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.
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.
Diazadibenzo-30-crown-10 derivatives as receptors for diquat
Anelli,Spencer,Stoddart
, p. 1569 - 1572 (2007/10/02)
-