Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study

• Yasuhiro Oishi,
• Motoharu Kitatani and
• Koichi Kusakabe

Beilstein J. Org. Chem. 2024, 20, 570–577, doi:10.3762/bjoc.20.49

• to carbon materials [2][3]. The properties and characteristics of these linker molecules are keys not only to the purpose of protein immobilization, but also to the behavior of the entire biosensor system. In oscillator-based biosensors, further adsorption on the sensor, such as viruses using antigen

• sensor chips and specifically binds to the antibody. The antigen is then detected by observing the change in the vibrational frequency before and after the injection of the antigen. The immobilization of a protein using a PASE linker on carbon nanotube [1], graphite [4], and graphene [5] has been

• ]. Various biosensors have already been developed, many of which require immobilization of antibody proteins on graphene surface. Therefore, protein capture by linkers is used in a relatively large number of sensors. In the elastic wave measurement system, elastic waves are generated by laser irradiation and

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• of Fe3O4 nanoparticles (Scheme 15) [101][102]. This organic–inorganic hybrid material was synthesized by the immobilization of the dodecatungstovanadophosphoric acid (HPA) on TPI-Fe3O4 with N-[3-(triethoxysilyl)propyl]isonicotinamide (TPI), acting as the linker for the heterogeneous catalyst, while

• to the employment of GO–CuBr without overshadowing its applications [113]. Shirini et al. utilized the polymer poly(4-vinylpyridine) (P4VPy) for the immobilization of nanoparticles in lieu of silica, due to the strong affinity of the pyridyl group towards metals and its ability to undergo hydrogen

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• varied in their immobilization amounts, we confirmed these results in a GAG-focused array (data not shown). We thus posit a binding to internal GalNAc epitopes for the case of GAG binding, potentially mediated by several binding sites. This argument is strengthened by the observation that the highest

• . An immobilization level of 900 response units (RU) was obtained. A reference surface was always present in flow cell 1, allowing for the subtraction of bulk effects and non-specific interactions with streptavidin. The mammalian-produced CMA1 was injected in single cycle kinetic over the flow cell

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• flow systems. Accordingly, the main recycling methods rely on the immobilization of catalysts on heterogeneous supports, however, this could often lead to the deterioration of activity and/or selectivity [27]. A possible solution to avoid these drawbacks is the heterogenization of the catalyst after a

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• scavengers to facilitate liquid–solid separations inline. This approach has limitations when stoichiometric quantities of reagents or leftover reactants are to be removed, however, in case of catalytic amounts such scavengers are highly effective and widely applicable. The immobilization of catalysts

Design, synthesis, and evaluation of chiral thiophosphorus acids as organocatalysts

• Karen R. Winters and
• Jean-Luc Montchamp

Beilstein J. Org. Chem. 2022, 18, 1471–1478, doi:10.3762/bjoc.18.154

• straightforward and accomplished late-stage, to avoid carrying the chirality through multiple steps and the possible erosion of enantiomeric excesses. Preferably, both enantiomers of the CPA should also be available and immobilization of the CPA on a solid support should be possible. In this paper, we report our

• cross-coupling, and 2) immobilization on a solid support via reduction and reaction of the aniline with an electrophile such as polystyrene isocyanate. DOPO scaffold We previously reported the syntheses of both enantiomers of 8-phenyl DOPO 3 [38]. The syntheses proceed in only three steps (including the

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• one of the three ZnPor units being available for the attachment (immobilization) of an organocatalyst, we wondered about the catalytic activity of the dynamic three-component ensembles 89•(82•X) using N-methylpyrrolidine (89) as organocatalyst. For assessment, the conjugate addition of 86 and 87 was

Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid

• Jannis A. Reich,
• Miriam Aßmann,
• Kristin Hölting,
• Paul Bubenheim,
• Jürgen Kuballa and
• Andreas Liese

Beilstein J. Org. Chem. 2022, 18, 567–579, doi:10.3762/bjoc.18.59

• for the aldolase from 108 to 42 mM and 91 to 37 mM, respectively. Keywords: aldolase; continuous fixed-bed reactor; enzyme; epimerase; GlcNAc; high pressure; immobilization; ManNAc; Neu5Ac; pyruvate; Introduction In times of a pandemic, the importance of substances to enhance the human immune system

• . [27] or reviewed by Plutschack et al. [28]. In the current work pressures up to 130 MPa were achieved by using an ultrahigh-performance liquid chromatography (UHPLC) pump. Results and Discussion Immobilization For the biosynthesis of N-acetylneuraminic acid, two enzymes, the epimerase from Pedobacter

