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Search for "crown ether" in Full Text gives 53 result(s) in Beilstein Journal of Organic Chemistry.

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

  • Hendrik V. Schröder and
  • Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

Graphical Abstract
  • lasso, a structural motif which was also recently found in nature for peptides with high antibacterial efficacy [71]. In 12, the TTF molecule is not implemented in the thread but in the wheel component. In the neutral state, strong hydrogen bonding between the crown ether wheel and the dialkylammonium
  • . Very recently, our group reported on a crown/ammonium rotaxane 17 in which a TTF unit is implemented in the crown-ether wheel (Figure 15) [82]. The rotaxane was synthesized by a catalyst-free nitrile oxide capping strategy in 67% yield. In the neutral state, the wheel is strongly bound to the ammonium
  • diimide (NDI) unit and a divalent crown-ether wheel with a central TTF unit (Figure 17) [86]. The cofacial donor–acceptor complex whose formation is indicated by a deep green color is forced to stay in a cofacial orientation by mechanical bonding, even when the complex is redox-switched. UV–vis
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Published 20 Aug 2018

A switchable [2]rotaxane with two active alkenyl groups

  • Xiu-Li Zheng,
  • Rong-Rong Tao,
  • Rui-Rui Gu,
  • Wen-Zhi Wang and
  • Da-Hui Qu

Beilstein J. Org. Chem. 2018, 14, 2074–2081, doi:10.3762/bjoc.14.181

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  • polymers. Keywords: alkenyl bond; functional crown ether; stimuli-responsiveness; switchable rotaxane; Introduction Along with the development of supramolecular chemistry, much attention has been paid to the design and synthesis of novel and complicated mechanical interlocked molecules (MIMs) [1][2][3][4
  • base makes the DB24C8 moiety slide to the amide station and the macrocycle could move back to the DBA recognition site when acid was added (Scheme 1). The synthesis routes of the target compound [2]rotaxane R1 are shown in Scheme 2. Compounds 1 [32], 2 [33], 6 [34], 7 [35] and functional crown ether 9
  • amide reaction between compound 6 and 6-azidohexan-1-amine in the presence of 2-chloro-4,6-dimethoxy-1,3,5-triazine and N-methylmorpholine. Finally, the classical and effective “Click” reaction was used to produce the target compound [2]rotaxane R1. The crown ether 9 and dibenzylammonium ion (R2NH2
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Published 08 Aug 2018

A pyridinium/anilinium [2]catenane that operates as an acid–base driven optical switch

  • Sarah J. Vella and
  • Stephen J. Loeb

Beilstein J. Org. Chem. 2018, 14, 1908–1916, doi:10.3762/bjoc.14.165

Graphical Abstract
  • DB24C8 ring resides solely at the bis(pyridinium)ethane site and changes to colorless when the crown ether is shuttling (i.e., circumrotating) back and forth between the two recognition sites thus optically signalling the onset of the shuttling dynamics. Keywords: catenane; mechanically interlocked
  • reported [2]rotaxane molecular switches containing a single dibenzo[24]crown ether DB24C8 wheel and two different recognition sites; benzylanilinium and 1,2-bis(pyridinium)ethane [16]. These shuttles operate as bistable switches driven by acid/base chemistry and can be optically sensed by either a change
  • in color (yellow/colorless) for [1FDB24C8]2+ or a fluorescence change (OFF/ON) for [1ADB24C8]2+; see Figure 1. In addition, we have also previously prepared a [3]catenane containing two dibenzo[24]crown ether DB24C8 rings interlocked onto a much larger macrocyclic ring containing two 1,2-bis
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Published 25 Jul 2018

Synthesis of diamido-bridged bis-pillar[5]arenes and tris-pillar[5]arenes for construction of unique [1]rotaxanes and bis-[1]rotaxanes

  • Ying Han,
  • Li-Ming Xu,
  • Cui-Yun Nie,
  • Shuo Jiang,
  • Jing Sun and
  • Chao-Guo Yan

