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Search for "anions" in Full Text gives 383 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Chiral bisoxazoline ligands designed to stabilize bimetallic complexes

  • Deepankar Das,
  • Rudrajit Mal,
  • Nisha Mittal,
  • Zhengbo Zhu,
  • Thomas J. Emge and
  • Daniel Seidel

Beilstein J. Org. Chem. 2018, 14, 2002–2011, doi:10.3762/bjoc.14.175

Graphical Abstract
  • linkers. In addition, each amide moiety, upon deprotonation (a requirement for complex formation), would provide a formal negative charge on the ligand, thus resulting in increased complex stability while reducing the number of spectator anions associated with the two metals. Different combinations of
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Published 01 Aug 2018

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

  • Vladimir A. Burilov,
  • Guzaliya A. Fatikhova,
  • Mariya N. Dokuchaeva,
  • Ramil I. Nugmanov,
  • Diana A. Mironova,
  • Pavel V. Dorovatovskii,
  • Victor N. Khrustalev,
  • Svetlana E. Solovieva and
  • Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

Graphical Abstract
  • attention to the synthesis of host molecules with high affinity to biologically important anions [1][2][3][4][5]. Among these anions, nucleotide recognition and sensing represents an especially important research area due to the great biological significance of these anions. Adenine-containing nucleotides
  • nucleotides must possess selectivity towards these anions. From this point of view, nucleotide receptors based on polyammonium cations are of great demand because the electrostatic interactions of such polyammonium systems and negatively charged phosphates are strong. Hydrogen bonding [8] and π-stacking
  • highly explosive [29]. Usually azide groups are installed in the upper rim of the macrocycle by a chloromethylation reaction and subsequent nucleophilic substitution by azide anions [30][31] forming rather flexible azidomethyl fragments. In this investigation more rigid arylazide calixarene derivatives
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Published 31 Jul 2018

Synthesis of 9-arylalkynyl- and 9-aryl-substituted benzo[b]quinolizinium derivatives by Palladium-mediated cross-coupling reactions

  • Siva Sankar Murthy Bandaru,
  • Darinka Dzubiel,
  • Heiko Ihmels,
  • Mohebodin Karbasiyoun,
  • Mohamed M. A. Mahmoud and
  • Carola Schulzke

Beilstein J. Org. Chem. 2018, 14, 1871–1884, doi:10.3762/bjoc.14.161

Graphical Abstract
  • tuning of the stereoelectronic or steric properties of substituents. Structures of 9-substituted benzo[b]quinolizinium derivatives 1 and 2. Molecular structures of derivatives 2a (top) and 2b (bottom) in the solid state. Ellipsoids are shown at the 50% probability level. The counter anions and solvent
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Published 23 Jul 2018

Preparation and X-ray structure of 2-iodoxybenzenesulfonic acid (IBS) – a powerful hypervalent iodine(V) oxidant

  • Irina A. Mironova,
  • Pavel S. Postnikov,
  • Rosa Y. Yusubova,
  • Akira Yoshimura,
  • Thomas Wirth,
  • Viktor V. Zhdankin,
  • Victor N. Nemykin and
  • Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 1854–1858, doi:10.3762/bjoc.14.159

Graphical Abstract
  • selectively affords the respective iodine(V) product after heating at 60 °C for 16 h with almost quantitative conversion. The aqueous solution containing IBS-Na (as sodium salt) and inorganic products resulting from the reduction of NaIO4 was treated with silver nitrate to precipitate I– and IO3– anions. The
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Published 20 Jul 2018

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

  • Cristina Morar,
  • Pedro Lameiras,
  • Attila Bende,
  • Gabriel Katona,
  • Emese Gál and
  • Mircea Darabantu

Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145

Graphical Abstract
  • of the expected 8 H/P-1 unit. On the IR timescale (Figure 4a–d), the comparative spectra of compounds 7a/7b, 7b/trimesic acid, 8/C1 and 9/C3 fully proved the presence of only the tris-carboxylate anions [63][65][66]. (i) The spectrum of dendritic salt 7b was almost the duplicate of that of covalent
  • occurrence of a starburst effect. The “salt”-like nature of the G-2 dendrimers (obtained by a carboxyl/amino 1:3 stoichiometric trimerisation) could be unambiguously assigned by means of 1H NMR (in solution) and IR (solid state), confirming the existence of the only tris-carboxylate anions. TEM analysis
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Published 09 Jul 2018

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

  • Claudia Lar,
  • Adrian Woiczechowski-Pop,
  • Attila Bende,
  • Ioana Georgeta Grosu,
  • Natalia Miklášová,
  • Elena Bogdan,
  • Niculina Daniela Hădade,
  • Anamaria Terec and
  • Ion Grosu

Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115

Graphical Abstract
  • titration; 1,3,5-triazine; Introduction Cryptands with C3-symmetric aromatic reference groups are exciting targets, on the one hand due to the challenges encountered in their synthesis and on the other due to their ability (macrobicyclic effect [1]) to form supramolecular assemblies with cations, anions or
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Published 06 Jun 2018

Imide arylation with aryl(TMP)iodonium tosylates

  • Souradeep Basu,
  • Alexander H. Sandtorv and
  • David R. Stuart

Beilstein J. Org. Chem. 2018, 14, 1034–1038, doi:10.3762/bjoc.14.90

Graphical Abstract
  • approach to N-aryl imides is to employ aniline starting materials (Scheme 1b, left), as was done in the synthesis of pentoxazone and related herbicides [2]. The alternative aromatic substitution approach with imide anions (Scheme 1b, right) is hampered by their low nucleophilicity [3]. Therefore
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Published 11 May 2018

Electrochemically modified Corey–Fuchs reaction for the synthesis of arylalkynes. The case of 2-(2,2-dibromovinyl)naphthalene

  • Fabiana Pandolfi,
  • Isabella Chiarotto and
  • Marta Feroci

Beilstein J. Org. Chem. 2018, 14, 891–899, doi:10.3762/bjoc.14.76

Graphical Abstract
  • water to dihydrogen and hydroxide anions would be faster than the reduction of 1a. The overall reaction would be a one-electron process catalyzed by water reduction (Scheme 7) [32]. It is thus possible by selecting the electrolysis conditions to synthesize selectively 2-ethynylnaphthalene (2a, Table 1
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Published 23 Apr 2018

One-pot synthesis of diaryliodonium salts from arenes and aryl iodides with Oxone–sulfuric acid

  • Natalia Soldatova,
  • Pavel Postnikov,
  • Olga Kukurina,
  • Viktor V. Zhdankin,
  • Akira Yoshimura,
  • Thomas Wirth and
  • Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 849–855, doi:10.3762/bjoc.14.70

Graphical Abstract
  • improve the yields. Subsequently it was shown that the addition of aqueous potassium bromide can be modified and other counter anions can be introduced to prepare different diaryliodonium salts. This has been demonstrated in the preparation of diaryliodonium salts using 1-iodo-3-trifluoromethylbenzene (1b
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Published 12 Apr 2018

Phosphodiester models for cleavage of nucleic acids

  • Satu Mikkola,
  • Tuomas Lönnberg and
  • Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

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Published 10 Apr 2018

Synthesis of a sucrose-based macrocycle with unsymmetrical monosaccharides "arms"

  • Karolina Tiara,
  • Mykhaylo A. Potopnyk and
  • Sławomir Jarosz

Beilstein J. Org. Chem. 2018, 14, 634–641, doi:10.3762/bjoc.14.50

Graphical Abstract
  • ; Introduction Chiral macrocyclic compounds play an important role in supramolecular and biological systems [1][2]. Many of them serve as convenient receptors for cations [3], anions [4], ion pairs [5], neutral molecules [6] etc. Binaphthols [7][8][9], amino acids [10], chiral diamines [11][12], carbohydrates
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Published 15 Mar 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

Progress in copper-catalyzed trifluoromethylation

  • Guan-bao Li,
  • Chao Zhang,
  • Chun Song and
  • Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

Graphical Abstract
  • found that the generation rate of trifluoromethyl anions is much higher than the second step affording B and CuI. Thus, there is no sufficient recirculated CuI to react with trifluoromethyl before its decomposition. Optimizations were then performed to overcome this shortcoming in 2009 [12], a series of
  • readily available TMSCF3 (Scheme 2). Similarly, the recycling of CuI was inefficient and led to the degradation of excessive trifluoromethyl anions. Differently, a novel strategy was developed to solve this problem, a Lewis acid such as trialkyl borate was added for the temporary trapping of the in situ
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Published 17 Jan 2018

Photocatalytic formation of carbon–sulfur bonds

  • Alexander Wimmer and
  • Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

Graphical Abstract
  • , thiobenzanilides were first deprotonated to the respective sulfur anions. Photoexcited [Ru(bpy)3]2+* reacts with dioxygen to [Ru(bpy)3]3+. Subsequent single-electron oxidation of the anion closes the catalytic cycle and generates a thiyl radical, which performs a cycloaddition to the aromatic anilide moiety
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Published 05 Jan 2018

Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays

  • Marco Russo,
  • Daniele La Corte,
  • Annalisa Pisciotta,
  • Serena Riela,
  • Rosa Alduina and
  • Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2751–2763, doi:10.3762/bjoc.13.271

