Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

• Lucía Campos-Prieto,
• Aitor García-Rey,
• Eddy Sotelo and
• Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

• biomolecules like DNA and lipids. Lipid peroxidation and membrane disruption can cause random cross-linking, resulting in cell death and the fragmentation of proteins and enzymes. Elevated concentrations of reactive oxygen species (ROS) from various molecular processes contribute to the oxidation of proteins

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• cross-linking of the hydroxy groups on CDs could extend the molecular/material design. As the di-isocyanate macromonomer was used for long axle components, the coverage ratio of CDs in this system was 3–5%, which was significantly lower than those of other systems in 2020. The mechanical properties of

Photoluminescence color-tuning with polymer-dispersed fluorescent films containing two fluorinated diphenylacetylene-type fluorophores

• Kazuki Kobayashi,
• Shigeyuki Yamada,
• Motohiro Yasui and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2682–2690, doi:10.3762/bjoc.20.225

• as electron-donating groups was shown to promote intramolecular charge transfer (ICT) and shifted the PL wavelength to longer wavelengths, resulting in yellow or orange fluorescence in the solid state [21][22]. In addition, cross-linking between the amino group and attached benzene ring effectively

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

• -FF fibres (Figure 3). However, Fourier-transform infrared spectroscopy indicated that the Fmoc-S assembled on the surface of the Fmoc-FF fibres. The addition of carboxylate ions at the fibre surface allows cross-linking to occur, altering the bulk physical properties of the gel [20]. While the

• the two fibril cross-sections increasing the interactions with the electron. The uniform contrast was instead indicative of the branching as a result of valine facial collapse of β-hairpin, giving rise to multifunctional branches which allow cross-linking. The capabilities of imaging in elucidating

• resulting from these defects could be gauged by SEM since the braid crossings are topologically fixed and act as permanent junctions [44]. Cross-linking caused by such defects can only be observed by localised techniques, since they do not represent the bulk averaged structure. Investigating such local

Cage-like microstructures via sequential Ugi reactions in aqueous emulsions

• Rita S. Alqubelat,
• Yaroslava A. Menzorova and
• Maxim A. Mironov

Beilstein J. Org. Chem. 2024, 20, 2078–2083, doi:10.3762/bjoc.20.179

• contrast image. In turn, removal of the solvent was possible only after cross-linking since otherwise, the structure would have collapsed upon drying. Therefore, a second Ugi reaction was carried out after the particles had been deposited on the surface of the toluene droplets. Thus, we carried out

• colloidal particles on the formation of the surface in Pickering emulsions, we varied the conditions for their preparation. Specifically, we increased or decreased the cross-linking density using the Ugi reaction at the first (formation of colloidal particles) and second stages of the process (formation of

• a cage-like structure on the surface of emulsion droplets). Thus, when the amount of cross-linking agent at the second stage was halved to 5 mol % relative to chitosan, less durable microspheres were obtained. When the solvent was removed, they opened up, forming a cap-like structure (Figure 4A). An

Long oligodeoxynucleotides: chemical synthesis, isolation via catching-by-polymerization, verification via sequencing, and gene expression demonstration

• Yipeng Yin,
• Reed Arneson,
• Alexander Apostle,
• Adikari M. D. N. Eriyagama,
• Komal Chillar,
• Emma Burke,
• Martina Jahfetson,
• Yinan Yuan and
• Shiyue Fang

Beilstein J. Org. Chem. 2023, 19, 1957–1965, doi:10.3762/bjoc.19.146

• monomers N,N-dimethylacrylamide and sodium acrylate, and the cross-linking agent N,N'-methylenebisacrylamide were added, and the polymerization was initiated with ammonium persulfate and N,N,N',N'-tetramethylethylenediamine (TMEDA). The full-length sequence 3 was co-polymerized into the polymer 5, and

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• high refractive-index polymers. A common approach is to incorporate atoms or groups with high polarizability and sulfur is a typical constituent with high molar refractivity and is widely used in optical polymers. For example, Bhagat et al. [84] produced polymers with high cross-linking density and

• subsequent cross-linking. Scheme 1 redrawn from [3]. (A) Structure of typical urushiol in Chinese lacquer, and (B) schematic process of laccase-catalyzed oxidation polymerization of Chinese lacquer and autoxidation reaction on the long aliphatic unsaturated side chain. Scheme 2 redrawn from [9]. A) Primary

Microelectrode arrays, electrosynthesis, and the optimization of signaling on an inert, stable surface

• Kendra Drayton-White,
• Siyue Liu,
• Yu-Chia Chang,
• Sakashi Uppal and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2022, 18, 1488–1498, doi:10.3762/bjoc.18.156

• other block is used to provide a site for cross-linking the polymer in order to render the surface more stable once it is coated onto an array (the cinnamate block is used to make a polymer network through photochemical cross-linking). The use of the borate ester surface provides a tunable surface that

Peptide stapling by late-stage Suzuki–Miyaura cross-coupling

• Hendrik Gruß,
• Rebecca C. Feiner,
• Ridhiwan Mseya,
• David C. Schröder,
• Michał Jewgiński,
• Kristian M. Müller,
• Rafał Latajka,
• Antoine Marion and
• Norbert Sewald

