Light-enabled intramolecular [2 + 2] cycloaddition via photoactivation of simple alkenylboronic esters

• Lewis McGhie,
• Hannah M. Kortman,
• Jenna Rumpf,
• Peter H. Seeberger and
• John J. Molloy

Beilstein J. Org. Chem. 2025, 21, 854–863, doi:10.3762/bjoc.21.69

• detrimental to reactivity leading to substrate degradation. Given the ease of access and enhanced stability of pinacol esters to column chromatography, this motif was advanced for further reaction design. Cyclic voltammetry analysis of 1a indicates that single-electron-transfer processes with the excited

Unraveling cooperative interactions between complexed ions in dual-host strategy for cesium salt separation

• Zhihua Liu,
• Ya-Zhi Chen,
• Ji Wang,
• Qingling Nie,
• Wei Zhao and
• Biao Wu

Beilstein J. Org. Chem. 2025, 21, 845–853, doi:10.3762/bjoc.21.68

• determined extraction efficiency (extracted Cs+ versus the initial amount; concentrations were recorded by ion chromatography) of CsCl, CsNO3, Cs2CO3, Cs2SO4 and Cs3PO4 were 82%, 36%, 61%, 41%, and 100%, respectively. In contrast, by using an individual 18-crown-6 or hexaurea receptor, a clear enhancement of

Substituent effects in N-acetylated phenylazopyrazole photoswitches

• Radek Tovtik,
• Dennis Marzin,
• Pia Weigel,
• Stefano Crespi and
• Nadja A. Simeth

Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66

• hydrazine or methylhydrazine to yield NH-PAPs or NMe-PAPs, respectively, in high to quantitative yields. The NAc-PAPs were synthesized via an acetylation reaction of NH-PAPs with acyl chloride, forming the novel NAc-PAPs. While the molecules could be extracted and purified by column chromatography without

4-(1-Methylamino)ethylidene-1,5-disubstituted pyrrolidine-2,3-diones: synthesis, anti-inflammatory effect and in silico approaches

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Luc Van Meervelt,
• Do Thi Thao and
• Nguyen Minh Thong

Beilstein J. Org. Chem. 2025, 21, 817–829, doi:10.3762/bjoc.21.65

• further purification. For column chromatography, 70–230 mesh silica 60 (E. M. Merck) was used as the stationary phase. Electrospray ionization–high-resolution mass spectra (ESI–HRMS) were acquired on a SCIEX X500 QTOF instrument in the positive ion mode. A Büchi melting point B-545 apparatus was used to

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• was proposed by conducting the reaction in the presence of TEMPO (Scheme 7). The electron-deficient and sterically encumbered diaminophosphine oxide could also produce the corresponding products in this method. Gas chromatography analysis confirmed that molecular hydrogen was the only byproduct of

Orthogonal photoswitching of heterobivalent azobenzene glycoclusters: the effect of glycoligand orientation in bacterial adhesion

• Leon M. Friedrich and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2025, 21, 736–748, doi:10.3762/bjoc.21.57

• pure 6βGlc 3 in 77% yield after reversed-phase chromatography (Scheme 2A). To furnish the glycoazobenzene antenna 4, complementary to 3, the azobenzene thiomannopyranoside 10 (cf. Scheme 1), representing the mannose analog of 15, was used and cross-coupled with 14 to give the acetylated glycoazobenzene

Synthesis of HBC fluorophores with an electrophilic handle for covalent attachment to Pepper RNA

• Raphael Bereiter and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 727–735, doi:10.3762/bjoc.21.56

• . Chemical reagents and solvents were purchased in the highest available quality from commercial suppliers (Merck/Sigma-Aldrich, ABCR) and used without further purification. Analytical thin-layer chromatography (TLC) was performed on Macherey-Nagel Polygram® SIL G/UV254 plates. 0.2 mm silica gel 60 for

• column chromatography was purchased from Macherey-Nagel. 1H and 13C NMR spectra were recorded on a Bruker UltrashieldTM 400 MHz Plus or a 700 MHz Avance Neo spectrometer. Chemical shifts (δ) are reported relative to tetramethylsilane (TMS), referenced to the residual solvent signal (DMSO-d6: 2.50 ppm for