Graphical Abstract
  • observed that K values for the neutral guest 1 and the anionic guest 3 regularly decrease on decreasing the pH, i.e., on increasing the average charge on the host, whereas the opposite is observed with anions 2 and 4. In all cases, however, a regular increase of RΘ values generally occurs, with few
  • guests 2 and 4 the same effects are largely counterbalanced by the concomitant occurrence of very favourable Coulomb interactions. However, the case of guest 3 is intriguing, because its trend of K values neatly mismatches those for the other anions. This surprising finding can be explained considering
  • the grounds of these results, the behaviour of CD2 and CD3 was investigated with anions 2 and 4 only. The results obtained appear quite peculiar. In fact, monoanion 2 does not present the same simple monotonic trend for K observed with CD1; by contrast, for dianion 4 the expected regular increase of K
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Published 18 Dec 2017

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

  • Anna Kuźnik,
  • Roman Mazurkiewicz and
  • Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

Graphical Abstract
  • reported by Fuchs, who obtained 1,3-cyclohexadienes 54 by reaction of 1,3-butadienyltriphenylphosphonium bromide with enolate anions 53 derived from aldehydes or ketones in yields of 35–57% (Scheme 36). The nucleophilic attack here was directed at position 4 of the diene [11]. Hewson and MacPherson
  • of cyclic alkenes in the intramolecular Wittig reaction from vinylphosphonium bromide and ketoesters as precursors of carbon nucleophiles. Synthesis of 1,3-cyclohexadienes by reaction of 1,3-butadienyltriphenylphosphonium bromide with enolate anions. Synthesis of bicyclo[3.3.0]octenes by reaction of
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Published 15 Dec 2017

Binding abilities of a chiral calix[4]resorcinarene: a polarimetric investigation on a complex case of study

  • Marco Russo and
  • Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2698–2709, doi:10.3762/bjoc.13.268

Graphical Abstract
  • amount of base cannot result in the exclusive formation of the desired anionic form alone, but rather in a mixture of differently charged anions at equilibrium. Of course, the average charge of the anionic species formed equals the number of base equivalents added. Moreover, it can be algebraically shown
  • within a couple of days, even if stored at low temperature (4 °C). Therefore, the proline subunits easily undergo racemization under alkaline conditions. Binding properties of CAP Based on the previous results, we preliminarily tested the interaction of guests 1–12 with CAP−2. We observed that anions 1
  • and 2 and aliphatic cations 3 and 4 do not appreciably interact with the host. Lack of binding with the anions can be easily attributed to the occurrence of unfavourable Coulomb repulsion. On the other hand, the fact that even cations 3 and 4 do not show appreciable affinity for the host clearly
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Published 15 Dec 2017

A Brønsted base-promoted diastereoselective dimerization of azlactones

  • Danielle L. J. Pinheiro,
  • Gabriel M. F. Batista,
  • Pedro P. de Castro,
  • Leonã S. Flores,
  • Gustavo F. S. Andrade and
  • Giovanni W. Amarante

Beilstein J. Org. Chem. 2017, 13, 2663–2670, doi:10.3762/bjoc.13.264

Graphical Abstract
  • and Mannich acceptors [20][21][22][23]. Enolate anions derived from azlactone are effective intermediates for the functionalization of α-amino acids. However, the acylation of the enolate ion by another azlactone has been less reported in the literature [24][25][26]. This transformation affords an
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Published 13 Dec 2017

Structural diversity in the host–guest complexes of the antifolate pemetrexed with native cyclodextrins: gas phase, solution and solid state studies

  • Magdalena Ceborska,
  • Magdalena Zimnicka,
  • Aneta Aniela Kowalska,
  • Kajetan Dąbrowa and
  • Barbara Repeć

Beilstein J. Org. Chem. 2017, 13, 2252–2263, doi:10.3762/bjoc.13.222

Graphical Abstract
  • suggests that the PTX molecule is loosely attached to the surface of two (or more) closely bonded CDs, thus forming weakly bound exclusion-type associates. All 1:1 CDs/PTX complexes follow the same dissociation pathway, i.e., they separate into singly charged anions of PTX and CD (the CID spectra are
  • pump at a flow rate of 10 µL/min. The ion source parameters were optimized to obtain the highest possible abundance of the complex anions and were adjusted as follows: ion-spray voltage (IS) −3.5 kV, declustering potential (DP) −15 V, entrance potential (EP) −10 V. In CID experiments, nitrogen was used
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Published 25 Oct 2017

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

  • Yaroslav D. Boyko,
  • Valentin S. Dorokhov,
  • Alexey Yu. Sukhorukov and
  • Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

