72358-83-9Relevant articles and documents
Synthesis and metal ion complexation studies of proton-ionizable calix[4]azacrown ethers in the 1,3-alternate conformation
Kim, Jong Seung,Shon, Ok Jae,Ko, Jong Won,Cho, Moon Hwan,Yu, Ill Yong,Vicens, Jacques
, p. 2386 - 2392 (2007/10/03)
A series of novel N-chromogenic calix[4]arene azacrown ethers were synthesized as selective extractants of potassium ion. 1,3-Alternate calix[4]arene azacrown ethers were prepared by reacting 25,27-dipropyloxy- 26,28-bis(5-chloro-3-oxapentyloxy) calix[4]arenes with p-toluenesulfonamide in the presence of potassium carbonate. The coupling reaction of calix[4]arene azacrown ether with 2-hydroxy-5-nitrobenzyl bromide in the presence of triethylamine in THF gave the chromogenic calix[4]arene azacrown ether in moderate yield. These compounds show high potassium selectivity over other metal ions as shown by two-phase extraction, bulk liquid membrane, and 1H NMR studies on a ligand-metal complex. It is assumed that the OH of the chromogenic group attached on nitrogen can assist the complexation by encapsulation of the metal.
Design and synthesis of macrocyclic ligands for specific interaction with crystalline ettringite and demonstration of a viable mechanism for the setting of cement
Griffin, Jonathan L. W.,Coveney, Peter V.,Whiting, Andrew,Davey, Roger
, p. 1973 - 1981 (2007/10/03)
Cementitious materials are among those most widely used by mankind while being among the least well understood. The detailed physicochemical processes involved in the hydration and setting of cement slurries are very complex, and a clearly defined quantitative account is still lacking: indeed, even the composition of the cement powder itself is not known exactly. Still less has there been any understanding of the mechanism by which numerous known retarders of the cement setting process act. In this article, we detail the synthesis of novel macrocyclic organophosphonate retarders 1a and 2a which were developed by rational methods. Attempts to synthesise these compounds as phosphonate ester derivatives were universally unsuccessful, however direct modification of the parent hexaaza-(3) and trioxatriaza-18-crown-6 (5) derivatives was successful, to provide the phosphonic acids 1b and 2b respectively. Subsequent testing of these compounds showed their ability to inhibit the growth of crystalline ettringite and delay the setting of cement. These results support the hypothesis that the formation of crystalline ettringite is the rate determining step in the setting of cement.
Synthesis of Chiral Diaza-18-crown-6 Derivatives from Optically Active Diethanolamines
Vries, Erik F. J. de,Steenwinkel, Pablo,Brussee, Johannes,Kruse, Chris G.,Gen, Arne van der
, p. 4315 - 4325 (2007/10/02)
Homotopic 1,10-diaza-18-crown-6 derivatives with two, four, and six chiral centers have been prepared in optically active form from diethanolamines via a cyclization reaction with tosylates 39 and 48.The requisite optically active diethanolamines were prepared from chiral cyanohydrins and chiral ethanolamines by a one-pot Grignard-transimination-reduction or a one-pot reduction-transimination-reduction procedure.Yields were strongly affected by the size of the substituents α to the nitrogen atom.The stereoselectivity of the diethanolamine synthesis was found to depend on the configuration of the ethanolamine used.
An Alternative Synthesis of Cyclic Aza Compounds
Boerjesson, L.,Welch, C. J.
, p. 621 - 626 (2007/10/02)
A series of cyclic mono-, di- and poly-aza compounds has been synthesised in moderate to good yields by reaction of p-toluenesulfonamide and either α,ω-ditosylates or α,ω-dichlorides.
Lipophilic Cage Ligands Containing Two Tightly Connected 1,7-Dioxa-4,10-diazacyclododecane Rings: Synthesis and X-ray Structure of a Sodium Perchlorate Complex
Anelli, Pier Lucio,Montanari, Fernando,Quici, Silvio,Ciani, Gianfranco,Sironi, Angelo
, p. 5292 - 5298 (2007/10/02)
Sodium perchlorate complexes 2 of lipophilic macrotricyclic receptors 1 were obtained in high yield by following a synthetic route in which sodium cation acts as the templating agent in the last step.Complexes with several inorganic salts were directly prepared from the free ligands 1, obtained by decomplexation of 2, or via anionic exchange from the complexes 2.Extraction data of alkali halides under two-phase conditions (H2O-CHCl3) with ligand 1a showed a cation extraction selectivity order Na+ >> K+ > Li+.Under liquid-liquid two-phase conditions, ligands 1 proved to be effective phase-transfer catalysts in hydroxide ion initiated carbanion formation from very weak carbon acids.The sodium complex 2a was crystallographically characterized.The sodium cation is in a nonsymmetric cubic environment of four oxygen (Na O 2.46 Angstroem) and four nitrogen (Na N 2.79 Angstroem) atoms.
Synthesis of a Cation Complexing Doubly N,N'-Bridged Bis-(1,7-dioxa-4,10-diazacyclododecane)
Calverley, Martin J.,Dale, Johannes
, p. 1084 - 1086 (2007/10/02)
Two molecules of diaza-12-crown-4 can be linked by two ethylene bridges between nitrogen atoms in two controlled steps, the last of which needs Li cation as a template, although Na cation is most strongly complexed by the tricyclic cryptand-like product.
