42397-72-8Relevant academic research and scientific papers
Crystal and Molecular Structure of the Complex between sym-Dibenzo-14-crown-4-oxyacetate and Li+, -*Li+*7.5H2O
Shoham, G.,Christianson, D. W.,Bartsch, R. A.,Heo, G. S.,Olsher, U.,Lipscomb, W. N.
, p. 1280 - 1285 (1984)
The synthesis and crystal structure of the title compound are described.Single crystal X-ray diffractometry indicates 8 formula units in the unit cell of parameters a = 20.779 Angstroem, b = 17.845 Angstroem, c = 13.903 Angstroem, β = 98.19o.Th
MULTI-WALLED CARBON NANOTUBES-SUPPORTED CROWN ETHERS, METHOD FOR PREPARING THEREOF AND USES THEREOF
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Paragraph 0036; 0037, (2017/05/05)
The present invention relates to multi-walled carbon nanotube-supported crown ether, a method for preparing the same, and uses thereof. More specifically, the crown ether is able to remarkably improve lithium adsorption function by being fixed to a multi-walled carbon nanotube support. In a certain embodiment, the preparation method can be performed by fixing hydroxy-dibenzo-14-crown-4 ether to multi-walled carbon nanotubes. The crown ether prepared by the method can be used for recovering useful metal ions (lithium ions). To this end, the method for preparing the multi-walled carbon nanotube-supported crown ether comprises the following steps: dispersing multi-walled carbon nanotubes in an acidic solution and ultrasonically treating the same to oxidize the multi-walled carbon nanotubes (step a); epoxidizing the oxidized multi-walled carbon nanotubes (step b); and functionalizing the epoxidized multi-walled carbon nanotubes by using the crown ether (step c).COPYRIGHT KIPO 2016
Microwave-assisted synthesis of dibenzo-crown ethers
Torrejos, Rey Eliseo C.,Nisola, Grace M.,Beltran, Arnel B.,Park, Myoung Jun,Patil, Basavaraj R.,Lee, Seong-Poong,Seo, Jeong Gil,Chung, Wook-Jin
, p. 109 - 115 (2014/03/21)
Microwave-assisted organic synthesis (MAOS) for dibenzo-substituted crown ethers is presented. Two routes were developed: (1) one-pot MAOS for symmetric dibenzo-crown ethers (DBC) and (2) a two-step MAOS via diphenol intermediates for both symmetric and asymmetric DBCs. MAOS were carried out in open or closed vessels, with or without temperature control at various microwave settings using different bases and reactants. Open vessel MAOS was limited by the volatility of reactants hence was less preferred than the closed vessel MAOS. DBC formation was highly affected by the cation size of the base, which acted as a template ion during DBCs ring closure. Closed vessel MAOS without temperature control was found most appropriate for DBC synthesis. Symmetric DBCs were conveniently obtained via one-pot MAOS whereas asymmetric DBCs were obtained from two-step MAOS via diphenol intermediates. The method was found expedient as it afforded satisfactory yields at considerably shorter reaction time than those in conventional methods.
Polybenzocrown ethers: Synthesis by cesium-assisted cyclization and solid-state structures
Hanes, Robert E.,Ellingsworth, Edward C.,Griffin, Scott T.,Rogers, Robin D.,Bartsch, Richard A.
, p. 217 - 237,21 (2020/08/24)
A series of large-ring polybenzocrown ethers is prepared by cesium-assisted cyclizations. Reactions of diphenols/bisphenols, dimesylates of oligoethylene glycols and cesium carbonate in MeCN produce the large-ring polybenzocrown ethers in high yields. To gain further insight into the structures of these compounds, solid-state structures of three large-ring crown ethers are obtained by X-ray diffraction.
The Stereochemistry of Crown Ethers II -- 1H and 13C NMR Structural Study in Solution
Kleinpeter, E.,Gaebler, M.,Schroth, W.,Mattinen, J.,Pihlaja, K.