Beilstein J. Org. Chem. 2018, 14, 1660–1667, doi:10.3762/bjoc.14.142

Graphical Abstract
  • axle to prevent dissociation of the subcomponents. In recent years, many effects have been devoted to the construction and functionalization of pseudo[1]rotaxanes and [1]rotaxanes [11][12][13][14][15][16][17][18][19][20]. For this purpose, the well-known macrocycles such as crown ether [21][22][23
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Published 04 Jul 2018

Synthesis and stability of strongly acidic benzamide derivatives

  • Frederik Diness,
  • Niels J. Bjerrum and
  • Mikael Begtrup

Beilstein J. Org. Chem. 2018, 14, 523–530, doi:10.3762/bjoc.14.38

Graphical Abstract
  • inhibitors (Figure 2) [15][16][17][18]. The reported derivatives all displayed activity, but only with similar or reduced potency compared to the corresponding benzoic acid derivatives. Application of deprotonated N-triflylbenzamide derivatives as counter anions in supramolecular crown ether compounds for
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Published 27 Feb 2018

From dipivaloylketene to tetraoxaadamantanes

  • Gert Kollenz and
  • Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

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  • need for acid catalysis. As in the case of the addition of arylamines, monodecarboxylation takes place, and in the presence of a strong acid, they are converted to the tetraoxaadamantanes 28 and 29 (65–93%) [35]. Several bisdioxine derivatives of aromatic di- and triamines as well as crown-ether
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Published 02 Jan 2018

Complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives

  • Leonid S. Kikot',
  • Catherine Yu. Kulygina,
  • Alexander Yu. Lyapunov,
  • Svetlana V. Shishkina,
  • Roman I. Zubatyuk,
  • Tatiana Yu. Bogaschenko and
  • Tatiana I. Kirichenko

Beilstein J. Org. Chem. 2017, 13, 2056–2067, doi:10.3762/bjoc.13.203

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  • , Kharkiv, Ukraine 10.3762/bjoc.13.203 Abstract The complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives has been studied both in solution and in the solid state. In this paper we studied the influence of the crown ether ring
  • groups of Gibson [11], Huang [12], Chiu [13], Balzani [14] and Loeb [15] have achieved great success in this field. However, flexible structures and the relatively similar nature of crown ether complexation may limit, to a certain extent, their further use. Therefore, the search for new receptors based
  • into bis(paraphenylene)-34-crown-10 leads to changes in the paraquat complex structure and an increase in its stability from 730 M−1 to 20000 M−1 in acetone-d6 [18]. Chen and co-workers obtained receptors with different combinations of triptycene, pentiptycene and crown ether fragments, and their
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Published 04 Oct 2017

Poly(ethylene glycol)s as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins

  • Andrea Mascitti,
  • Massimiliano Lupacchini,
  • Ruben Guerra,
  • Ilya Taydakov,
  • Lucia Tonucci,
  • Nicola d’Alessandro,
  • Frederic Lamaty,
  • Jean Martinez and
  • Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 19–25, doi:10.3762/bjoc.13.3

Graphical Abstract
  • reaction of the corresponding ureido derivative B-Leu was slowed down and the methyl ester moiety was partially hydrolysed. Indeed, the base activity was increased due to the presence of water in PEG as well as by the PEG crown-ether-like effect [1], chelating the potassium cations. It is worth noticing
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Published 04 Jan 2017

Potent triazine-based dehydrocondensing reagents substituted by an amido group

  • Munetaka Kunishima,
  • Daiki Kato,
  • Nobu Kimura,
  • Masanori Kitamura,
  • Kohei Yamada and
  • Kazuhito Hioki

Beilstein J. Org. Chem. 2016, 12, 1897–1903, doi:10.3762/bjoc.12.179

Graphical Abstract
  • ], a crown-ether-based cyclotransferase [8], membrane fusion of small unilamellar vesicles to form giant unilamellar vesicles [9], modular methods for the affinity labeling of targeting proteins [10][11][12], and reaction acceleration on micelle interfaces [13][14]. Thus, various types of molecular
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Published 24 Aug 2016