Graphical Abstract
  • the first two routes. Tanimoto et al. [22] recently suggested N-siloxysulfonamides 4 as stable sources of unsaturated nitroso compounds (Scheme 1, reaction (4)). However, this approach was used only for the generation of nitrosoallenes so far. Addition of C–H acids anions to conjugated nitrosoalkenes
  • Stabilized enolates and their equivalents are the most studied C-nucleophiles in Michael addition reactions with nitrosoalkenes. A first systematic study in this area was done by Ohno and co-authors [13][23], who reported the addition of diethyl malonate and acetylacetone anions to cyclic nitrosoalkenes
  • (silyloxy)enamines 3 under these conditions. Nitronate anions also react as C-nucleophiles with N,N-bis(silyloxy)enamines 3 producing β-nitrooximes 7 in good yields (Scheme 4) [20][25]. Efficient coupling of DBU-nitronate salts derived from primary nitro compounds with enamines 3 was achieved at –78 °C upon
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Published 23 Oct 2017

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

Graphical Abstract
  • (Figure 7). Within the row molecules are arranged by π–π stacking interactions between the side aromatic fragments of the clips with a centroid–centroid distance in the range of 3.51–3.71 Å. There are acetonitrile solvate molecules and hexafluorophosphate anions between neighboring rows. Quantum chemical
  • for the complexes (lgK) of molecular clips 1–5 with guests 7–10 on the size of crown ether cycles in acetonitrile at 20 °C. Molecular structures of complexes of clips 3, 2 and 5 with paraquat (7). Anions and solvate molecules are omitted for clarity. Crystal packing of molecules in complexes of clips
  • 2, 3 and 5 with paraquat (7). Anions and solvate molecules are omitted for clarity. Molecular structures of complexes 2@8 and 3@8. The hydrogen bonds are shown by blue lines. Anions and solvate molecules are omitted for clarity. Molecular structures of complexes 2@9 and 3@9. The hydrogen bonds are
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Published 04 Oct 2017

p-tert-Butylthiacalix[4]arenes functionalized by N-(4’-nitrophenyl)acetamide and N,N-diethylacetamide fragments: synthesis and binding of anionic guests

  • Alena A. Vavilova and
  • Ivan I. Stoikov

Beilstein J. Org. Chem. 2017, 13, 1940–1949, doi:10.3762/bjoc.13.188

Graphical Abstract
  • -diethylacetamide groups in cone and partial cone conformations have been synthesized. Their complexation ability towards a number of tetrabutylammonium salts n-Bu4NX (X = F−, Cl−, Br−, I−, CH3CO2−, H2PO4−, NO3−) was studied by UV spectroscopy. The effective receptor for the anions studied as well as selective
  • receptors for F−, CH3CO2− and H2PO4− ions, which based on the synthesized thiacalix[4]arenes, have been obtained. It was shown that p-tert-butylthiacalix[4]arene tetrasubstituted at the lower rim by N-(4’-nitrophenyl)acetamide moieties bonded to the anions studied with association constants within the range
  • of 3.55 × 103–7.94 × 105 M−1. Besides, the binding selectivity for F−, Cl−, CH3CO2−, and H2PO4− anions against other anions was in the range of 4.1–223.9. Substituting one or two fragments in the macrocycle with N,N-diethylacetamide groups significantly reduces the complexation ability of the
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Published 13 Sep 2017

Enzymatic synthesis of glycosides: from natural O- and N-glycosides to rare C- and S-glycosides

  • Jihen Ati,
  • Pierre Lafite and
  • Richard Daniellou

Beilstein J. Org. Chem. 2017, 13, 1857–1865, doi:10.3762/bjoc.13.180

Graphical Abstract
  • directed mutagenesis of the potent residues [64]. In these cases, the mutated enzymes are no longer able to perform the hydrolysis of the substrates. The use of external and suitable nucleophilic anions such as azide, formate or acetate allows the rescue of the activity and can also represent an efficient
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Published 05 Sep 2017

Mechanochemical synthesis of thioureas, ureas and guanidines

  • Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

Graphical Abstract
  • research, Friščić et al. introduced the so called "ion and liquid-assisted grinding" or ILAG by recognizing the effect of cations such as Na+, K+ or NH4+ or anions like Cl−, NO3− and SO42− on the formation of polymorphs during LAG synthesis of metal-organic frameworks [21]. Recently, Jones et al. employed
  • -tolylurea (33) reported by Swinburne and Steed in 2009 [45]. This compound was found to bind anions individually and as part of a tripodal anion receptor. In contrast to solution synthesis in dichloromethane for 12 hours, the mechanochemical solvent-free coupling of 3-aminopyridine and 4-methylphenyl
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Published 01 Sep 2017

Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C–S cross-coupling reaction

  • Debasish Sengupta,
  • Koushik Bhowmik,
  • Goutam De and
  • Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 1796–1806, doi:10.3762/bjoc.13.174

Graphical Abstract
  • around 4 nm, which is corroborated from the X-ray line broadening method on the <100> peak of Ni(OH)2 in Figure 3b. It is likely that Ni(OH)2 could form during the recovery of the catalyst. In the recycle run, the major catalytic constituent Ni(OH)2 is presumably reduced by thiolate anions to Ni(I
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Published 28 Aug 2017
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