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Search for "linkers" in Full Text gives 176 result(s) in Beilstein Journal of Organic Chemistry.

Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials

  • Alberto Spinella,
  • Marco Russo,
  • Antonella Di Vincenzo,
  • Delia Chillura Martino and
  • Paolo Lo Meo

Beilstein J. Org. Chem. 2018, 14, 1498–1507, doi:10.3762/bjoc.14.127

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  • , V.le delle Scienze ed. 17, 90128 Palermo, Italy 10.3762/bjoc.14.127 Abstract New calixarene-based nanosponges (CaNSs), i.e., hyper-reticulated polymers constituted by calixarene monomer units joined by means of bis(1,2,3-trialzolyl)alkyl linkers, were synthesized, characterized and subjected to
  • was assessed by means of FTIR and 13C{1H} CP-MAS solid-state NMR techniques, whereas morphological characterization was provided by SEM microghaphy. The materials were proved to possess pH-dependent sequestration abilities, due to the presence of the weakly basic triazole linkers. Sequestration
  • . For instance, increased porosity of the CyNS obtained has been recently claimed by the use of a rigid terephthalonitrile unit as the linker [13]. On the other hand, it has been recently shown that polyamine linkers give rise to pH-sensitive materials with tunable adsorption abilities [12]. In order to
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Published 20 Jun 2018

Novel unit B cryptophycin analogues as payloads for targeted therapy

  • Eduard Figueras,
  • Adina Borbély,
  • Mohamed Ismail,
  • Marcel Frese and
  • Norbert Sewald

Beilstein J. Org. Chem. 2018, 14, 1281–1286, doi:10.3762/bjoc.14.109

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  • to investigate whether the high biological activity of the parent compound is retained and thus, construction of ADCs and PDCs would be feasible. This preparation could be done using traceless cleavable linkers that are sensitive to the distinct physiology of the tumour with enhanced level and
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Published 01 Jun 2018

An overview of recent advances in duplex DNA recognition by small molecules

  • Sayantan Bhaduri,
  • Nihar Ranjan and
  • Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

Graphical Abstract
  • and 10 with longer linkers exhibit relatively higher cytotoxicity in comparison to both distamycin and uramustine. The distamycin fragment directs binding to the A·T-rich sequences in the minor groove, and higher flexibility due to the longer linker allows optimal positioning of the mustard for DNA
  • , including quinolyl and benzoyl derivatives, and alkenes as linkers in order to investigate their antimicrobial properties [58][59]. One of these structural analogs, MGB-BP-3 (Figure 4), containing a stilbene like fragment as head group and two N-methylpyrroles attached to an aminoethylmorpholine as tail
  • –indole amide minor groove binders connected through alkyl or ethoxyethyl linkers were developed by Tecilla et al. [111]. The authors confirmed that these conjugates with tach units, either free or Zn(II)-complexed forms, bind strongly to the minor groove through electrostatic interactions with the
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Published 16 May 2018

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

  • Eirinaios I. Vrettos,
  • Gábor Mező and
  • Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

Graphical Abstract
  • as prodrugs, due to the covalent coupling of a peptide to a drug via specific linkers. The main building blocks of a simple PDC include a cytotoxic agent (drug), a tumor-homing peptide (navigating/targeting moiety) and a linker between them (Figure 2B). This class of prodrugs is continuously gaining
  • not to perturb the binding affinity of the peptide to its receptor and the drug efficacy. An inappropriate linker may impede the release of the drug from the PDC and therefore diminish its overall therapeutic potency. Linkers utilized in PDCs exist in different categories and vary on their length
  • , stability, release mechanism, functional groups, hydrophilicity/hydrophobicity etc. This linker can be designed to bear an enzyme-hydrolyzable unit (EHU) like a carboxylic ester or an amide bond, cleaved by esterases and amidases, respectively. The most commonly utilized linkers that bear a carboxylic ester
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Published 26 Apr 2018

Mannich base-connected syntheses mediated by ortho-quinone methides

  • Petra Barta,
  • Ferenc Fülöp and
  • István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

