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Search for "immobilization" in Full Text gives 100 result(s) in Beilstein Journal of Organic Chemistry.
Nanoreactors for green catalysis
Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61
- -coupling reactions. Catalytic activity was compared to the activity of the freshly prepared free catalyst, and the palladium entrapment did not affect either the conversion or the yields of the reaction [28]. The catalyst immobilization also allowed facile Pd removal from the final product and catalyst
- hydrophobic and aqueous compartments, they are especially useful for the immobilization of different catalysts, such as organocatalysts and enzymes that require different microenvironments for their optimal performance. 3. Covalent systems 3.1. Dendrimers Dendrimers are a class of highly branched molecules
Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor
Beilstein J. Org. Chem. 2018, 14, 697–703, doi:10.3762/bjoc.14.58
- biocatalytic processes have been reported in flow reactors [19], mostly advocating easier process intensification in combination with enzyme immobilization [20][21][22][23]. Also the higher oxygen-transfer rates in flow reactions compared to batch reactions have been emphasised by several groups. Here, reactor
Enzyme-free genetic copying of DNA and RNA sequences
Beilstein J. Org. Chem. 2018, 14, 603–617, doi:10.3762/bjoc.14.47
- , if one wants to work with any given sequence context and all four bases (A/C/G/U). The second option is to remove the spent monomers when their concentration reaches a critical threshold. This requires immobilization of the primer–template complex and washing [32][47] or removal of hydrolyzed
- features. Copying on solid support As mentioned above, one option to avoid stalling of primer extension reactions is to perform them on solid support. For RNA, the immobilization of the primer–template duplex was achieved by employing a biotinylated capture strand that was bound to streptavidin-coated
Latest development in the synthesis of ursodeoxycholic acid (UDCA): a critical review
Beilstein J. Org. Chem. 2018, 14, 470–483, doi:10.3762/bjoc.14.33
- immobilization of enzymes [93]. The first system shows high stability (enzymes in the membrane reactor have a half-life of 1–2 weeks) and the biocatalysts can be reused for eight cycles of conversions. On the other hand, immobilized enzymes show a higher productivity (88.5 vs 8 g L−1 d−1) despite the fact that
- range of 5–15 mM [101][102][103][104]. Accordingly, the addition of co-solvents increases the CMC of bile acids and the availability of monomers in solution. Notably, HSDHs are relatively stable and active in 10–20% methanol. Moreover, the immobilization of the enzyme can provide a higher stability to
Preparation of trinucleotide phosphoramidites as synthons for the synthesis of gene libraries
Beilstein J. Org. Chem. 2018, 14, 397–406, doi:10.3762/bjoc.14.28
- account that the 3'-start nucleoside is required to be linked to the solid phase in a way that allows the cleavage of the trimer from the solid support, but leaves all other protecting groups intact. Therefore, the routinely used succinate linkage for immobilization of the start nucleotide cannot be used
Phosphonic acid: preparation and applications
Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219
- dots [107] and used as anchoring group for dye-sensitized solar cells [108][109][110] or for the immobilization of organocatalyst [111][112]. Phosphonic acid was also used for coating superparamagnetic iron oxide (e.g., magnetite) assessed as contrast agent in magnetic resonance imaging [113] or to
- conceive a red/ox catalyst that can be magnetically separated from the reaction media [114]. The immobilization of phosphonic acid can be also achieved by supramolecular interaction between the support and the phosphonic acid moiety leading to heterosupramolecular structures [115]. Some phosphonic acids
Synthesis of oligonucleotides on a soluble support
Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134
- applied to the synthesis of a PEG-conjugated 12-mer antisense ODN [53] and a 13-mer purine-rich triple-helix forming sequence [54]. Immobilization of the 3´-terminal nucleosides via a succinyl linker was, however, replaced by direct phosphoramidite coupling to the terminal OH of PEG, which gave a stable
Towards open-ended evolution in self-replicating molecular systems
Beilstein J. Org. Chem. 2017, 13, 1189–1203, doi:10.3762/bjoc.13.118
