• Title/Summary/Keyword: Arenes

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Synthesis and Structure Identification of ABCH Type Calix[4]arenes: Two Step Synthesis of Asymmetrically Substituted Calix[4]arenes from Monoalkylcalix[4]arenes

  • 남계천;김종민;박영자
    • Bulletin of the Korean Chemical Society
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    • v.19 no.7
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    • pp.770-776
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    • 1998
  • Several ABCH type chiral calix[4]arenes were prepared from monoalkyl calix[4]arenes by treating with various acyl halide, followed by reacting with benzoyl chloride in pyridine. These asymmetrically substituted ABCH type calix[4]arenes are obtained as racemates mixture which are confirmed by the chiral shift reagent in 1H NMR spectra. The molecular and crystal structure of 5-nitro-26-allyloxy-25-benzoyloxy-28-isobutyryloxy-27-hydroxycalix[4]arene 8a has been determined by the X-ray diffraction method. Two independent enantiomeric molecules are crystallized in a 1: 1 racemate mixture. They are in the partial cone conformation in which the benzoyloxy phenyl group is down. There is a bifurcated intramolecular hydrogen bonding involving three functional groups in each molecule.

Synthesis of Calix[4]arenes in AAAB or AABB Type Substitution at Upper Rim

  • 노광현;권경미;김종은
    • Bulletin of the Korean Chemical Society
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    • v.17 no.6
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    • pp.525-528
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    • 1996
  • Seven cali[4]arenes, having two different substituents in AAAB or AABB pattern at the upper rim of calix were synthesized by fragmentation condensation reaction of p-substituted phenol trimer (AAA) with 2,6-bishydroxymethylated 4-substituted phenol (B) or that of dimer (AA) with 2,2'-bishydroxymethylated dimer (BB). An equimolar mixture of the coupling components (trimer and monomer or dimer and dimer) was refluxed in dioxane in the presence of TiCl4to afford calix[4]arene 6 and 7 in 15-38% yield. The structure of calix[4]arenes was confirmed by elemental analysis and the 1H/13C NMR spectroscopy.

Theoretical Study on the Conformations of Homooxacalix[4]arenes

  • Ham, Si-Hyun
    • Bulletin of the Korean Chemical Society
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    • v.25 no.12
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    • pp.1911-1916
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    • 2004
  • The conformational preference of tetrahomodioxacalix[4]arenes with three different para substituents on the phenolic ring has been investigated by using ab initio molecular orbital theory (RHF/6-31$G^{\ast}$) and density functional theory (B3LYP/6-31$G^{\ast}$). The stability order is predicted to be cone > C-1,2-alternate > partial cone > 1,3-alternate > COC-1,2-alternate. The distorted cone conformation is found to be most stable in a gas phase and the calculated results are in agreement with the reported $^1$H NMR and X-ray experimental observations. The substitution of methylene with dimethyleneoxa bridges increases the size of the annulus of the molecule, its conformational mobility, and the number of hydrogen bonding patterns. The thermodynamic stability and the conformational characteristics of tetrahomodioxacalix[4]arenes are discussed in regards of the number of phenolic hydrogen bonding patterns and the polarity of a molecule. The substituent effects on the para position of the phenolic ring are also introduced.

Synthesis of Several Diester Group-Containing Calix[4]arenes

  • 남계준;양용식;전종철;최용국
    • Bulletin of the Korean Chemical Society
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    • v.17 no.6
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    • pp.502-506
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    • 1996
  • Several ester group-containing calix[4]arenes were synthesized by the reaction of calix[4]arene and various acyl chlorides. Two or four ethyl succinyl units could be introduced into the calix[4]arene lower rim depending on the reaction conditions. But the mixture of three and four ethyl malonyl substituted calix[4]arenes were obtained and only three ethyl oxalyl units were introduced at the lower rim of calix[4]arene. Interestingly when calix[4]arene was treated with ethyl oxalyl chloride in the presence of aluminum chloride, two ethyl oxalyl units were introduced at the upper rim of calix[4]arene. The conformation of those ester-containing calix[4]arenes was presented based on the 1H and 13C NMR spectra.