• Na2SO4 and concentrated to dryness. Finally, the crude compound was purified via silica gel chromatography using 50–70% ethyl acetate in cyclohexane as gradient. General procedure B. The product obtained in general procedure A was dissolved in ethanol mixed with 4-cyanophenylacetonitrile and 8 drops of

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

• Maurizio Iannuzzi,
• Thomas Hohmann,
• Michael Dyrks,
• Kilian Haoues,
• Katarzyna Salamon-Krokosz and
• Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

• alkylation yield of 68%. Since two desired diastereomers are formed in this case, they had to be subsequently separated from one another. This was accomplished using flash column chromatography. The respective Ni(II) complexes of TfLeu (11a, 11b) could be isolated with excellent diastereomeric purities of 95

• (HREIMS) were measured on a MAT 711 (Varian MAT, Bremen, Germany). Electron energy for EI was set to 70 eV. Infrared spectra (IR) were measured on an ALPHA II (Bruker, Billerica, USA) spectrometer. Characteristic absorption bands are given in wave numbers (cm−1). Qualitative thin-layer chromatography (TLC

• ) was carried out on aluminum plates coated with silica gel 60 F254 (Merck, Darmstadt, Germany). The TLC plates were analyzed using UV light at 254 nm. Flash chromatography was performed on silica gel 60 M from Macherey-Nagel (grain size of 40−63 μm). The conditions are given in the form “(A/B = a:b

Entry to 2-aminoprolines via electrochemical decarboxylative amidation of N‑acetylamino malonic acid monoesters

• Olesja Koleda,
• Janis Sadauskis,
• Darja Antonenko,
• Edvards Janis Treijs,
• Raivis Davis Steberis and
• Edgars Suna

Beilstein J. Org. Chem. 2025, 21, 630–638, doi:10.3762/bjoc.21.50

• column chromatography. Cyclic voltammetry studies CV experiments were carried out in an SVC-2 (ALS, Japan) three-electrode cell using a PalmSens4 (PalmSens). A glassy carbon disk (diameter: 1.6 mm) served as the working electrode and a platinum wire as the counter electrode. The glassy carbon disk was

Sequential two-step, one-pot microwave-assisted Urech synthesis of 5-monosubstituted hydantoins from L-amino acids in water

• Wei-Jin Chang,
• Sook Yee Liew,
• Thomas Kurz and
• Siow-Ping Tan

Beilstein J. Org. Chem. 2025, 21, 596–600, doi:10.3762/bjoc.21.46

• this study, we present an innovative, sustainable approach to synthesizing hydantoins (H2a–j) directly from amino acids. This method employs a column chromatography-free, two-step, one-pot microwave-assisted synthesis that delivers hydantoins in yields ranging from 34% to 89%. The protocol demonstrates

• of this process is promising, driven by its simplicity, moderate to high yields, and the use of environmentally friendly reagents. Notably, microwave-assisted one-pot reactions eliminate the need for column chromatography, a common step in traditional purification methods but limits scalability

• further demonstrate its potential for large-scale, environmentally responsible production. Conclusion In conclusion, we report a facile, environmentally friendly, chromatography-free hydantoin synthesis method using a sequential two-step, one-pot microwave-assisted method. This strategy utilizes amino

Vinylogous functionalization of 4-alkylidene-5-aminopyrazoles with methyl trifluoropyruvates

• Judit Hostalet-Romero,
• Laura Carceller-Ferrer,
• Gonzalo Blay,
• Amparo Sanz-Marco,
• José R. Pedro and
• Carlos Vila

Beilstein J. Org. Chem. 2025, 21, 533–540, doi:10.3762/bjoc.21.41

• chromatography. Diastereoisomeric ratio (dr) determined by 1H NMR of the crude reaction mixture. Plausible mechanism and X-ray structure of compound 5aca. Optimization of the reaction conditions.a Supporting Information Supporting Information File 14: Detailed experimental procedures, characterization data, and

Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• chlorine gas, with the reaction conducted by stirring the pyrazolinone with TCICA in DCM for 18 hours. Bimanes can be purified easily using column chromatography with silica gel as the stationary phase, with the compounds Cl2B, Me2B, and Me4B only requiring neat DCM as the eluent. After chromatographic

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

• novel 2,6-diamino preQ1 analog 2 (DPQ1) by hydrogenation of 8 (DPQ0 [32]) (Scheme 2). In this case, however, a final purification step (by reversed-phase chromatography) was required. Notably, using the hydrogenation conditions described here, we were also able to streamline our previously reported 7

• mild reduction with methanolic sodium borohydride. Upon purification by reversed-phase chromatography using aqueous hydrobromic acid as eluent (0.5% in H2O), a considerable fraction of the alcohols was already converted to the desired bromides 4c,d. Only in the case of 4b, no deoxygenative bromination

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

• chromatography [1]. Sometime later, kinetic resolution (KR) emerged. This method is based on the different reaction rates of each enantiomer in a racemic mixture when they are reacted with a reagent, a chiral catalyst, or an enzyme. This process results in obtaining the less reactive enantioenriched enantiomer

• ] using 20 mol % of catalyst A and 20 mol % of p-nitrobenzoic acid (PNBA) as co-catalyst in different solvents at room temperature. The results obtained are summarized in Scheme 3 and Table 1. The progress of the reaction was monitored using thin-layer chromatography (TLC) and 1H NMR analysis of the

• a one dm path length, and concentration was given in grams per 100 mL. TLC analysis was performed on glass-backed plates coated with silica gel 60 and an F254 indicator and visualized by either UV irradiation or staining with phosphomolybdic acid solution. Flash chromatography uses silica gel (230

Electrochemical synthesis of cyclic biaryl λ³-bromanes from 2,2’-dibromobiphenyls

• Andrejs Savkins and
• Igors Sokolovs

Beilstein J. Org. Chem. 2025, 21, 451–457, doi:10.3762/bjoc.21.32

• extractive workup followed by reversed-phase chromatography and its structure was unambiguously confirmed by X-ray crystallography (Table 1, graphic). Gratifyingly, a two-fold increase in the yield was achieved by a slight reduction of the current density to j = 8 mA·cm−2 (entry 2 vs entry 1 in Table 1). A

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• able to adapt this chemistry to work in situ, allowing soluble metastable imine frameworks to be trapped as amides [38]. The adapted cages were soluble, and were now stable enough to be purified by gel-permeation (size-exclusion) chromatography (useful when precipitation is not possible), which is

Identification and removal of a cryptic impurity in pomalidomide-PEG based PROTAC

• Bingnan Wang,
• Yong Lu and
• Chuo Chen

Beilstein J. Org. Chem. 2025, 21, 407–411, doi:10.3762/bjoc.21.28

• to generate an inseparable byproduct. By contrast, the byproduct derived from Boc-protected amines has a significantly different retention time on HPLC and could be removed by regular silica gel chromatography. Because the formation of 5‒7 posts a significant purification challenge, we sought to

• silica gel column chromatography. The LUMO and electrostatic charges of thalidomide and its derivatives by DFT calculation at the ωB97X-D/6-311+G** level. The synthetic route for iVeliparib-AP6. The conversion of byproduct 6 to 10 to facilitate its removal. Effects of the length and functionalization of

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• temperature (23 °C). Chromatography was carried out on columns filled with Al2O3 of II–III degree of activity according to Brockmann. Melting points were determined on a Fisher-Johns melting point apparatus. 1,1,2-Trimethyl-1H-benzo[e]indolenine (2a, 98%, Alfa Aesar), 2,3,3-trimethyl-3H-benzo[g]indolenine (2b

Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates

• Kirill A. Gomonov,
• Vasilii V. Pelipko,
• Igor A. Litvinov,
• Ilya A. Pilipenko,
• Anna M. Stepanova,
• Nikolai A. Lapatin,
• Ruslan I. Baichurin and
• Sergei V. Makarenko

Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24

• -dihydronaphtho[1,2-b]furan-3-carboxylate 4a,b with a total yield of up to 73% (ratio 3a/4a = 2:1; 3b/4b = 2:1, according to 1H NMR spectroscopy) (Scheme 4). Using preparative chromatography, the mixture was separated into individual substances. In turn, alkyl 7,7-dimethyl-4,9-dioxo-6,7,8,9-tetrahydro-4H-furo[3,2

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

• (15 g) was analyzed by LC–MS. Thereafter, it was fractionated by vacuum liquid chromatography (VLC) using silica gel as a stationary phase. The elution procedure was performed using a chromatographic scheme of two different gradients as follows: 1) n-heptane/EtOAc (1:0, 7:3, 3:7, 0:1) followed by

Three-component reactions of conjugated dienes, CH acids and formaldehyde under diffusion mixing conditions

• Dmitry E. Shybanov,
• Maxim E. Kukushkin,
• Eugene V. Babaev,
• Nikolai V. Zyk and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 262–269, doi:10.3762/bjoc.21.18

• days (TLC or NMR control). After completion of the reaction, the solvent was removed under reduced pressure, and the residue was purified by column chromatography on silica gel using chloroform as eluent. ((1S,4S)-Bicyclo[2.2.1]hept-5-ene-2,2-diyl)bis(phenylmethanone) (8) and phenyl((4aR,7aS)-2-phenyl

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

• solution, extracted with ether, washed with brine, dried over MgSO4, filtered, and concentrated in vacuo. The crude product was purified by column chromatography on silica gel using n-hexane and ethyl acetate 95:5 to give 1.4 g of I2(a) in 50% yield. 1H NMR (300 MHz, CDCl3, TMS) δ = 2.55 (d, JHF = 3.2 Hz

• brine, dried over MgSO4, filtered, and concentrated in vacuo. The crude product was purified by column chromatography on silica gel using n-hexane to give 2.8 g of I4(a) in 56% yield. 1H NMR (300 MHz, CDCl3, TMS) δ = 2.42 (s, 3H, CH3), 7.29–7.34 (m, 1H, aromatic H), 7.40–7.46 (m, 1H, aromatic H), 7.49

• reaction mixture was neutralized by HCl aqueous solution, extracted with ether, washed with brine, dried over MgSO4, filtered, and concentrated in vacuo. The crude product was purified by column chromatography on silica gel using n-hexane and ethyl acetate 8:2 and recycling HPLC using chloroform as the

Heteroannulations of cyanoacetamide-based MCR scaffolds utilizing formamide

• Marios Zingiridis,
• Danae Papachristodoulou,
• Despoina Menegaki,
• Konstantinos G. Froudas and
• Constantinos G. Neochoritis

Beilstein J. Org. Chem. 2025, 21, 217–225, doi:10.3762/bjoc.21.13

• specific MCR-based scaffolds as precursors and employing the abundant and inexpensive formamide as a C1 feedstock under neat conditions, we were able to efficiently access substituted thieno-, quinolino- and indolopyrimidones without the need of column chromatography. Further, a single-crystal X-ray

• obtained 15 diversely substituted heteroannulated pyrimidones, employing privileged thiophene, quinoline and indole scaffolds in a rapid fashion, without the need of column chromatography, in a parallel setup. Heteroannulated pyrimidones in drug discovery: blockbuster drugs that are based on the privileged

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

• JMS-T100GCV or a JEOL JMS-T200GC spectrometer. All the reactions were conducted under argon or nitrogen. Materials: Column chromatography was conducted on silica gel (Silica Gel 60 N, Kanto Chemical Co., Inc.). Toluene and N,N-dimethylformamide (DMF) were purified by a solvent-purification system

• . After removal of the solvent under reduced pressure, the residue was purified by silica gel column chromatography (hexane/EtOAc = 10:1) to give 3bb (76 mg, 98%) as a white solid. 1H NMR (500 MHz, CDCl3) δ 8.15 (d, J = 8.2 Hz, 1H), 7.93 (d, J = 8.2 Hz, 1H), 7.75–7.67 (m, 4H), 7.58 (ddd, J = 8.2, 6.9, 1.2

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