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

• facilitate various modifications, including labeling, crosslinking, and the creation of protein–drug conjugates. The incorporation of photoredox strategies has facilitated the synthesis of complex protein architectures, enabling precise control over conjugation sites and degrees of modification. The number

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

• preQ1 congeners into oligonucleotide strands at specific recognition sites. In addition, the potential of modified preQ1 for protein enzyme-independent RNA labeling has also been demonstrated [12][17]. In a recent study [4], sequence-specific RNA–small molecule crosslinking (Scheme 1B) was achieved in

• highly electrophilic warheads otherwise typically employed in RNA-small molecule crosslinking [18][19][20][21]. Instead, primary alkyl halides (or mesylates, Scheme 1, in particular compounds 3a, 3b and 4c) were found to be potent yet mild alkylators that minimize off-target reactivity, while providing

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

• consists of the rotaxane crosslinking structure, as a tough material or ultra-stretchable/swelling polymer [79][80]. A typical slide ring gel has a network structure of polyrotaxane, which consists of a linear polymer chain like PEG and many α-CD rings on it, meaning that the crosslinking points are made

• of 8 shaped two CD rings movable along the polymer main chains. Thus, the applied stress can be distributed to the entire material by the movement of the crosslinking points to avoid a stress concentration, leading to a higher toughness than the conventional materials. Since a lot of existing review

• a major content of the material, Takata and co-workers developed the rotaxane crosslinker, which can be integrated as a small content on vinyl polymer synthesis to afford vinyl polymers having a certain domain of polyrotaxane crosslinking points (Figure 14) [84]. In this system, the crosslinker was

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• range of polymers [1]. They are also applied as curing, hardening and crosslinking agents [2]. Global demand for organic peroxides is expected to increase as the use of engineered plastics increases and production capacity is expanded. In addition, the need for polymers is expected to increase due to

Improved deconvolution of natural products’ protein targets using diagnostic ions from chemical proteomics linkers

• Andreas Wiest and
• Pavel Kielkowski

Beilstein J. Org. Chem. 2024, 20, 2323–2341, doi:10.3762/bjoc.20.199

• of mostly used photo-crosslinking groups. B) Mass spectrometry properties of proteins PTMs, which relate to probe–protein conjugates. C) General concept utilizing linkers to improve searches for protein–probe interactions. Direct and indirect approach to identify protein targets and representative

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• introduced into octadehydrodibenzo[12]annulene. In this report, the synthesis of new octadehydrodibenzo[12]annulene derivatives, regioselective double addition of organic azides, and an application to crosslinking polymers are described. Keywords: annulene; click chemistry; polymerization; strain-promoted

• ], and crosslinked polymers [14][15][16][17]. Since crosslinking polymers requires high reaction efficiency under mild conditions, developing such reactions is crucial. We previously reported the regioselective double azide addition to octadehydrodibenzo[12]annulene with hexyloxy substituents (DBA-OHex

• , the double azide addition reaction was applied to polymer crosslinking and the mechanical properties of the self-standing polymer films were compared. Results and Discussion Strain-promoted azide–alkyne cycloaddition Octadehydrodibenzo[12]annulene (DBA) with electron-withdrawing carbonyl substituents

Organic electron transport materials

• Joseph Cameron and
• Peter J. Skabara

Beilstein J. Org. Chem. 2024, 20, 672–674, doi:10.3762/bjoc.20.60

• soluble in ethyl acetate, a green solvent, and solution-processed for PM6:Y6 bulk-heterojunction solar cells with power conversion efficiency > 13% [6]. In addition to orthogonal processing, it has been shown that treatment with base [7] or photo-crosslinking [8] can insolubilise solution-processed layers

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

• employed technique for industrial production of polymeric materials, and other polymer synthesis involving a radical process. Post-polymerization modification, including polymer crosslinking and polymer surface modification, is the key process that introduces functionality and practicality to polymeric

• constantly acquire new inspirations from organic chemists. Dialogues on radical chemistry between the two communities will deepen the understanding of the two fields and benefit the humanity. Keywords: crosslinking; polymer surface modification; post-polymerization modification; radical chemistry; radical