Bright molecules for sensing, computing and imaging: a tale of two once-troubled cities

  • A. Prasanna de Silva

Beilstein J. Org. Chem. 2015, 11, 2774–2784, doi:10.3762/bjoc.11.298

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  • amine [3][24][30], an amino acid [18][31], a crown ether [32] or a cryptand [33] and the spacer could be an oligomethylene chain [34] or nothing at all [35][36]. Since such diverse systems allow the addressing of various problems and since the design is usually straightforward, the PET sensor/switch
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Published 29 Dec 2015

Polythiophene and oligothiophene systems modified by TTF electroactive units for organic electronics

  • Alexander L. Kanibolotsky,
  • Neil J. Findlay and
  • Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1749–1766, doi:10.3762/bjoc.11.191

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  • significant effect on the integrity of the polymer. The crown ether TTF modified polymers 11c,d were tested for electrochemical recognition of Ba2+ ions. At [Ba2+] saturation concentration of 4 mM the shifts of the first CV peak for 11c and 11d films were +60 and +30 mV with a TTF electrode coverage of 1.4
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Published 28 Sep 2015

Star-shaped tetrathiafulvalene oligomers towards the construction of conducting supramolecular assembly

  • Masahiko Iyoda and
  • Masashi Hasegawa

Beilstein J. Org. Chem. 2015, 11, 1596–1613, doi:10.3762/bjoc.11.175

Graphical Abstract
  • ]. Reflecting its strong π-donor ability, 1 was oxidized spontaneously in solution to afford 1•+ under ambient conditions. Multifunctional TTF-crown ether-substituted phthalocyanine (Pc) 2a and its copper(II) complex 2b were reported by Amabilino, Rowan, Nolte, and co-workers in 2005 [40]. The giant molecule 2a
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Published 10 Sep 2015

Spiro annulation of cage polycycles via Grignard reaction and ring-closing metathesis as key steps

  • Sambasivarao Kotha,
  • Mohammad Saifuddin,
  • Rashid Ali and
  • Gaddamedi Sreevani

Beilstein J. Org. Chem. 2015, 11, 1367–1372, doi:10.3762/bjoc.11.147

Graphical Abstract
  • , snoutane (1) [5], pentaprismane (2) [10], dodecahedrane (3) [11][12][13][14][15][16][17][18][19], cage crown ether 4 [20], amantadine (5) and pushpakenediol (6) [21] along with the target molecule 7 are shown in Figure 1. Interestingly the amino group containing cage molecule amantadine (5) exhibits
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Published 05 Aug 2015

Selected synthetic strategies to cyclophanes

  • Sambasivarao Kotha,
  • Mukesh E. Shirbhate and
  • Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

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Published 29 Jul 2015

Discrete multiporphyrin pseudorotaxane assemblies from di- and tetravalent porphyrin building blocks

  • Mirko Lohse,
  • Larissa K. S. von Krbek,
  • Sebastian Radunz,
  • Suresh Moorthy,
  • Christoph A. Schalley and
  • Stefan Hecht

Beilstein J. Org. Chem. 2015, 11, 748–762, doi:10.3762/bjoc.11.85

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  • Universität Berlin, Takustraße 3, 14195 Berlin, Germany. Fax: +49(0)308385-5366; Tel: +49(0)308385-2639 10.3762/bjoc.11.85 Abstract Two pairs of divalent and tetravalent porphyrin building blocks carrying the complementary supramolecular crown ether/secondary ammonium ion binding motif have been synthesized
  • . The crown ether/secondary ammonium ion binding motif [34] is a powerful tool to create well-defined pseudorotaxane structures [35][36][37][38][39], which have also served as precursors in rotaxane syntheses [40][41][42] thus providing access to interlocked, mechanically bound molecules. Based on these
  • for artificial light-harvesting systems [67][68][69][70][71][72][73]. Here, we report the synthesis of two new porphyrin-based di- and tetravalent ammonium guest molecules A2 and A4 and their complementary porphyrin-based di- and tetravalent crown ether hosts C2 and C4 (Figure 1). The selection of
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Published 12 May 2015