, p. 387 - 391 (2007/10/02)
The 1H and 13C NMR spectra of a series of structurally related crown ethers have been recorded, and the signals assigned by means of 1H/13C heteronuclear correlated and 1H/1H homonuclear NOE difference spectroscopy.The NMR parameters so extracted have been used to discuss the preferred, rapidly interconverting solution conformations of the studied species.The high-field shifts in the 13C NMR spectra, within the so-called γ-fragments, and also the 1H/1H homonuclear NOEs, are particularly informative in this respect.The T1 relaxation times of the 13C atoms show segmental motions within the ether segments and suggest different intramolecular flexibilities for the studied compounds.KEY WORDS 1H/13C NMR 2D and 1D NOE difference spectroscopy Crown ethers Conformations in solution Intramolecular flexibility.
β1-Selective Adrenoceptor Antagonists. 1. Synthesis and β-Adrenergic Blocking Activity of a Series of Binary (Aryloxy)propanolamines
Kierstead, R. W.,Faraone, A.,Mennona, F.,Mullin, J.,Guthrie, R. W.,et al.
, p. 1561 - 1569 (2007/10/02)
A series of binary (aryloxy)propanolamines has been prepared and examined in vitro and in vivo for β-adrenoreceptor blocking activity.These symmetrical compounds consist of two (S)-(phenyloxy)propanolamine pharmacophores coupled through alkylenedioxy or poly(oxyethylenedioxy) linking units of varying lengths.Examples of such binary compounds linked through the 2,2', 3,3', and 4,4' positions in the aromatic rings of the pharmacophores have been prepared.In vitro and in vivo test data indicate that the 2,2' compounds tend to be selective β2-adrenergic blocking agents, the 4,4' binaries tend to be selective β1-blocking agents, and those compounds with 3,3' linkages exhibit intermediate selectivities.One of the 4,4'-linked binary compounds, 4s, exhibited potent, cardioselective β-blockade in vivo, which was of short duration and was accompanied by a prolonged tachycardia.
Synthesis of Highly Lipophilic Crown Ether Carboxylic Acids
Bartsch, Richard A.,Liu, Yung,Kang, Sang Ihn,Son, Byungki,Heo, Gwi Suk,et al.
, p. 4864 - 4869 (2007/10/02)
Synthetic routes to eight highly lipophilic crown ether carboxylic acids are described.Structural variations within this series of crown ether carboxylic acids include changes in the crown ether cavity size, the lipophilic group attachment site, and the b
Linewidth Alternation in the Electron Spin Resonance Spectrum of the Fluorene Radical Anion in the Presence of Dibenzo Crown Ethers
Rothwell, E. John,Tabner, Brian J.
, p. 1384 - 1391 (2007/10/02)
Two dibenzo crown ethers have been found to decompose slowly when in contact with alkali metals in tetrahydrofuran.Decomposition of these dibenzo crown ethers also occurs when they are brought into contact with a solution of the fluorene radical anion.The addition of the crown ethers to a solution of the radical anion has a dramatic effect upon the e.s.r. spectrum.This effect has been interpreted in terms of linewidth alternation.An intramolecular migration of the crown ether-alkali metal cation complex from one side of the radical anion plane to the other is proposed.It has been possible to examine the slow exchange region of the spectrum in the Li(1+)-dibenzo-18-crown-6-fluorene radical anion system.A surprising observation is that these results indicate the complexation of Li(1+) by dibenzo-18-crown-6.
Macrocyclic polyether compounds
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, (2008/06/13)
Macrocyclic polyether "crown" compounds of the formula EQU1 WHEREIN T is a C2 -C3 alkylene, A is EQU2 R being H or C1 -C18 alkyl, R2 and R3 being independently C1 -C18 alkyl, C2 -C4 alkenyl, or C6 -C14 aryl; Q and Z are independently 1,2-arylene (or saturated derivatives thereof) or substituted 1,2-arylene (or saturated derivatives thereof); a is 0, 1, 2, or 3; b is an integer from 3 to 20; y is 1 or zero; x1, x2, x3, and x4 are integers independently selected to give a 15-60 atom ring. Such crown compounds are generally useful in the formation of complexes with ionic metal compounds, thus making it possible to use certain chemical reagents in media wherein they are normally insoluble.