• used in post-polymerization modification, including chemical crosslinking of polymers and polymer surface modification. Radicals are powerful tools for post-polymerization processes because of their exceptional reactivity. In contrast to the previous sections, we set the topic of section 4 on the

Preparation of β-cyclodextrin/polysaccharide foams using saponin

• Max Petitjean and
• José Ramón Isasi

Beilstein J. Org. Chem. 2023, 19, 78–88, doi:10.3762/bjoc.19.7

• carbon has been developed by Ma et al. [26], by the production of chitosan–saponin gels thanks to glutaraldehyde crosslinking. After adding potassium hydroxide, they freeze-dried the material and pyrolyzed the product. The resulting material possess a high absorption capacity of methylene blue, thanks to

• molecules into the cavity of the glycoside micelles should be taken into account. Our main goal in this part of the study is to guarantee that the prepared foams remain stable at least until the crosslinking reaction takes place. Once the six experimental synthetic paths were set (see Experimental section

• absence of saponin, by increasing the reaction time from 20 to 45 min (samples 20Pow and 45Pow, respectively), the yield will increase due to a higher crosslinking efficiency of the solventless procedure [38]. A mixture dissolved in water and then freeze-dried (sample 45Liq*) shows a better yield

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

• properties Cryogels are macroporous hydrogels with interconnected porosity, with high swelling capacities and large surface areas. Ultimately, many of the final cryogel properties are dependent on the choice of polymer/monomer composition used. However, other factors such as crosslinking, pore size, wall

• mechanical and thermal properties of the cryogel. Mechanical properties are mainly influenced by porosity and degree of crosslinking, while crosslinking also influences biocompatibility and degradability. In chemically crosslinked cryogels the mechanical properties can be influenced by the degree of

• crosslinking (ratio of monomer to crosslinking agent), while the degree of crosslinking is tuned in physically crosslinked cryogels by varying the number of freeze–thaw cycles. Pore size, wall thickness, and wall density are of significant importance for cryogels properties [16]. Thicker walls and higher wall

Post-functionalization of drug-loaded nanoparticles prepared by polymerization-induced self-assembly (PISA) with mitochondria targeting ligands

• Janina-Miriam Noy,
• Fan Chen and
• Martina Stenzel

Beilstein J. Org. Chem. 2021, 17, 2302–2314, doi:10.3762/bjoc.17.148

• proliferation of human synovial sarcoma SW982 cells (Figure 7). All four PISA particles displayed an enhanced cytotoxicity compared to free PENAO using SW982. While PENAO’s cytotoxicity arises mainly from crosslinking two cysteine loops in the mitochondrial ANT protein, the here employed systems seem to not

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

• influence of grafting density, degree of crosslinking or branching as well as the substrate’s influence on the UCST phase transition of grafted polymers. Moreover, for polymers in solution, a generalized thermodynamic description and a standardized characterization of the macroscopic effects via

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

• underexplored technology [131]. Chemically reactive crosslinking PNA nucleobases: PNA has become a highly useful probe for detection of nucleic acids. Not surprisingly, chemists have developed reactive nucleobases for covalently crosslinking PNA and nucleic acid targets. 4-Amino-6-oxo-2-vinylpyrimidine (AOVP

• , Figure 8), a chemically reactive mimic of cytosine, exhibited selective crosslinking reactivity with thymine in DNA when incorporated at the terminal position of a PNA probe [132]. Interestingly, the activity of the crosslinking reaction was lower in RNA. Because AOVP functional groups do not match well

• any Watson–Crick base pairing scheme, AOVP lowered the stability of PNA duplexes with complementary DNA and RNA [132]. Similarly, vinyl-modified purine (AVP) effectively crosslinked with thymine in DNA and with uracil in RNA. The crosslinking resulted in inhibition of Dicer processing of microRNA

Supramolecular polymerization of sulfated dendritic peptide amphiphiles into multivalent L-selectin binders

• David Straßburger,
• Svenja Herziger,
• Katharina Huth,
• Moritz Urschbach,
• Rainer Haag and
• Pol Besenius