The preparation of new functionalized [2.2]paracyclophane derivatives with N-containing functional groups

  • Henning Hopf,
  • Swaminathan Vijay Narayanan and
  • Peter G. Jones

Beilstein J. Org. Chem. 2015, 11, 437–445, doi:10.3762/bjoc.11.50

Graphical Abstract
  • crown ether more closely [29], we next tried to reduce its carbonyl groups to methylene units by lithium aluminum hydride (Scheme 3). Interestingly, the process (reduction in refluxing THF for 7 h) caused a complete destruction of the newly created heterocyclic ring and provided the aldehyde 22 together
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Published 07 Apr 2015

Molecular cleft or tweezer compounds derived from trioxabicyclo[3.3.1]nonadiene diisocyanate and diacid dichloride

  • Gert Kollenz,
  • Ralf Smounig,
  • Ferdinand Belaj,
  • David Kvaskoff and
  • Curt Wentrup

Beilstein J. Org. Chem. 2015, 11, 1–8, doi:10.3762/bjoc.11.1

Graphical Abstract
  • structures are reproduced very well by DFT calculations. Similar endo,endo conformations are calculated for the bisamide crown ether derivatives 7, where two proximate and nearly parallel crown ether units endow the molecules with a claw-like molecular cleft or tweezer structure as evidenced by an enhanced
  • , such as the bis-crown ether diamides 7 (Scheme 3), would possess similar structures with parallel substituents. Accordingly, we investigated the structures of compound 7a and 7b computationally. Again, there are several possible conformers of each compound, but the lowest-energy conformers shown in
  • Figure 8 and Figure 9 reveal the claw-like character of the dangling chains. This is particularly noteworthy in compound 7b, where a cavity between the two crown-ether moieties is apparent (Figure 9). This suggests that this molecule might be able to form strong complexes with suitable metal ions. Cation
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Published 02 Jan 2015

Efficient CO2 capture by tertiary amine-functionalized ionic liquids through Li+-stabilized zwitterionic adduct formation

  • Zhen-Zhen Yang and
  • Liang-Nian He

Beilstein J. Org. Chem. 2014, 10, 1959–1966, doi:10.3762/bjoc.10.204

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  • cations derived from chelation between neutral ligands and Li+ are shown in Figure 1. The geometry optimizations were carried out by performing DFT calculations. Four O atoms in PEG150Me chelate with Li+ in a quasi-crown ether manner. For neutral ligands with PEG chain (PEG150MeIm, PEG150MeNH2
  • , PEG150MeTMG and PEG150MeBu2N), all the O and N atoms coordinate with Li+ in a quasi-aza-crown ether fashion. OctIm, OctTMG, TMG, DBU and DBN generate complexes whereby Li+ is bound only to N atoms. In contrast, the coordination ability of the N atom in OctBu2N is not strong enough to form a homogeneous
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Published 21 Aug 2014

Synthesis of a sucrose dimer with enone tether; a study on its functionalization

  • Zbigniew Pakulski,
  • Norbert Gajda,
  • Magdalena Jawiczuk,
  • Jadwiga Frelek,
  • Piotr Cmoch and
  • Sławomir Jarosz

Beilstein J. Org. Chem. 2014, 10, 1246–1254, doi:10.3762/bjoc.10.124

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  • designed for such receptors, sugars are the most promising due to their availability and biocompatibility. Up to date only monosaccharides have found a wide application in the synthesis of crown ether analogs [5][6]. The disaccharide scaffold is much less pronounced [7]. During the past decade we have
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Published 28 May 2014

Molecular recognition of isomeric protonated amino acid esters monitored by ESI-mass spectrometry

  • Andrea Liesenfeld and
  • Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 825–831, doi:10.3762/bjoc.10.78

