Synthesis and characterization of a isothiouronium-calix[4]arene derivative: self-assembly and anticancer activity

• Giuseppe Granata,
• Loredana Ferreri,
• Claudia Giovanna Leotta,
• Giovanni Mario Pitari and
• Grazia Maria Letizia Consoli

Beilstein J. Org. Chem. 2025, 21, 2535–2541, doi:10.3762/bjoc.21.195

• Instrument, Malvern, UK) equipped with a 633 nm laser, at a scattering angle of 90° and 25 °C temperature. The size of the particles was calculated from the diffusion coefficient using the Stokes–Einstein equation: where D is the diffusion coefficient, k is the Boltzmann constant, T is the absolute

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

• /Chol 6:4 bilayers, the macrocycle may be unable to reach the lipid–water interface or reposition effectively within this more viscous bilayer. This could be due to limited diffusion within the tightly packed lipids and/or the increased bilayer thickness, which likely hinders the structural

Research progress on calixarene/pillararene-based controlled drug release systems

• Liu-Huan Yi,
• Jian Qin,
• Si-Ran Lu,
• Liu-Pan Yang,
• Li-Li Wang and
• Huan Yao

Beilstein J. Org. Chem. 2025, 21, 1757–1785, doi:10.3762/bjoc.21.139

• -controlled, diffusion-controlled, osmotic-controlled (which encompasses osmotic pressure and swelling control), chemically controlled, nanoparticle systems, and supramolecular controlled-release systems. Among these, supramolecular controlled-release systems have advantages such as dynamic adjustability

Unique halogen–π association detected in single crystals of C–N atropisomeric N-(2-halophenyl)quinolin-2-one derivatives and the thione analogue

• Mai Uchibori,
• Nanami Murate,
• Kanako Shima,
• Tatsunori Sakagami,
• Ko Kanehisa,
• Gary James Richards,
• Akiko Hori and
• Osamu Kitagawa

Beilstein J. Org. Chem. 2025, 21, 1748–1756, doi:10.3762/bjoc.21.138

• vapour diffusion of hexane into a methanol solution of the compound at room temperature) and their X-ray crystal structural analyses were performed (Figure 2) [33]. In the crystals of rac-1a, a π-type intermolecular interaction between the bromine atom and the benzene ring of the quinolinone was found

• observed in the crystals of optically pure forms (P)-1a,b (Figure 3, single crystals of (P)-1a,b were obtained by vapour diffusion of hexane into a methanol solution of the compound at room temperature) [34]. Meanwhile, the halogen atoms in (P)-1a,b were found to interact with the C4 atom on the lactam

Facile synthesis of hydantoin/1,2,4-oxadiazoline spiro-compounds via 1,3-dipolar cycloaddition of nitrile oxides to 5-iminohydantoins

• Juliana V. Petrova,
• Varvara T. Tkachenko,
• Victor A. Tafeenko,
• Anna S. Pestretsova,
• Vadim S. Pokrovsky,
• Maxim E. Kukushkin and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 1552–1560, doi:10.3762/bjoc.21.118

• -dipoles. These techniques differed in the method of introducing the base necessary for generating the 1,3-dipole into the reaction medium, and included the base addition “drop by drop” or using a diffusion mixing procedure [21]. We found that the formation of spiro-compounds occurs chemo- and

• triethylamine solution was slowly added dropwise to the reaction mixture at 0 °C under an inert gas atmosphere to avoid moisture from the air (“classical” method). In another method, the base was inserted via diffusion of NEt3 into a solution containing the dipolarophile and dipole precursor (see Figure S1 in

• near or superior to those obtained by diffusion mixing. However, there were three exceptions (5d, 5g and 5h) where we observed a significant difference in the results. The most striking example was compound 5h, which exhibited a yield decrease of more than a third when the diffusion mixing technique

Gold extraction at the molecular level using α- and β-cyclodextrins

• Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

• added to reach a final concentration of 0.25% (v/v). To better understand the role of DBC, crystals of the ternary complex β-CD·KAuBr4·DBC were obtained by slow vapor diffusion of DBC into an aqueous solution of KAuBr4 and β-CD over three days. Single-crystal diffraction showed the [AuBr4]− anion

Supramolecular assembly of hypervalent iodine macrocycles and alkali metals

• Krishna Pandey,
• Lucas X. Orton,
• Grayson Venus,
• Waseem A. Hussain,
• Toby Woods,
• Lichang Wang and
• Kyle N. Plunkett

Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87

• further understand the complexation with metal cations, separate co-crystals of HIM 1 with LiBArF20 and NaBArF24 were obtained by vapor diffusion of diethyl ether into acetone. The details of the co-crystallization experiment are provided in the crystallographic information section of Supporting

Dicarboxylate recognition based on ultracycle hosts through cooperative hydrogen bonding and anion–π interactions

• Wen-Hui Mi,
• Teng-Yu Huang,
• Xu-Dong Wang,
• Yu-Fei Ao,
• Qi-Qiang Wang and
• De-Xian Wang