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  • ). Rokita et al. focused on generating o-QMs and used them as cross-linking and DNA alkylating agents. Starting from Mannich base 56 and transforming it by a number of synthetic steps, they were managed to elaborate a process that provides easy access to o-QM precursors containing a broad array of linkers
  • aminonaphthols and cyclic amines. Brønsted acid-catalysed reaction between aza-o-QMs and 2- or 3-substituted indoles. Formation of 3-(α,α-diarylmethyl)indoles 52 in different synthetic pathways. Alkylation of o-QMs with N-, O- or S-nucleophiles. Formation of DNA linkers and o-QM mediated polymers. Comparison of
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Published 06 Mar 2018

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

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  • synthesis, so they designed second generation inhibitors by changing the synthetically challenging α-Neu5Ac with alpha-hydroxy acids 2 [33][34]. Using a combinatorial approach, a library of non-hydrolyzable, non O-glycosidic third generation inhibitors were synthesised using appropriate linkers. The CTB
  • chelating mechanism. Hughes and co-workers synthesised and evaluated bivalent 1,2,3 triazole-linked galactopyranosides 14 and 15 as shown in Figure 7 [48]. They used a piperazine core as central divalent core on to which the galactose units were attached via flexible linkers. They found that these compounds
  • Bundle and co-workers were also working on analogous designs for shiga-like toxin [59]). They synthesised the inhibitors on a pentacyclene core on which galactose and m-nitrophenyl-α-D-galactopyranoside were attached by long flexible linkers (Figure 10) [60][61]. They found million-fold increases in
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Published 21 Feb 2018

Stimuli-responsive oligonucleotides in prodrug-based approaches for gene silencing

  • Françoise Debart,
  • Christelle Dupouy and
  • Jean-Jacques Vasseur

Beilstein J. Org. Chem. 2018, 14, 436–469, doi:10.3762/bjoc.14.32

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Published 19 Feb 2018

Synthesis and biological evaluation of RGD and isoDGR peptidomimetic-α-amanitin conjugates for tumor-targeting

  • Lizeth Bodero,
  • Paula López Rivas,
  • Barbara Korsak,
  • Torsten Hechler,
  • Andreas Pahl,
  • Christoph Müller,
  • Daniela Arosio,
  • Luca Pignataro,
  • Cesare Gennari and
  • Umberto Piarulli

Beilstein J. Org. Chem. 2018, 14, 407–415, doi:10.3762/bjoc.14.29

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  • synthesized by joining integrin ligands to α-amanitin via various linkers and spacers. The conjugates were evaluated for their ability to inhibit biotinylated vitronectin binding to the purified αVβ3 receptor, retaining good binding affinity, in the same nanomolar range as the free ligands. The
  • and co-workers conjugated α-amanitin to pHLIP (pH low insertion peptide) via linkers of different hydrophobicities [7]. The results indicated that pHLIP could deliver α-amanitin into cells and induce cell death in 48 h by a pH-mediated direct translocation across the membrane and cleavage of the
  • conjugates, the integrin ligands are bound to α-amanitin via a 6’-ether with two different linkers: an “uncleavable” six carbon aliphatic chain (Figure 3, compounds 7 and 8) and a lysosomally cleavable Val-Ala linker bound to a self-immolative spacer (Figure 3, compounds 9, 10 and 11). Integrin receptor
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Published 14 Feb 2018

Preparation of trinucleotide phosphoramidites as synthons for the synthesis of gene libraries

  • Ruth Suchsland,
  • Bettina Appel and
  • Sabine Müller

Beilstein J. Org. Chem. 2018, 14, 397–406, doi:10.3762/bjoc.14.28

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  • . Instead, linkers that allow a release of the trimers by a non-nucleophilic and/or non-basic treatment are required. In terms of trimer synthesis only one report in the literature describes such a strategy: The start nucleoside was loaded onto controlled pore glass (CPG) via an oxalyl anchor (Figure 5A
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Published 13 Feb 2018

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

  • Thanh-Tuân Bui,
  • Fabrice Goubard,
  • Malika Ibrahim-Ouali,
  • Didier Gigmes and
  • Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

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  • distribution of the LUMO over the central pyrimidine acceptor core and the adjacent phenylene linkers small ΔEST were determined (0.16 and 0.15 eV for T29 and T30, respectively), indicative of reduced electronic correlations between frontier orbitals and accounting for their high performance. Indeed, EQEs of
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Published 30 Jan 2018