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  • trace amounts of material, and can be used to explore competitive experiments that are difficult to perform using UV–vis or NMR spectroscopy. Results and Discussion Design and synthesis of the concave templates Ammonium ions exhibit strong binding affinity towards crown ether moieties. Hence, we decided
  • scaffold that has been demonstrated to be a valuable part of some receptors [12][13], we decided to employ this motif. Therefore, we designed the two compounds 1 and 2 shown in Figure 2 that differ only in the bridging element between the crown ether group and the spirobifluorene. The synthesis of 1 and 2
  • target compounds 1 and 2 in moderate yields (Scheme 2). Molecular recognition studies With our crown ether derivatives 1 and 2 in hands we studied their recognition behaviour towards the L-leucine isomers. Usually, spectroscopic techniques like NMR or UV–vis spectroscopy are used for this purpose
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Published 09 Apr 2014

Direct and indirect single electron transfer (SET)-photochemical approaches for the preparation of novel phthalimide and naphthalimide-based lariat-type crown ethers

  • Dae Won Cho,
  • Patrick S. Mariano and
  • Ung Chan Yoon

Beilstein J. Org. Chem. 2014, 10, 514–527, doi:10.3762/bjoc.10.47

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  • provided a solid foundation for the design of new strategies for the preparation of interesting members of the crown ether family. Substances that possess polyheteroatom-containing macrocyclic rings were carefully investigated owing to their interesting chemical and biological properties. Prime examples of
  • binding properties with a variety of cationic guests. In typical cases, carbon or nitrogen-pivot lariat crown ethers are comprised of crown ether cores and one or more heteroatom-containing side arms that are covalently bonded to carbon or nitrogen in the core. The skeletal framework and position of
  • electron donor sites in these substances are ideally suited to capture cations in the form of chelate structures [70][71][72][73][74][75][76][77][78][79]. Several practical synthetic protocols have been developed to prepare members of the crown ether familiy. In most cases, the approaches utilize the
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Published 27 Feb 2014

Synthesis of the calcilytic ligand NPS 2143

  • Henrik Johansson,
  • Thomas Cailly,
  • Alex Rojas Bie Thomsen,
  • Hans Bräuner-Osborne and
  • Daniel Sejer Pedersen

Beilstein J. Org. Chem. 2013, 9, 1383–1387, doi:10.3762/bjoc.9.154

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  • ). Previously, 4 has been synthesised by nucleophilic aromatic substitution on commercially available aryl fluoride 13 using crown ether and potassium acetate in acetonitrile [14]. Unfortunately, we found it difficult to drive the reaction to completion using the published method, obtaining only low yields of
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Published 09 Jul 2013

Recent advances towards azobenzene-based light-driven real-time information-transmitting materials

  • Jaume García-Amorós and
  • Dolores Velasco

Beilstein J. Org. Chem. 2012, 8, 1003–1017, doi:10.3762/bjoc.8.113

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  • thermal cis-to-trans isomerisation process of azobenzenes 1–3 were all close to zero, as expected [44]. These values perfectly correlate with those found in the literature for the azobenzene-bridged crown-ether 3,3’-[1,10-diaza-4,7,13,16-tetraoxa-18-crown-6]-biscarbonylazobenzene, which thermally
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Published 04 Jul 2012

Fifty years of oxacalix[3]arenes: A review

  • Kevin Cottet,
  • Paula M. Marcos and
  • Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

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Published 07 Feb 2012

Effects of anion complexation on the photoreactivity of bisureido- and bisthioureido-substituted dibenzobarrelene derivatives

  • Heiko Ihmels and
  • Jia Luo

Beilstein J. Org. Chem. 2011, 7, 278–289, doi:10.3762/bjoc.7.37

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  • by the selective preorganization of the substrates by hydrogen bonding between neutral organic functionalities with an appropriate substitution pattern or by complexation of crown-ether units to cationic guest molecules [1][2][3]. In contrast, the selective anion recognition has not been employed
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Published 04 Mar 2011
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