Beilstein J. Org. Chem. 2025, 21, 884–889, doi:10.3762/bjoc.21.72

• target ultracyclic hosts. The synthesized ultracycles were fully characterized by spectrometric and elemental analysis (Scheme 1 and Schemes S1‒S3 in Supporting Information File 1). Single crystals of B4aH were obtained by slow vapor diffusion of ethyl ether into an acetonitrile/chloroform 1:1 (v/v

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

• understand cooperative interactions between complexed ions, we tried to grow the crystal structure of studied salts. Fortunately, single crystals of Cs2CO3 and Cs3PO4 complexes were obtained by slow vapor diffusion from acetonitrile and diethyl ether. Notably, clearly stronger ion-dipole interactions of

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

• are non-covalently bound to their fluorophore and despite high (usually nanomolar) binding affinities this can pose problems for RNA live-cell imaging. For instance, diffusion of the ligand and non-specific binding lead to unfavorable background and/or signal loss [10]. To address these problems, our

Photocatalyzed elaboration of antibody-based bioconjugates

• Marine Le Stum,
• Eugénie Romero and
• Gary A. Molander

Beilstein J. Org. Chem. 2025, 21, 616–629, doi:10.3762/bjoc.21.49

• functionalized ruthenium complex and a fragment crystallizable (Fc) ligand anchored to a magnetic bead, enabling the localized generation of singlet oxygen near antibodies (Figure 4B). The short lifetime and limited diffusion of singlet oxygen ensure exclusive reactions with proximal histidine residues. This

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

• oxidation) and 6b (one-electron oxidation) into the respective bromine(III) species (Scheme 3C) [17] demonstrated a more similar behaviour to 6b suggesting that revealed oxidation is a single-electron-transfer process. It is important to note that this comparison assumes that the diffusion coefficients of

• hypobromite D. The latter decomposes into bromide and hexafluoroacetone, with the latter observed by 19F NMR [25]. Assuming that intermediate B is sufficiently stable to leave the diffusion layer and undergoes disproportionation to the species C in the bulk electrolyte provides a reasonable explanation for

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

• length (including 6 for n = 5), the decontamination process is slow and the costs are high. Additionally, it could not remove the trace amount of the residual impurity, potentially due to inefficient diffusion of the substrate into the resin at low concentrations. We next sought to use soluble amines to

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

• Dmitry E. Shybanov Maxim E. Kukushkin Eugene V. Babaev Nikolai V. Zyk Elena K. Beloglazkina Department of Chemistry, M. V. Lomonosov Moscow State University, 119991 Moscow, Russian Federation 10.3762/bjoc.21.18 Abstract A diffusion mixing technique with a volatile reagent was successfully used to

• main reaction products. Keywords: aldol condensation; [4 + 2]-cycloaddition; diffusion mixing; formaldehyde; Knoevenagel condensation; three-component reactions; Introduction Formaldehyde is a reactive electrophilic reagent widely used as a C1 building block in multicomponent reactions [1][2][3]. Its

• reactions that proceed through the formation of formaldehyde condensation products (Scheme 1). Previously, we have proposed a convenient diffusion mixing technique for multicomponent reactions based on the absorption of volatile reagent vapors by a mixture containing the remaining reaction components. This

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• –π interactions with the potential to form nanoscale pure and mixed domains in the bulk heterojunction on the length scale of the exciton diffusion length (5–15 nm), leading to an efficient exciton dissociation and charge generation [12]. Figure 3 gives an insight into the spatial distribution and

Anion-dependent ion-pairing assemblies of triazatriangulenium cation that interferes with stacking structures

• Yohei Haketa,
• Takuma Matsuda and
• Hiromitsu Maeda

Beilstein J. Org. Chem. 2024, 20, 2567–2576, doi:10.3762/bjoc.20.215

• orthogonal arrangement in comparison with the phenyl moieties in 1b+. Solid-state ion-pairing assemblies of the ion pairs 2+-X− (X− = Cl−, BF4−, PF6−, B(C6F5)4−, and PCCp−) were investigated by X-ray analysis of the orange rod-shaped single crystals, which were obtained by vapour diffusion using CHCl3/n

• characterized by single-crystal X-ray diffraction analysis. Method for single-crystal X-ray analysis Crystallographic data are summarized in Table 1. A single crystal of 2+-Cl− was obtained by vapor diffusion of n-heptane into a CHCl3 solution. The data crystal was a red prism of approximate dimensions 0.20 mm

• × 0.02 mm × 0.01 mm. A single crystal of 2+-BF4− was obtained by vapor diffusion of n-heptane into a CHCl3 solution. The data crystal was a red prism of approximate dimensions 0.30 mm × 0.10 mm × 0.05 mm. A single crystal of 2+-PF6− was obtained by vapor diffusion of n-hexane into a CH2Cl2 with small

Cell-free protein synthesis with technical additives – expanding the parameter space of in vitro gene expression

