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Bee Cave, TX, United States

Hanes R.E.,Beacon science LLC | Ellingsworth E.C.,University of Alabama | Griffin S.T.,University of Alabama | Rogers R.D.,University of Alabama | Bartsch R.A.,Texas Tech University
Arkivoc | Year: 2010

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. Source


Hanes R.E.,Beacon science LLC | Lee J.C.,Texas Tech University | Ivy S.N.,Texas Tech University | Palka A.,Texas Tech University | Bartsch R.A.,Texas Tech University
Arkivoc | Year: 2010

Macrocyclization of crown ethers and their methods of preparation were explored. We present a robust, scalable method for the preparation of these macrocycles. Additionally, the effect of changing the structures of the precursors was explored to determine whether the 'cut' of bisphenol and dimesylate influenced the course of the reaction as measured by the yield. Further, using catechol derivatives, the method was used for the preparation of monobenzocrown ethers. Interestingly, for the preparation of monobenzocrown ethers, [2+2] adducts were discovered to be significantly contaminating the products. Dimesylates were chosen as the leaving group due to their ease or preparation and the ability to use the unpurified products with no apparent impact on the macrocyclization. Source


Boston A.L.,Texas Tech University | Boston A.L.,Beacon science LLC | Lee E.K.,Texas Tech University | Lee E.K.,Beacon science LLC | And 6 more authors.
Tetrahedron | Year: 2012

New di-ionizable p-tert-butylcalix[4]arene-1,2-crown-4 ligands with elongated side arms in cone, partial-cone, and 1,2-alternate conformations of the calixarene scaffold are prepared and characterized. The acidic groups on the side arms include carboxylic acid and N-(X)sulfonyl carboxamide with X variation of -Me, -Ph, -C 6H 4-4-NO 2, and -CF 3. Solvent extractions of alkaline earth metal cations, Hg 2+, and Pb 2+ from aqueous solutions into chloroform are employed to probe the effects of these structural modifications on the divalent metal ion complexation behavior of the new ligands. © 2012 Elsevier Ltd. All rights reserved. Source

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