Beilstein J. Org. Chem. 2021, 17, 97–104, doi:10.3762/bjoc.17.10

• acid as capping reagent for the synthesized oligopeptide on the resin. To maintain orthogonal functionalities a resin-bound diamine was deployed as starting point to start off the oligopeptide synthesis. A low loading of the resin (0.16 mmol/g) was important to prevent crosslinking during the reaction

Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)–dipicolylamine complexes

• Lena Reinke,
• Julia Bartl,
• Marcus Koch and
• Stefan Kubik

Beilstein J. Org. Chem. 2020, 16, 2687–2700, doi:10.3762/bjoc.16.219

• )–dipicolylamine complexes beyond 25% had a negative impact on the limit of detection and the optical response. Transmission electron microscopy provided evidence that the changes of the nanoparticle properties observed in the presence of the phosphates were due to a nanoparticle crosslinking, consistent with the

• conformational reorganization of the linker connecting the chromophore with the surface. The likely most frequently used strategy of analyte detection relies on the color change of AuNP solutions resulting from analyte-induced nanoparticle crosslinking. Depending on whether soluble or insoluble aggregates are

• binding of these anions to the immobilized receptor units strengthened their interaction with a simultaneously present bis(imidazolium) ion, which in turn caused nanoparticle crosslinking [16][17]. Our group recently showed that a mixed monolayer-protected AuNP containing solubilizing triethylene glycol

Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• crosslinked polymers made up of cyclodextrins. The reactive hydroxy groups of CDs allow them to act as multifunctional monomers capable of crosslinking to bi- or multifunctional chemicals. The most common NS synthetic pathway consists in dissolving the chosen CD and an appropriate crosslinker in organic polar

• , and rhodamine B) and the still reactive imidazoyl carbonyl group of the NS. Keywords: β-cyclodextrin; ball-milling; crosslinking; green chemistry; mechanochemistry; nanosponges; Introduction The research in the fields of nanomedicine and nanotechnology has nowadays become predominant

• allow them to act as polyfunctional monomers, permitting the crosslinking with bi- or multifunctional chemicals, such as dianhydrides, diisocyanates, diepoxides, and dicarboxylic acids, etc. The polarity and size of the polymer network can be easily tuned by varying the type of the crosslinker and

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

• , as well as the C/N ratio, which has been confirmed by elemental analysis. Elemental analyses were measured to compare the degree of crosslinking of P1–P11 (Table 3), because the C/N ratio of the polymer will increase as the degree of crosslinking increases. The effect of molar ratio of cross-linker

• surface area of P1 was due to the less FDA which reduced the crosslinking density. Largely exaltation of BET surface area from P1 to P3 was due to the increasing FDA/9-PCz ratio improved the crosslinking density which could be confirmed by the increasing C/N ratio (Table 3). However, further increasing

• the molar ratio of FDA to 9-PCz could not result in a higher BET specific surface area, because the high steric hindrance prevented further crosslinking reaction [39], the raised C/N ratio (Table 3) maybe because of the tail end groups of FDA. The BET specific surface area of P3 was much higher than

Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions

• László Jicsinszky,
• Federica Calsolaro,
• Katia Martina,
• Fabio Bucciol,
• Maela Manzoli and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145

• provide (2-hydroxy)propyl-CDs (HPCDs) that are commonly used in pharmaceutical formulations and household products. Furthermore, a class of non-hydrolysable, soluble and insoluble CD polymers (CDP) can be prepared by crosslinking CDs with epichlorohydrin or 1,2:3,4-diepoxybutane. These are the oldest and

• contains a considerable amount of the glycidyl (2,3-dihydroxypropyl) sidechain in the solution reaction instead of the crosslinking ether units. It is known that the reaction can be directed to the glycidyl CD derivatives instead of polymerisation by varying the conditions [45][46][47]. Centrifugation of

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

• , they are formed by a non-directed aromatic substitution (Friedel–Crafts alkylation) either by intramolecular functional groups or using external crosslinkers. These reactions yield very high crosslinking degrees in amorphous framework structures and hence, enable highest specific BET (Brunauer–Emmett

• trifluoromethanesulfonic acid or sulfuric acid was developed yielding basically the same polymer but avoiding residual traces of the metal [11]. These synthetic pathways often afford a gel from the dissolved monomers upon the crosslinking that is subsequently washed and dried with a significant volume loss. Still, a high