• Tabea Bartsch,
• Stephan Lütz and
• Katrin Rosenthal

Beilstein J. Org. Chem. 2024, 20, 2242–2253, doi:10.3762/bjoc.20.192

• cell are much more complex than what can be mimicked by the sole addition of a polymer. The diffusion of macromolecules depends on the perceived viscosity in the cell, which is inhomogeneous and depends on the location in the cell and its growth phase [50][51]. Comparing the salt concentrations, the

Factors influencing the performance of organocatalysts immobilised on solid supports: A review

• Zsuzsanna Fehér,
• Dóra Richter,
• Gyula Dargó and
• József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

• immobilization strategies, including covalent bonding and encapsulation, cater to different polymer types. Soluble polymers enhance diffusion, while insoluble ones ensure stability and high loading capacities [42]. Silica is also widely applied due to its ease of functionalisation and thermal stability [43]. The

• catalyst closer to the support, impacting electronic properties and ligand conformation. With large catalyst molecules, the pores of an ordered mesoporous material being similar in size to the catalyst can create significant diffusion barriers as the catalyst attempts to enter the pores. As a result, the

• dimensions of the support, but can also be influenced by several other factors. In a homogeneous system, rapid diffusion, and creation of catalyst–reactant interactions are possible because the organocatalyst is dissolved in the reaction mixture. However, in a solid-supported organocatalyst, the reactants

Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies

• Beatrice E. Jones,
• Camille Blayo,
• Jake L. Greenfield,
• Matthew J. Fuchter,
• Nathan Cowieson and
• Rachel C. Evans

Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176

• . It should be noted that a lag between the time taken to reach the PSS and the time for the new micelle morphology to form is expected. This is due to the additional time that is required for diffusion and reassembly of the AzoTAB in the Z conformation into the new equilibrium structure [22]. The

• viscosity, from 0.89 in H2O to 1.10 mPa⋅s in D2O [42], which is attributed to slow diffusion of micelles within the medium. Furthermore, the rate of H+/D+ exchange between the solvent and the photoswitch will decrease due to the heavier deuterium atoms in D2O, resulting in an effective weakening of the

• decreased rate of diffusion in the more viscous D2O could lead to slower rearrangement after reverse isomerisation into the E isomer morphology. This demonstrates that the solvent plays a crucial role in X-ray-induced reverse isomerisation in these systems, not only due to catalysis from the radiolysis

2-Heteroarylethylamines in medicinal chemistry: a review of 2-phenethylamine satellite chemical space

• Carlos Nieto,
• Alejandro Manchado,
• Ángel García-González,
• David Díez and
• Narciso M. Garrido

Beilstein J. Org. Chem. 2024, 20, 1880–1893, doi:10.3762/bjoc.20.163

• diffusion features related to these changes. The amino acid ʟ-histidine has attracted the attention of the medicinal chemistry community due to its properties not only in the aforementioned histaminergic system, but also as metal-ion chelator, proton buffering modulator, and antioxidant. Considering the

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

• Yong-Chang Zhai,
• Shimon Oiwa,
• Shinobu Aoyagi,
• Shohei Ohno,
• Tsubasa Mikie,
• Jun-Zhuo Wang,
• Hirofumi Amada,
• Koki Yamanaka,
• Kazuhira Miwa,
• Naoyuki Imai,
• Takeshi Igarashi,
• Itaru Osaka and
• Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

• time. A single crystal of t-Bu-FIDS was grown by liquid–liquid diffusion method (CS2/EtOH). The crystal structure was successfully analyzed using synchrotron radiation at SPring-8. The crystal exhibited the orthorhombic space group (No. 61) with the D2h point group, and the structure confirmed the 1,2

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• cage escape quantum yields [67][68]. Aza-H exhibits a relatively long singlet lifetime of 9.6 ns (see Figure 4E), which is sufficient for diffusion-controlled energy or electron transfer at moderate substrate concentrations. Transient absorption (TA) spectra of an Ar-saturated Aza-H solution were

• of magnitude slower than the diffusion limit in MeCN, the long triplet lifetime ensures a quenching efficiency of 85% when a concentration of 200 mM cinnamyl chloride is used. Exposed to 427 nm irradiation with 1 mol % Aza-H 41% of the chlorocyclopropane and 50% of the branched allylic chloride was

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• were obtained using the liquid–liquid bilayer diffusion method with solutions of 3 in CS2 using hexane as a poor solvent at 0 °C. Single-crystal X-ray diffraction data of 3 were collected on a Rigaku Oxford Diffraction XtaLAB Synergy R DW system with a HyPix detector equipped with a nitrogen-gas flow

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• was an important issue, resulting in a limitation of reagents’ diffusion. The addition of a small amount of CH2Cl2 was thus considered (Table 1, entries 5 and 6) and resulted in a substantial selectivity improvement. The achievement of a better homogeneity, let it possible to further reduce the

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• hydrochlorination is operating within the rate of diffusion control (Figure 4). They also noted that the reaction was significantly slower at room temperature when compared to reactions carried out at 0 °C. However, reaction rates were exclusively reported at 0 and −45 °C, indicating an inverse temperature