Fluorogenic PNA probes

  • Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

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  • , as well as the types of linkers, need to be fine-tuned in order to obtain optimal results. In this respect, the ability to site-specifically label anywhere in the PNA molecule using a pre-formed dye-labeled monomer or a functionalized monomer that allows post-synthetic labeling is important [84
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Published 29 Jan 2018

Synthesis and spectroscopic properties of β-meso directly linked porphyrin–corrole hybrid compounds

  • Baris Temelli and
  • Hilal Kalkan

Beilstein J. Org. Chem. 2018, 14, 187–193, doi:10.3762/bjoc.14.13

Graphical Abstract
  • applications [21][22][23]. In order to achieve rapid energy and electron transfer between macrocycles, the short distance between subunits keeps an important place. Therefore, two important factors affect the physical and electronic properties of porphyrin–corrole conjugates: (i) type of linkers and (ii
  • ) position of substitution (meso or β). So far, corrole macrocyles have been integrated into porphyrin conjugates via anthracene, biphenylene, xanthene, dibenzofuran [16][17][18][19][20], amide [21] and triazole [22][23] linkers. Despite the large number of studies on the synthesis of porphyrin–corrole
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Published 22 Jan 2018

Exploring mechanochemistry to turn organic bio-relevant molecules into metal-organic frameworks: a short review

  • Vânia André,
  • Sílvia Quaresma,
  • João Luís Ferreira da Silva and
  • M. Teresa Duarte

Beilstein J. Org. Chem. 2017, 13, 2416–2427, doi:10.3762/bjoc.13.239

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  • further biomedical/pharmaceutical applications [71], such as cancer therapy [81][82][83]. MOFs combine coordination and supramolecular chemistry. Coordination chemistry is present in the coordination of organic molecules (linkers) to metal ions or clusters (coordination centers), while supramolecular
  • chemistry relies on the formation of intermolecular interactions between linker molecules. This combination results in 1D, 2D or 3D porous frameworks. The pore size can be adjusted by varying the size of the linkers, a modification that can be associated to the change in functional groups in the organic
  • environmental reasons. These issues also led to the quest for biodegradable MOFs, the first being prepared in 2010 by Miller et al. [77]. Another family of MOFs, ZIFs (zeolitic imidazolate frameworks), that involves organic imidazoles as linkers, has been explored for medicinal purposes as a result of the
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Published 14 Nov 2017

Structure–property relationships and third-order nonlinearities in diketopyrrolopyrrole based D–π–A–π–D molecules

  • Jan Podlesný,
  • Lenka Dokládalová,
  • Oldřich Pytela,
  • Adam Urbanec,
  • Milan Klikar,
  • Numan Almonasy,
  • Tomáš Mikysek,
  • Jaroslav Jedryka,
  • Iwan V. Kityk and
  • Filip Bureš

Beilstein J. Org. Chem. 2017, 13, 2374–2384, doi:10.3762/bjoc.13.235

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  • to the first absorption bands. The positions of the emission maxima copy trends seen in the absorption spectra. Increasing the donating ability of the attached peripheral R1-substituents results in a slight bathochromic shift, whereas extension of the π-system by acetylene linkers has an opposite
  • in modular way prepared by Suzuki–Miyaura, Migita–Stille, and Sonogashira cross-coupling reactions. The chromophores differ in the π-system extension as well as in the peripheral substitution. The thermal stability of 1–5 is mostly affected by the presence of acetylene linkers, 1,4-phenylene and 2,5
  • -thienylene linkers, and ferrocene termini. From the electrochemical data we can conclude that variation of the peripheral donors influences mostly the HOMO, which dictates the HOMO–LUMO gap. Absorption spectra showed two bands localized around 600 nm, which position weakly depend on the peripheral
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Published 08 Nov 2017

Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines

  • Satoru Mori and
  • Norio Shibata

Beilstein J. Org. Chem. 2017, 13, 2273–2296, doi:10.3762/bjoc.13.224

Graphical Abstract
  • diacetylene linkers, via a butadiyne and via an aryldiacetylene moiety (Figure 2). Such binuclear phthalocyanines that are connected via a rigid acetylene linker synthesized by Glaser or Sonogashira reactions have attracted attention due to their interesting effects resulting from further expansion of
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Published 27 Oct 2017