- instead of parabolic growth of the replicators. A successful approach to overcoming product inhibition involves the immobilization of the template molecules by fixing them onto a solid support. This approach was partially inspired by the notion that surfaces of minerals might have played a major role in
Glyco-gold nanoparticles: synthesis and applications
Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100
- procedure for the immobilization of carbohydrates on the nanoparticles surface [27]. The AuNPs were firstly coated with a PFPA-thiol monolayer via a ligand-exchange reaction, then carbohydrates were immobilized by means of a photocoupling reaction. Glyco-gold nanoparticles: design and structural properties
- application showed for the first time the immobilization of AuNPs on the endface of an optical fiber by means of thio-chemistry [82]. A second layer of glycosyl residues (maltose or lactose) containing thioctic acid was covalently linked on supported AuNPs, affording the fiber-type “Sugar Chips” (Figure 6
Continuous-flow processes for the catalytic partial hydrogenation reaction of alkynes
Beilstein J. Org. Chem. 2017, 13, 734–754, doi:10.3762/bjoc.13.73
- onto an open-cell macroporous (10 μm pore size), polymeric borate monolith, that was grown in situ within the walls of a commercial, tubular glass reactor (MonoBor, reactor volume 176 μL, Figure 5) [133]. The monolithic support was specifically designed to allow for the immobilization of Pd particles
Sulfamide chemistry applied to the functionalization of self-assembled monolayers on gold surfaces
Beilstein J. Org. Chem. 2017, 13, 648–658, doi:10.3762/bjoc.13.64
- have been investigated for the immobilization of a target molecule through a reaction with the terminal groups of the SAMs. The most common methods to covalently functionalize these materials involve the Huisgen cycloaddition between an azide and an alkyne [8][9], Thiol-Michael addition [10][11], amide
- formation [12][13][14], Diels–Alder reaction [15][16] or the imine/oxime condensation [17][18]. These reactions tend to produce strong covalent interactions between the surface and the molecules in solution which ensure a stable immobilization. One limitation of the covalent strategy lies in the
Transition-metal-catalyzed synthesis of phenols and aryl thiols
Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58
- yields. In 2015, Ghorbani-Choghamarani and co-workers designed a new type of nanocatalyst MCM-41-dzt-Pd through the immobilization of Pd(OAc)2 on the surface of dithizone(dzt)-functionalized mesoporous MCM-41 (Scheme 6) [26]. The developed catalyst was able to convert aryl halides to the corresponding
Versatile synthesis of end-reactive polyrotaxanes applicable to fabrication of supramolecular biomaterials
Beilstein J. Org. Chem. 2016, 12, 2883–2892, doi:10.3762/bjoc.12.287
- fluorescence imaging Terminal reactive groups in the PRXs can be utilized in various biomaterials applications, such as the fabrication of cross-linked materials (e.g., hydrogels) [29], direct surface immobilization onto alkyne-immobilized surfaces [30], and the modification of other functional molecules for
- click reactions, including ligand molecules for active targeting, radioactive molecules for in vivo imaging, hydrophobic polymers for the surface immobilization of PRXs, and hydrophilic polymers for acquiring water solubility. Accordingly, the azide group-terminated end-reactive 4a and 4b are expected
- to be useful candidates in the fabrication or functionalization of supramolecular biomaterials, such as cross-linked hydrogels, surface immobilization, and drug delivery carriers for biomolecules [6]. Further studies relating to the biomaterials applications of azide group-terminated PRXs are
Towards the development of continuous, organocatalytic, and stereoselective reactions in deep eutectic solvents
Beilstein J. Org. Chem. 2016, 12, 2620–2626, doi:10.3762/bjoc.12.258
- strategy aimed at positively realizing the recovery and the reuse of the catalyst is represented by the immobilization of the catalytic species [24][25][26][27]. Synthetic modifications of the original catalyst, however, are required in order to attach the catalyst to the material of choice. The aim of the
A self-assembled cyclodextrin nanocarrier for photoreactive squaraine
Beilstein J. Org. Chem. 2016, 12, 2535–2542, doi:10.3762/bjoc.12.248
- cyclodextrin vesicle surface. The supramolecular immobilization was monitored by using fluorescence spectroscopy and microscopy and the photochemistry of the squaraine was investigated by using absorption spectroscopy. Keywords: cyclodextrin; host–guest chemistry; photodynamic therapy; self-assembly