Selective Acyl and Alkylation of Monobenzoyl p-tert- Buty1calix[4]arene

  • 김종민;전종철;남계춘
    • Bulletin of the Korean Chemical Society
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    • v.18 no.4
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    • pp.409-415
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    • 1997
  • Several calixarene derivatives of 5,11,17,23-tetra-tert-butyl-25-(3,5-dinitrobenzoyloxy)-26,27,28-trihydroxycalix[4]arene 2 were synthesized by the reaction of 2 with several acyl and alkylating agents in the presence of base such as pyridine and K2CO3 in THF. Acylation of monobenzoylated p-tert-butylcalix[4]arene 2 yielded their corresponding 1,3-diacylated calix[4]arenes 3a-3g. On the other hand, alkylation of 2 produced a variety calix[4]arene derivatives such as 1,2- and 1,3-disubstituted calix[4]arenes 4a-4c, 4e-4f, or 1,2,4-trisubstituted calix[4]arene 4d. 1,2-Disubstituted calix[4]arenes are chiral. All derivatives exist as a cone conformation based on NMR studies.

Polymeric Membrane Cesium-Selective Electrodes Based on Quadruply-bridged Calix[6]arenes

  • Choe, Eun Mi;O, Hye Jin;Go, Seung Hwa;Choe, Yong Guk;Nam, Gye Chun;Jeon, Seung Won
    • Bulletin of the Korean Chemical Society
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    • v.22 no.12
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    • pp.1345-1349
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    • 2001
  • New quadruply-bridged calix[6]arenes (I-V) have been studied as cesium selective ionophores in poly(vinyl chloride) (PVC) membrane electrodes. PVC membranes were prepared with dioctyl sebacate (DOS) or 2-nitrophenyl octyl ether (o-NPOE) as the sol vent mediator and potassium tetrakis(p-chlorophenyl)borate as the lipophilic salt additive. These ionophores produced electrodes with near-Nernstian slope. The selectivity coefficients for cesium ion with respect to alkali, alkaline earth and ammonium ions have been determined. The lowest detection limit (logaCs+ = -6.3) and the higher selectivity coefficient (logkpotCs+,Rb+ = -2.1 by SSM, -2.3 by FIM for calix[6]arene I) for Cs+ have been obtained for membranes containing quadruply-bridged calix[6]arenes (I, Ⅱ, Ⅲ), which have no para t-butyl substituents on the bridging benzene ring.

Polystyrene Supported Al(OTf)3: a Stable, Efficient, Selective, and Reusable Catalyst for Sulfonylation of Arenes with Sulfonic Acids

  • Boroujeni, Kaveh Parvanak
    • Bulletin of the Korean Chemical Society
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    • v.31 no.7
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    • pp.1887-1890
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    • 2010
  • Cross-linked polystyrene supported aluminium triflate (Ps-Al(OTf)$_3$) was found to be an efficient and chemoselective heterogeneous Lewis acid catalyst for the direct conversion of arenes to sulfones using sulfonic acids as sulfonylating agents. The solid acid catalyst is stable (as a bench top catalyst) and can be easily recovered and reused without appreciable change in its efficiency.

Conformations of 25,27-Diacyloxy-26,28-dialkyloxycalix[4]arenes

  • Kwanghyun No;Hee Jung Koo;Min Seong Lee
    • Bulletin of the Korean Chemical Society
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    • v.15 no.9
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    • pp.791-795
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    • 1994
  • 1,3-Dimethyl and dipropyl ethers of p-t-butylcalix[4]arene and calix[4]arenes have been converted to the corresponding diesters, acetate and propionate, and their conformations are inferred based on the $^1H$ and $^{13}C$ NMR spectra. The presence of t-butyl groups is effective in maintaining the cone conformation on derivatization.