Beilstein J. Org. Chem. 2022, 18, 1–12, doi:10.3762/bjoc.18.1

• permeability [1][2][3]. Hence, peptide-based drugs became of high interest because of their high selectivity combined with low toxicity. Cross-linking of side chain residues results in constrained conformations and can be used to stabilise α-helical secondary structures. This technique is called peptide

• + 7 for two helix turns, respectively, followed by Ru-catalysed cross-linking [7]. By this robust and reliable approach, a library of stapled peptides was generated influencing diverse α-helical dominated protein–protein interactions (PPI) spanning pathways involved in cancer, infectious diseases

• by side chain cross-linking of bromotryptophan and an organoboron moiety. Bromotryptophans are accessible by enzymatic bromination utilising cross-linked enzyme aggregates (combiCLEAs) containing an FAD-dependent tryptophan halogenase, a flavin reductase and an alcohol dehydrogenase [73][74]. For

Cryogels: recent applications in 3D-bioprinting, injectable cryogels, drug delivery, and wound healing

• Luke O. Jones,
• Leah Williams,
• Tasmin Boam,
• Martin Kalmet,
• Chidubem Oguike and
• Fiona L. Hatton

Beilstein J. Org. Chem. 2021, 17, 2553–2569, doi:10.3762/bjoc.17.171

• hydrogel network formation via chemical cross-linking of starPEG and heparin at 4 °C and pH 8. The initial tests were reported to be a success with rapid and efficient transport of nutrients and therapeutic bsAbs via the interconnected macropores, however, more testing is required on its effects on long

Exfoliated black phosphorous-mediated CuAAC chemistry for organic and macromolecular synthesis under white LED and near-IR irradiation

• Azra Kocaarslan,
• Zafer Eroglu,
• Önder Metin and
• Yusuf Yagci

Beilstein J. Org. Chem. 2021, 17, 2477–2487, doi:10.3762/bjoc.17.164

• chain-end functionalization, block copolymer formation of structurally different polymers and cross-linking polymerization can successfully be achieved by using suitably selected click components. This new method would dramatically extend the applications of photoinduced CuAAC reactions, particularly

Highly regio- and stereoselective phosphinylphosphination of terminal alkynes with tetraphenyldiphosphine monoxide under radical conditions

• Dat Phuc Tran,
• Yuki Sato,
• Yuki Yamamoto,
• Shin-ichi Kawaguchi,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 866–872, doi:10.3762/bjoc.17.72

• as a monodentate ligand for mononuclear complexes, but it is highly attractive because a hierarchical structure can be constructed by cross-linking between two metals [24][25][26]. Considering the characteristics of the coordination form between the (E)- and (Z)-isomers, the development of a

Molecular basis for protein–protein interactions

• Brandon Charles Seychell and
• Tobias Beck

Beilstein J. Org. Chem. 2021, 17, 1–10, doi:10.3762/bjoc.17.1

• determine the amino acid sequences at the PPIs site. Examples include protein painting [22] and chemical cross-linking [23], hydrogen–deuterium exchange mass spectrometry (HDXMS) [24], and fast photochemical oxidation of proteins [25]. In protein painting, small-molecular dyes are introduced to protein

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• from our own group include the synthesis of a polystyrene gel with a photocatalytic cross-linking monomer, 4,7-bis(4-vinylphenyl)benzo[c][1,2,5]thiadiazole (St-BTZ) [47]. Additionally, we showed the direct synthesis of a BODIPY photocatalyst as a postsynthetic modification to an aldehyde-functionalised

Carbazole-functionalized hyper-cross-linked polymers for CO₂ uptake based on Friedel–Crafts polymerization on 9-phenylcarbazole

• Dandan Fang,
• Xiaodong Li,
• Meishuai Zou,
• Xiaoyan Guo and
• Aijuan Zhang

Beilstein J. Org. Chem. 2019, 15, 2856–2863, doi:10.3762/bjoc.15.279

• , 0.6 cm3 g−1) [20][33]. This may be the result of that excessive temperature caused excessive crosslink at the beginning of the reaction, the plethora network cocooned a part of the reaction center, and prevented it from further cross-linking (micropores), hence it formed macropores. All that indicated

Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission

• Lorenzo Sansalone,
• Jun Zhao,
• Matthew T. Richers and
• Graham C. R. Ellis-Davies

Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274

• activation with cycles of violet and green light. Due to the very long-lived metastable cis configuration, 4FAB in vivo use could be of great promise for long term biological studies. Further chemical functionalization of this 4FAB probe with a maleimide functionality allowed clean cross-linking with

Reversible end-to-end assembly of selectively functionalized gold nanorods by light-responsive arylazopyrazole–cyclodextrin interaction

• Maximilian Niehues,
• Patricia Tegeder and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2019, 15, 1407–1415, doi:10.3762/bjoc.15.140

• ). Even upon addition of rather high concentrations of mAAP (100 µM) no strong shift can be observed by UV–vis spectroscopy, indicating that supramolecular cross-linking is essential for end-to-end assembly of the AuNR. Conclusion In summary, we reported a supramolecular system based on the reversible