• synthesis of several porous materials [21][22][23][24][25][26][27][28][29] and polymers [30][31][32][33][34][35][36][37][38][39][40][41][42]. In this contribution, we employed mechanochemistry for a protocol for the solvent-free crosslinking of HCP (Figure 1). This is supported by an investigation of

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

• cationic polymerization, are characterized by certain disadvantages. They have a low molecular weight, a fairly rigid structure of the polymer chains due to crosslinking processes occurring during polymerization. In addition, DCPD polymers obtained from "hard" catalytic systems, such as TiCl4, SnCl4, etc

• loses its transparency and becomes dark as a function of time when stored in air. This is attributed to the formation of crosslinking in the polymer structure and oxidation of unsaturated bonds, which are excessively present in the polymer structure [12][13][14]. Oxidation of thin PDCPD films in air

• , crosslinking of polymer chains occurs along with oxidation processes, which leads to compaction of the polymer structure and reduction of the mobility of the polymer chains. This adversely affects the rate of penetration of air oxygen through the layer of the structured polymer. As a result, physical

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• 2900 cm−1 and 3400 cm−1 were the evidence of phenylic C–H bond and N–H stretching of carbazole, respectively. Peaks at 1022 cm−1 and 1039 cm−1 corresponded to additional crosslinking during the sulfonation process. The catalyst was investigated by BET, SEM, TEM, and TGA-DTA, as well. The BET surface

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

• % yield of adducts, respectively, with 17 requiring 72 hour incubation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used to look for the presence of protein crosslinking arising from the incubation of dialdehydes 11 and 15 and enol acetate 13 with lysozyme. Bands corresponding

• to dimers (28 kDa) were evident for both the n-pentyl and cyclohexylmethyl dialdehydes, with a faint band at 50 kDa also evident in the n-pentyl dialdehyde incubation reaction, indicating the presence of lysozyme trimers (Figure 6). No crosslinking was detected for enol acetate 13, likely due to its

• apparent with the lysine-rich enzyme hen egg white lysozyme, with onchidal (6) and model compounds 11–13 and 15–17 affording pyrrole adducts of the enzyme that were detected by (+)-ESIMS. The more reactive dialdehydes were also found to lead to protein crosslinking with formation of lysozyme dimers and

Diazirine-functionalized mannosides for photoaffinity labeling: trouble with FimH

• Femke Beiroth,
• Tomas Koudelka,
• Thorsten Overath,
• Stefan D. Knight,
• Andreas Tholey and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1890–1900, doi:10.3762/bjoc.14.163

• -functionalized mannosides as high-affinity FimH ligands and performed an extensive study on photo-crosslinking of the best ligand (mannoside 3) with a series of model peptides and FimH. Notably, we have employed high-performance mass spectrometry to be able to detect radiation results with the highest possible

• ]), we could not observe labeled products by fluorine NMR. This is presumably due to the low labeling efficiency as in the literature 19F NMR spectra were obtained with proteins having 19F-labeled amino acids incorporated [30]. Disappointingly, instead of crosslinking, we observed two different other

• could support the desired crosslinking reaction. Thus, the high affinity of 3 for FimH would facilitate insertion of the carbene, which is formed after irradiation, into OH, NH or CH groups, respectively, in proximity of the lectin’s carbohydrate binding site. We were hoping that after our initial

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• the diffusion through the membrane was not possible. Moreover, the crosslinking enabled stabilization of the enzymes, which remained active also after 10 days. Polymersome nanoreactors have also been used to perform many types of non-enzymatic catalytic reactions, such as the proline-catalyzed

Carbohydrate inhibitors of cholera toxin

• Vajinder Kumar and
• W. Bruce Turnbull

Beilstein J. Org. Chem. 2018, 14, 484–498, doi:10.3762/bjoc.14.34

• induced upon crosslinking the gold nanoparticles with CTB or LTB as a strategy for detecting the bacterial toxins. Conclusion Cholera and related diseases caused by other bacterial toxins remain a substantial threat to society. This challenge, and a molecular understanding of the basis of toxin action