Intramolecular glycosylation

  • Xiao G. Jia and
  • Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

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  • , equal amounts of α- and β-anomers were obtained. Also, when a glucosyl acceptor was employed, mainly the 1,2-cis-linked product was obtained. Valverde et al. also investigated succinoyl tethers [54], but their studies were mainly focusing on phthaloyl and non-symmetrical linkers described below. Among
  • other flexible linkers investigated are carbonate [57], as well as oxalic [57], malonic [53][57][58], and glutaric [59] dicarboxylic acids. However, like in the case of succinoyl linkers, higher flexibility led to more relaxed stereoselectivity. Further variations upon this method involved the
  • freedom and also to form smaller ring sizes [81]. Templated oligosaccharide synthesis Recently, Demchenko and co-workers introduced templated oligosaccharide synthesis, wherein bisphenol A (BPA) was used as the template and succinoyl, glutaryl or phthaloyl linkers were used to tether glycosyl donors and
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Published 29 Sep 2017

Sugar-based micro/mesoporous hypercross-linked polymers with in situ embedded silver nanoparticles for catalytic reduction

  • Qing Yin,
  • Qi Chen,
  • Li-Can Lu and
  • Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 1212–1221, doi:10.3762/bjoc.13.120

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  • -linkers [4], and self-polycondensation of small molecular monomers [5]. Since the Tan group proposed the new synthetic strategy that "knits" low functionality rigid aromatic compounds with formaldehyde dimethyl acetal (FDA) as an external cross-linking agent through a Friedel–Crafts reaction to synthesize
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Published 22 Jun 2017

Strategies in megasynthase engineering – fatty acid synthases (FAS) as model proteins

  • Manuel Fischer and
  • Martin Grininger

Beilstein J. Org. Chem. 2017, 13, 1204–1211, doi:10.3762/bjoc.13.119

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  • restricted by ACP linkers and the protein scaffold. As calculated from the reported specific activity of 2,500 mU/mg [24], S. cerevisiae FAS runs about 18 iterative cycles per second (per set of active sites). Given that each cycle requires six productive interactions between the ACP and the catalytic
  • the walls of the reaction chambers, while the ACP domains are held centrally in the chamber by two unstructured linkers of about 20 to 50 amino acid residues in length (40 and 25 amino acids in S. cerevisiae FAS). Interestingly, duplicated ACP domains have been observed in certain fungal FAS, and ACP
  • phosphopantetheinylated [24][32], is located at the tip of the fold opposite to the N- and C-terminal attachment sites. This structural organization likely preserves linkers from interfering in ACP:domain interactions, and, concomitantly, may support the loading of the covalent acyl moiety by steering the acyl tail into
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Published 21 Jun 2017

Glyco-gold nanoparticles: synthesis and applications

  • Federica Compostella,
  • Olimpia Pitirollo,
  • Alessandro Silvestri and
  • Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

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  • space glycans from the Au surface is another fundamental factor to take into consideration in GAuNP design. Generally, the majority of the spacers are thiol-linkers, exploiting the strong soft–soft interaction between gold and sulfur. The spacer has the crucial role to stabilize GAuNPs in the
  • spacer in the glycan–protein interaction [67]. The authors considered different types of spacer in terms of chemical structure, length and rigidity and demonstrated that longer linkers resulted as the best performing ones, giving a better access to the protein pocket. Furthermore, they showed that rigid
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Published 24 May 2017

Interactions between shape-persistent macromolecules as probed by AFM

  • Johanna Blass,
  • Jessica Brunke,
  • Franziska Emmerich,
  • Cédric Przybylski,
  • Vasil M. Garamus,
  • Artem Feoktystov,
  • Roland Bennewitz,
  • Gerhard Wenz and
  • Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

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  • and friction by applying external stimuli onto the responsive ditopic linkers [47][48][49]. In contrast to previous work our molecular toolkit, based on ditopic connector molecules, allows the independent determination of unspecific interactions between CD polymers at tip and planar surface as well as
  • chains and their maximum length. Interaction of a shape-persistent CD polymer with ditopic guests. Schematic representation of tip and surface modifications realized in this study (bottom). Blue lines symbolize the CD polymers, red circles the complexed ditopic linkers. Absorption spectra of monomer 7
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Published 18 May 2017