Mechanochemical synthesis of hyper-crosslinked polymers: influences on their pore structure and adsorption behaviour for organic vapors

• Sven Grätz,
• Sebastian Zink,
• Hanna Kraffczyk,
• Marcus Rose and
• Lars Borchardt

Beilstein J. Org. Chem. 2019, 15, 1154–1161, doi:10.3762/bjoc.15.112

• is shifted to 885 cm−1 hinting towards one isolated hydrogen atom which further confirms the cross-linking between the monomers. The creation of these aliphatic connections is also evident based on the appearance of vibrations around 1400 cm−1 [43]. As reported in the literature for the solvent-based

• contents below the limit of detection (Supporting Information File 1, Figure S3). Scattering electron microscopy also revealed an agglomerated morphology of the samples (Supporting Information File 1, Figure S4). After successfully establishing the occurrence of the cross-linking reaction and investigating

Stereo- and regioselective hydroboration of 1-exo-methylene pyranoses: discovery of aryltriazolylmethyl C-galactopyranosides as selective galectin-1 inhibitors

• Alexander Dahlqvist,
• Axel Furevi,
• Niklas Warlin,
• Hakon Leffler and
• Ulf J. Nilsson

Beilstein J. Org. Chem. 2019, 15, 1046–1060, doi:10.3762/bjoc.15.102

• ]. Galectin-1 has a marked preference for binding N-linked glycans, while galectin-3 binds both O-linked and N-linked glycans [5]. Galectins play many biological roles in the body and one important and well-understood function is the cross-linking of cell-surface glycoproteins through binding to O and N

Diaminoterephthalate–α-lipoic acid conjugates with fluorinated residues

• Leon Buschbeck,
• Aleksandra Markovic,
• Gunther Wittstock and
• Jens Christoffers

Beilstein J. Org. Chem. 2019, 15, 981–991, doi:10.3762/bjoc.15.96

• example for an application in biochemistry, Figure 1 shows a compound with cyclooctyne and maleimide as functional units. It was used as a "turn-on" fluorescence probe for cross-linking proteins [13]. The highly reactive cyclooctyne residue undergoes 1,3-dipolar cycloadditions with organoazides (copper

Synthesis of polydicyclopentadiene using the Cp₂TiCl₂/Et₂AlCl catalytic system and thin-layer oxidation of the polymer in air

• Zhargolma B. Bazarova,
• Ludmila S. Soroka,
• Alex A. Lyapkov,
• Мekhman S. Yusubov and
• Francis Verpoort

Beilstein J. Org. Chem. 2019, 15, 733–745, doi:10.3762/bjoc.15.69

• and can be determined by the increase of carbonyl and hydroxyl adsorption bands in infrared spectra. Along with oxidation, cross-linking processes occur in polymers, which lead to a change in physical parameters of the layers, and more precisely to a decrease in the permeability of atmospheric oxygen

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• (e.g., 105, 106) [93]. The cross-linking of the two amino acids by metathesis results in a more rigid and stabilized alpha helix (products 107 and 108, Scheme 23). Although the reaction cannot be classified as aqueous metathesis (the reaction is carried out in CHCl3 and the peptide remains attached to

Targeting the Pseudomonas quinolone signal quorum sensing system for the discovery of novel anti-infective pathoblockers

• Christian Schütz and
• Martin Empting

Beilstein J. Org. Chem. 2018, 14, 2627–2645, doi:10.3762/bjoc.14.241

• mutation experiments [79]. Moreover an in vivo cross-linking assay of full-length PqsR and a corresponding I68F mutant was carried out leading to the suggestion that upon binding of M64 the protein stability might be increased. Based on these results it was proposed that M64 induces a change in

Nucleoside macrocycles formed by intramolecular click reaction: efficient cyclization of pyrimidine nucleosides decorated with 5'-azido residues and 5-octadiynyl side chains

• Jiang Liu,
• Peter Leonard,
• Sebastian L. Müller,
• Constantin Daniliuc and
• Frank Seela

Beilstein J. Org. Chem. 2018, 14, 2404–2410, doi:10.3762/bjoc.14.217

• ’-azido-2’,5’-dideoxycytidine 2. Earlier, the nucleoside precursor 1 was used for DNA cross-linking and labelling [36]. The unprotected nucleoside 1 was treated with equimolar amounts of carbon tetrabromide and triphenylphosphine and a five-fold excess of sodium azide to obtain the azide derivative 2 (37

Investigation of the electrophilic reactivity of the biologically active marine sesquiterpenoid onchidal and model compounds

• Melissa M. Cadelis and
• Brent R. Copp

Beilstein J. Org. Chem. 2018, 14, 2229–2235, doi:10.3762/bjoc.14.197

• model protein lysozyme, forming covalent adducts and leading to protein cross-linking. These results provide preliminary evidence supporting the molecular mechanism of biological activity exhibited by onchidal. Keywords: dialdehyde; lysozyme; mollusc; onchidal; pyrrole; Introduction More than 80