- applications when a well-known PS, phthalocyanine, was used to decorate the cyclodextrin vesicles [37][38]. The immobilization led to an increased photoactivity of the phthalocyanines due to suppression of aggregation and inactivation of the PS at the surface of the CDVs. In this contribution we show that
- for the CDV without affecting its photochemistry. In addition, it is expected that the aggregation of squaraine will be supressed by immobilization at the CDV surface. Ultimately, the photoactive squaraine can be combined with other functional guests, such as targeting units and tracers, to further
Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates
Beilstein J. Org. Chem. 2016, 12, 1911–1924, doi:10.3762/bjoc.12.181
- therefore imperative not only to limit their release to the environment, but also for economic reasons. One strategy to cope with the recycling issue is based on the immobilization of ionic liquids onto solid supports. In the specific field of transesterification reactions, supported ionic liquid (SILs
Highly stable and reusable immobilized formate dehydrogenases: Promising biocatalysts for in situ regeneration of NADH
Beilstein J. Org. Chem. 2016, 12, 271–277, doi:10.3762/bjoc.12.29
- modified with ethylenediamine and then activated with glutaraldehyde (FDHIGLU), and Immobead 150 support functionalized with aldehyde groups (FDHIALD). The highest immobilization yield and activity yield were obtained as 90% and 132%, respectively when Immobead 150 functionalized with aldehyde groups was
- [14] and lack of reusability, therefore, the immobilization of FDH has been of increasing interest in the recent years. For example, Netto et al. [15] immobilized FDH from Candida boidinii on three different magnetic supports and the results showed that conversion rates and recycling values were
- changed depending on the support used for immobilization. Bolivar et al. [16] used different strategies for the immobilization of FDH from Candida boidinii and reported that the stabilization factors were changed depending on the immobilization protocol. Kim et al. [17] immobilized FDH from Candida
Ru complexes of Hoveyda–Grubbs type immobilized on lamellar zeolites: activity in olefin metathesis reactions
Beilstein J. Org. Chem. 2015, 11, 2087–2096, doi:10.3762/bjoc.11.225
- revealed that during immobilization ion exchange between Hoveyda–Grubbs type catalyst and zeolitic support occurred in the case of Cl− counter anion; in contrast, PF6− counter anion underwent partial decomposition. Keywords: Hoveyda–Grubbs type catalyst; hybrid catalysts; lamellar zeolites; non-covalent
- immobilization; olefin metathesis; Introduction Immobilization of Ru alkylidene complexes (Grubbs and Hoveyda–Grubbs type catalysts) on siliceous supports represents a successful way to highly active, selective, and reusable metathesis catalysts [1][2][3][4]. Mesoporous molecular sieves (MCM-41, MCM-48, SBA-15
- ), with large BET areas and pore volumes, proved to be very suitable supports, due to easy attachment of bulky organometallic complexes onto silica surface ensuring rapid diffusion of reactants to the active catalytic sites [5][6][7][8][9][10][11][12]. Several strategies of immobilization have been
Impact of multivalent charge presentation on peptide–nanoparticle aggregation
Beilstein J. Org. Chem. 2015, 11, 792–803, doi:10.3762/bjoc.11.89
- immobilization of the peptide on the nanoparticle surface in multiple layers. Thus, the concentration of dissolved peptide is dramatically decreased and a CD signal can not be detected anymore. A similar effect could be described by Calzolai and coworkers using silver nanoparticles [40]. Furthermore, the minimum
Orthogonal dual-modification of proteins for the engineering of multivalent protein scaffolds
Beilstein J. Org. Chem. 2015, 11, 784–791, doi:10.3762/bjoc.11.88
- conjugated with biotin using oxime ligation, by which the protein scaffold was immobilized on a streptavidin gold chip to monitor carbohydrate–protein binding studies by surface plasmon resonance (SPR). This immobilization strategy allowed easy handling and reproducible orientation, which are notable
- improvements over the alternative active ester immobilization. Although not directly demonstrated in the current paper, our approach required considerably lower amounts of the inhibiting glycoconjugate in comparison to the reverse approach, which involves immobilization of lectin and titration of the binder