• purposes, six different carriers were used to immobilize the epimerase and aldolase (Table 1). The carriers differ in their properties (size, hydrophobicity, binding type, and porosity). The quality of immobilization was evaluated in terms of enzyme loading, activity, and reusability in repetitive batch

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

• cell proliferation and waste exchange, e.g., in a scaffold for tissue engineering applications [3]. Novel biomedical and biotechnical applications of cryogels can also be found in controlled drug delivery, carriers for cell immobilization, sensors, bioseparation, purification, and wound dressing [4][5

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

• collapses or swells depending on the temperature resulting in a reversibly switching behavior of structure and shape of the micelle. Definition and phase transition behavior of polymers grafted on flat and particular surfaces: For numerous applications, immobilization of the polymer chains is desirable. In

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles

• Bingbing Lai,
• Meng Ye,
• Ping Liu,
• Minghao Li,
• Rongxian Bai and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2888–2902, doi:10.3762/bjoc.16.238

• to the −SO3 and O−S−O stretching of the −SO3Na (or −SO3H) group [18][19]. Grafting of the FAS moiety changed the peak pattern of –SO3Na in LS-FAS material, and the immobilization of the Cu complex shifted the corresponding peaks to a higher wavenumber position, implying the successful coordination of

• spectra were further recorded, and the results confirmed the presence of Cu+ at ≈570 eV, while Cu0 at 565.6 eV [29][30][31], meaning that Cu2+ species were partially reduced during the course of immobilization. Catalytic activity of the catalysts With the catalysts in hand, we investigated their catalytic

• decreasing of the catalyst loading (Table 2, entry 6 vs entries 9 and 10). In order to utilize the residual –SO3Na groups in LS-FAS-Cu after immobilization of the Cu species, LS-FAS-Cu were further acidized by sulfuric acid solution (2 M) and denoted as LSA-FAS-Cu. The amount of –SO3H was determined through

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

• and Discussion Ligand synthesis. The ligands used in this work are depicted in Figure 1. All of them derived from lipoic acid, which was chosen as the anchor group because the immobilization of a cyclic disulfide on gold involves the formation of two Au–S bonds, causing the ligands to have a smaller

• nanoparticle surface after immobilization. Compound 2 was prepared by starting from potassium phthalimide and 1,12-dibromododecane (Scheme 2). The product resulting from this step was treated with bis(2-pyridylmethyl)amine to give a DPA derivative that was coupled to (R)-lipoic acid after deprotection to

• to address this solubility issue by increasing the fraction of the organic solvent during the exchange reaction, but the products thus obtained also did not contain immobilized 2 according to the 1H NMR spectroscopic characterization. For similar reasons, the simultaneous immobilization of (R)-1 and

Activation of pentafluoropropane isomers at a nanoscopic aluminum chlorofluoride: hydrodefluorination versus dehydrofluorination

• Maëva-Charlotte Kervarec,
• Thomas Braun,
• Mike Ahrens and
• Erhard Kemnitz

Beilstein J. Org. Chem. 2020, 16, 2623–2635, doi:10.3762/bjoc.16.213

• the above-mentioned benzene interaction. Furthermore, in the presence of silane, additional mechanistic C–F activation steps have to be considered (Scheme 5). Basically, the immobilization of silane at the Lewis-acidic surface might result in silylium-like species, which subsequently initiate the C–F

Palladium nanoparticles supported on chitin-based nanomaterials as heterogeneous catalysts for the Heck coupling reaction

• Tony Jin,
• Malickah Hicks,
• Davis Kurdyla,
• Sabahudin Hrapovic,
• Edmond Lam and
• Audrey Moores

Beilstein J. Org. Chem. 2020, 16, 2477–2483, doi:10.3762/bjoc.16.201

• for PdNP@ChNC and PdNP@ChsNCs were −13.9 and +57.9 mV, respectively. PdNP@ChsNCs were, again, far more suspendable in aqueous solution as compared to PdNP@ChNCs. TEM micrographs of PdNP@ChNC (Figure 2a) and PdNP@ChsNC (Figure 2b) confirmed complete immobilization of Pd NPs onto both the ChNC and ChsNC

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• exploited in many applications including the selective sensing of saccharides, the separation and purification of glycoproteins, and the immobilization of antibodies in microarrays [17][18][19][20][21]. However, the synthesis of boronic esters is sometimes problematic, as it often requires a fine tuning of