Synthesis of structurally diverse 3,4-dihydropyrimidin-2(1H)-ones via sequential Biginelli and Passerini reactions

  • Andreas C. Boukis,
  • Baptiste Monney and
  • Michael A. R. Meier

Beilstein J. Org. Chem. 2017, 13, 54–62, doi:10.3762/bjoc.13.7

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  • various DHMP acids with different bifunctional linkers. Aliphatic aldehydes did not react well under these conditions (even after longer reaction periods of up to six days) and product isolation was not straightforward. For the subsequent Passerini reactions, the DHMP acids were dissolved in a mixture of
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Published 09 Jan 2017

A versatile route to polythiophenes with functional pendant groups using alkyne chemistry

  • Xiao Huang,
  • Li Yang,
  • Rikard Emanuelsson,
  • Jonas Bergquist,
  • Maria Strømme,
  • Martin Sjödin and
  • Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 2682–2688, doi:10.3762/bjoc.12.265

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  • conditions leading to exomethylene-EDOT [19]. Therefore, the usage of basic nucleophiles is problematic. Moreover, these heteroatom-based linkers between the polymer backbone and the pendant group usually have limited tolerance to acidic or basic conditions promoting hydrolysis, and some of them are
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Published 09 Dec 2016

Elongated and substituted triazine-based tricarboxylic acid linkers for MOFs

  • Arne Klinkebiel,
  • Ole Beyer,
  • Barbara Malawko and
  • Ulrich Lüning

Beilstein J. Org. Chem. 2016, 12, 2267–2273, doi:10.3762/bjoc.12.219

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  • Arne Klinkebiel Ole Beyer Barbara Malawko Ulrich Luning Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, D-24098 Kiel, Germany 10.3762/bjoc.12.219 Abstract New triazine-based tricarboxylic acid linkers were prepared as elongated relatives of
  • substituted) with two equivalents of an unsubstituted nitrile. Triple Suzuki coupling of the cores 3 with suitable phenyl- and biphenylboronic acid derivatives provided elongated tricarboxylic acid linkers as carboxylic acids 17 and 20 or their esters 16 and 19. Reduction of the nitro group and cleavage of
  • the methoxy group gave the respective amino and hydroxy-substituted triazine linkers. Keywords: isoreticular; linker; MOF; Suzuki coupling; triazine; Introduction A typical building block for many metal–organic frameworks (MOFs) [1][2][3][4] carries two functional groups such as carboxylic acids or
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Published 27 Oct 2016

DNA functionalization by dynamic chemistry

  • Zeynep Kanlidere,
  • Oleg Jochim,
  • Marta Cal and
  • Ulf Diederichsen

Beilstein J. Org. Chem. 2016, 12, 2136–2144, doi:10.3762/bjoc.12.203

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  • generate libraries of molecules from simpler building blocks by reversible reactions under thermodynamic control. Here we focus on the chemical modification of DNA oligonucleotides with acyclic diol linkers and demonstrate their potential for the deoxyribonucleic acid functionalization and generation of
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Published 06 Oct 2016

Application of Cu(I)-catalyzed azide–alkyne cycloaddition for the design and synthesis of sequence specific probes targeting double-stranded DNA

  • Svetlana V. Vasilyeva,
  • Vyacheslav V. Filichev and
  • Alexandre S. Boutorine

Beilstein J. Org. Chem. 2016, 12, 1348–1360, doi:10.3762/bjoc.12.128

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  • synthesis of conjugates of pyrrole–imidazole polyamide minor groove binders (MGB) with fluorophores and with triplex-forming oligonucleotides (TFOs). Diverse bifunctional linkers were synthesized and used for the insertion of terminal azides or alkynes into TFOs and MGBs. The formation of stable triple
  • part of the present article, we describe the synthesis of various linkers bearing different functional groups for simple and accessible introduction of azide and alkyne groups into biopolymers, fluorophores and ligands. Then, these linkers were introduced into the structure of MGBs and TFOs and used
  • for the synthesis of MGB-fluorophore and MGB-TFO conjugates via CuAAC (Figure 2). Properties of the conjugates obtained are discussed. Results and Discussion Synthesis of bifunctional linkers Two components in MGB-TFO conjugates must be connected by a linker, which is at least 12 chemical bonds long
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Published 30 Jun 2016
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