hua Huang,
• Jian Jin and
• Ran Hong

Beilstein J. Org. Chem. 2025, 21, 2542–2547, doi:10.3762/bjoc.21.196

• is secured from the commercial source. Results and Discussion Based on the known protocol [33], diacetone-ᴅ-allofuranose 8 was first introduced with a propargyl group (Scheme 2A). Upon treatment of AcOH to afford diol 9, oxidative cleavage with Shing’s protocol (NaIO4 on silica gel) [34] proceeded

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

• % (irradiated). Moreover, gel-phase DPPC bilayers also exhibited an increase in release from 7% to 14%. On the contrary, highly fluid pure EYPC bilayers showed high baseline release upon rotaxane incorporation (64%), with photoswitching producing only a slight increase (70%), as most dye was released within the

• permeabilization was assessed by monitoring the release of encapsulated sulforhodamine B dye, serving as a reporter for membrane perturbation. Specifically, we examined LUVs in the liquid-disordered (Ld), liquid-ordered (Lo), and gel (Lβ) phases. As control molecules, we also investigated the membrane perturbation

• formation of liquid-ordered (Lo) domains [16]. To further assess the effect of membrane rigidity on rotaxane behavior, we also studied LUVs composed solely of DPPC lipids, which form a highly ordered gel phase (Lβ) at room temperature due to their saturated acyl chains [17]. Rotaxane 1 was incorporated into

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

• mixture was filtered through a Celite pad, and the filtrate was concentrated using a rotary evaporator. The crude residue was purified through silica gel column chromatography using n-hexane/EtOAc 99:1 as eluent to give the pure C1-nitrated carbazole 2. ORTEP diagram of compound 2a (CCDC 2478298

Ex-situ generation of gaseous nitriles in two-chamber glassware for facile haloacetimidate synthesis

• Nikolai B. Akselvoll,
• Jonas T. Larsen and
• Christian M. Pedersen

Beilstein J. Org. Chem. 2025, 21, 2465–2469, doi:10.3762/bjoc.21.188

• of difluoroacetimidates was therefore attempted, but in our hands, these proved even more unstable than the trifluoroacetimidates and were not possible to isolate by chromatography due to decomposition. However, the purity of these compounds, after filtration through a block of silica gel, was

• was the p-methoxy derivative 11 which, as expected, was more reactive and hence more difficult to purify due to decomposition on silica gel. The p-methoxybenzyl trifluoroacetimidate (9) has been shown to be an effective regent for the acid-catalyzed benzylation of alcohols [12][30]. Conclusion In

Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds

• Natalya Akhmetdinova,
• Ilgiz Biktagirov and
• Liliya Kh. Faizullina

Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185

• 90% yield to (+)-stephadiamine (71). The authors noted that the identification of the structure of (+)-stephadiamine (71) was carried out without purification of the reaction mixture due to its instability on a silica gel column under acidic or basic conditions. Zhang et al. [47] proposed an

The high potential of methyl laurate as a recyclable competitor to conventional toxic solvents in [3 + 2] cycloaddition reactions

• Ayhan Yıldırım and
• Mustafa Göker

Beilstein J. Org. Chem. 2025, 21, 2389–2415, doi:10.3762/bjoc.21.184

• performed using silica gel (60 F254, Merck, Darmstadt, Germany) plates. Melting points were recorded using a Büchi melting point B-540 apparatus (Büchi Labortechnik AG in Flawil, Switzerland). The IR spectra were measured by Spectrum Two FT-IR spectrometer (PerkinElmer, Massachusetts, USA). The NMR spectra

Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications

• Jullyane Emi Matsushima,
• Khushbu,
• Zuliah Abdulsalam,
• Udyogi Navodya Kulathilaka Conthagamage and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179

• photoisomerization of the stilbenes caused the cyclodextrin to displace along the axle, resulting in rapid and significant contraction or expansion of the gels. Moreover, stilbene photoisomerization was used to perform bending motions and lift a weight 15 times heavier than the dry gel. Contrary to stilbenes, stiff

Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis

• Peng-Xi Luo,
• Jin-Xuan Yang,
• Shao-Min Fu and
• Bo Liu

Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177

• southern furan moiety of 69. Finally, hydrolysis of the carbonate followed by oxidation of the resulting diol completed the Norrish–Yang cyclization precursor gracilisoid A (49). Irradiation of 49 under anaerobic conditions with a CFL, followed by treatment with silica gel, successfully generated a pair of

• separable regioisomers: gracilisoid F (54) in 42% yield and gracilisoid H (56) in 40% yield, respectively (Scheme 8). Here, light triggered a regiodivergent Norrish–Yang cyclization, while the acidic nature of silica gel sufficiently promoted an α-hydroxy ketone rearrangement. This type of rearrangement was

Pathway economy in cyclization of 1,n-enynes

• Hezhen Han,
• Wenjie Mao,
• Bin Lin,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173

• activated ynamide. This sequence resulted in the formation of spiroindoleninium intermediate 130 (Scheme 27, path a). Subsequent intramolecular Mannich cyclization proceeded, yielding the 1H-pyrrolo[2,3-d]carbazole derivatives 131. When silica gel was utilized as the catalytic medium, the same Michael

• addition happened to generate the spiroindoleninium intermediate. This transient species was subsequently trapped by water physisorbed in the silica gel, forming hemiaminal adduct 132. A 1,5-hydride shift was then mediated by Al2O3, ultimately affording the spiro[indoline-3,3'-pyrrolidin]-2-one derivatives

Thiadiazino-indole, thiadiazino-carbazole and benzothiadiazino-carbazole dioxides: synthesis, physicochemical and early ADME characterization of representatives of new tri-, tetra- and pentacyclic ring systems and their intermediates

• Gyöngyvér Pusztai,
• László Poszávácz,
• Anna Vincze,
• András Marton,
• Ahmed Qasim Abdulhussein,
• Judit Halász,
• András Dancsó,
• Gyula Simig,
• György Tibor Balogh and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169

• spectrometer equipped with a Direct Insertion Probe (EI+ ionization) or on a Bruker Q-TOF Maxis Impact mass spectrometer (ESI+ ionization) coupled with a Waters Acquity I-Class UPLC system equipped with a diode array detector. The reactions were followed by analytical thin-layer chromatography on silica gel 60

A m-quaterphenyl probe for absolute configurational assignments of primary and secondary amines

• Yuka Takeuchi,
• Mutsumi Kobayashi,
• Yuuka Gotoh,
• Mari Ikeda,
• Yoichi Habata,
• Tomohiko Shirai and
• Shunsuke Kuwahara

Beilstein J. Org. Chem. 2025, 21, 2211–2219, doi:10.3762/bjoc.21.168

• structure analysis was performed on a Bruker SMART diffractometer equipped with a CCD area detector at 120 K. Silica gel 60 F254 precoated plates on glass from Merck Ltd. were used for thin-layer chromatography (TLC). General procedure for the synthesis of conjugates 2a–h (S)-2-[2,10-Bis(4-methoxyphenyl

• of Celite, and then evaporated to dryness. The crude product was purified by column chromatography on silica gel (EtOAc) to yield amine (S)-2a (203 mg, 83% yield) as colorless solid: mp 164.2–165.5 °C; 1H NMR (400 MHz, CDCl3) δ 7.73 (d, J = 1.8 Hz, 2H), 7.62–7.56 (m, 6H), 7.44 (d, J = 7.8 Hz, 2H