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

• Edgar Peris,
• Raúl Porcar,
• María Macia,
• Jesús Alcázar,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

• this leaching process, the role of the ligand and the support on the evolution of the catalytic systems should be carefully considered. It has been shown that the immobilization of Pd-catalysts or precatalysts onto supported ionic liquid-like materials can facilitate the recapture by the support of the

• mmol Cl/g,) was used as the starting material for the immobilization of N-arylimidazoles 2a and 2b, following the traditional alkylation protocol [18][19]. The preparation of these modified polymers was monitored by FT–ATR–IR, FT-Raman using a micro-spectroscopy accessory and the NBP test [20][21]. The

Design, synthesis and application of carbazole macrocycles in anion sensors

• Alo Rüütel,
• Ville Yrjänä,
• Sandip A. Kadam,
• Indrek Saar,
• Mihkel Ilisson,
• Astrid Darnell,
• Kristjan Haav,
• Tõiv Haljasorg,
• Lauri Toom,
• Johan Bobacka and
• Ivo Leito

Beilstein J. Org. Chem. 2020, 16, 1901–1914, doi:10.3762/bjoc.16.157

• the approach that was used in this study. In this case, the receptor molecule must be highly lipophilic. It is usually easier to tune the solubility of the receptor molecule than it is to add the functional groups necessary for covalent immobilization [25]. Therefore, these types of sensors are easier

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• catalysis are well-known and documented [1][2][3]. However, problems associated with catalyst recovery limit the application of homogeneous catalysts in industry and sometimes make their heterogenization necessary. Unfortunately, the immobilization of a homogeneous catalyst onto supports, such as

• -linked covalent polymeric matrixes or the destruction of catalytic centers during productive cycles can shorten the lives of the catalysts to an extent that makes the immobilization of homogeneous catalysts impractical [7]. In recent decades, novel classes of heterogeneous, porous, crystalline

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• 2000, reported for the first time, a crucial modification of a glassy carbon electrode via chemical immobilization of ᴅ-amino acid oxidase (D-AOx) as enzyme and 1-aminopropyl-1'-methyl-4,4'-dipyridinium iodide (ADPy) as electron mediator and thus prepared electrode D-AOx/ADPy/GC. Electrochemical

Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis

• Alexander F. de la Torre,
• Gabriel S. Scatena,
• Oscar Valdés,
• Daniel G. Rivera and
• Márcio W. Paixão

Beilstein J. Org. Chem. 2019, 15, 1210–1216, doi:10.3762/bjoc.15.118

• asymmetric Michael addition of n-butanal to β-nitrostyrene that was used as a model reaction. This work supports the potential of multicomponent reactions towards the assembly of catalysts and their simultaneous functionalization for immobilization. Keywords: flow chemistry; heterogeneous catalysis

• ; multicomponent reactions; organocatalysis; polyfurfuryl alcohol; Introduction The immobilization of secondary amine-based catalysts onto organic polymers and silica gel has emerged as an effective strategy that combines the power of heterogeneous and organocatalysis [1][2][3]. Asymmetric catalysis using polymer

Asymmetric synthesis of a high added value chiral amine using immobilized ω-transaminases

• Antonella Petri,
• Valeria Colonna and
• Oreste Piccolo

Beilstein J. Org. Chem. 2019, 15, 60–66, doi:10.3762/bjoc.15.6

• configuration. Recent studies have favored the application of TAs at the industrial level, so it is not surprising that they are frequently found among the enzymes designed for the large-scale synthesis of chiral amines [2][4]. Moreover, immobilization of TAs has been developed in order to increase stability

• isopropylamine as the amine donor (Scheme 1). These enzymes are covalently immobilized on an epoxyacrylate resin and offer several advantages over the native ones, especially in view of a large scale application. In addition to an enhanced stability at higher temperatures or in organic solvents, immobilization

Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands

• Veronica Paradiso,
• Chiara Costabile and
• Fabia Grisi

Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292

• immobilization on various supports, Fürstner et al. reported on the preparation of some unsymmetrical complexes containing pendant protected (105–108) and unprotected (109–111) hydroxyalkyl chains on their NHCs (Figure 20) [40]. Complex 109 was easily immobilized on functionalized silica gel and the resulting

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• progress has been achieved with chiral calix[4]arenes, there are still several opportunities for further enhancements such as catalyst design, loading and substrate scope in the reaction systems. Immobilization of these calixarene derivatives onto polymers or magnetic nanoparticles would also lead to