- -binding of ECL to adjacent Gal-3 proteins might occur due to the initial high immobilization level. In contrast, the non-glycosylated lipase exhibited no binding at all. To further characterize the binding efficiency, KD-values were determined by SPR measurements (for set-up see Supporting Information
Regulation of integrin and growth factor signaling in biomaterials for osteodifferentiation
Beilstein J. Org. Chem. 2015, 11, 773–783, doi:10.3762/bjoc.11.87
- stable gradients of growth factors to regulate their bioavailability [11]. This matrix-immobilization of the factors might result in long-term binding to cell surface receptors, since the binding affinity of ECM-factors is relatively weak compared to growth factor receptor interactions [8]. Moreover, the
- systems exist in both soluble and matrix-bound forms [82]. Therefore, growth factor delivery can be designed by both encapsulation and surface immobilization approaches (Figure 6). The proteins should be slowly released from the delivery systems in the former case. The latter immobilization systems have
- . For example, the immobilization or encapsulation methods, the concentration and ratio, and the distribution, i.e., spatial relationship should be optimized in biomaterials and cell therapeutics. Overall, engineering the local delivery of integrin ligands and growth factors provides powerful and
Multivalent polyglycerol supported imidazolidin-4-one organocatalysts for enantioselective Friedel–Crafts alkylations
Beilstein J. Org. Chem. 2015, 11, 730–738, doi:10.3762/bjoc.11.83
- Tommaso Pecchioli Manoj Kumar Muthyala Rainer Haag Mathias Christmann Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195 Berlin, Germany 10.3762/bjoc.11.83 Abstract The first immobilization of a MacMillan’s first generation organocatalyst onto dendritic support is
- loss of activity due to immobilization, albeit moderate enantioselectivities were observed. Moreover, easy recovery by selective precipitation allowed the reuse of the catalyst for three cycles. Keywords: Friedel–Crafts; homogeneous catalysis; hyperbranched polyglycerol; imidazolidin-4-one
- decorated dendron-hybrids [47], the presence of water was crucial for aldol and Baylis–Hillman reactions, as recently reported by Miller and Portnoy [48]. To the best of our knowledge, the immobilization of chiral organocatalysts on hyperbranched polymeric support has remained unexplored. Therefore, we
Probing multivalency in ligand–receptor-mediated adhesion of soft, biomimetic interfaces
Beilstein J. Org. Chem. 2015, 11, 720–729, doi:10.3762/bjoc.11.82
- mannose functionalization. Immobilization of ConA to glass surfaces ConA was bound to coverslips as previously described [8]. Briefly, coverslips (Ø 24 mm, ≈0.17 mm thickness) were used as glass surface (Thermo scientific, Germany) and cleaned prior to use by washing with isopropanol and piranha solution
Synthesis of tripodal catecholates and their immobilization on zinc oxide nanoparticles
Beilstein J. Org. Chem. 2015, 11, 678–686, doi:10.3762/bjoc.11.77
- anchor groups for biomedically relevant metal surfaces and nanoparticles. We report here the synthesis of new tripodal catecholates as multivalent anchor molecules for immobilization on metal surfaces and nanoparticles. The tripodal catecholates have been conjugated to various effector molecules such as
- PEG, a sulfobetaine and an adamantyl group. The potential of these conjugates has been demonstrated with the immobilization of tripodal catecholates on ZnO NPs. The results confirmed a high loading of tripodal PEG-catecholates on the particles and the formation of stable PEG layers in aqueous solution
- needs to form a stable (in most cases covalent) connection to the target surface. Various bifunctional anchors have been reported for immobilization on different materials and nanoparticles. Basically, silane derivatives are used for glass surfaces [2][3], thiols for noble metal surfaces [4
Synthesis of carbohydrate-scaffolded thymine glycoconjugates to organize multivalency
Beilstein J. Org. Chem. 2015, 11, 668–674, doi:10.3762/bjoc.11.75
- install both branches on a carbohydrate scaffold. This would allow to favour the intramolecular [2 + 2] cycloaddition over an intermolecular reaction and moreover, a multifunctional carbohydrate scaffold facilitates further ligation or immobilization, respectively, of the final molecular construct. After
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