52601-78-2Relevant articles and documents
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.
Polycarboxylate diaza crown ethers derived from R,R-(+)-tartaric acid: synthesis and complexation of metal ions
Anantanarayan, Ashok,Fyles, Thomas M.
, p. 1338 - 1351 (2007/10/02)
The synthesis and complexation properties of polycarboxylate diaza crown ethers based on R,R-(+)-tartaric acid are described.Cesium carbonate mediated macrocyclization of a bis-tosylamide precursor with a bis-tosylate precursor provided the protected crown ethers.Photochemical deprotection of the tosylamides and hydrolysis of the carboxamides yielded dicarboxylic and tetracarboxylic acid derivatives of 1,10-diaza-18-crown-6.N-Methylenecarboxylate (N-acetate) derivatives were prepared by N-alkylation with bromoacetic acid.The synthetic and purification procedures developed provide samples of the ligands in a metal-free form.Acidity and stability constants for complexation of alkali metal, alkaline earth, late- and post-transition metal cations were determined by potentiometric titration.The ligands form complexes which show enhancement of stability by charge-charge and chelate interaction with the carboxylates.In comparison with crown ether polycarboxylates these aza crown ethers showed a selectivity for softer metal ions relative to alkali and alkaline earth metal ions.N-Methylenecarboxylate chelate ligands were found to bind almost all types of metal ions, due to a highly co-operative array of charge-charge, chelate and crown ether interactions.
MACROHETEROCYCES. XXXVI. A CONVENIENT METHOD FOR SYNTHESIS OF DI- AND POLYAZACROWN ETHERS
Luk'yanenko, N.G.,Basok, S.S.,Filonova, L.K.
, p. 1562 - 1571 (2007/10/02)
A method is proposed for the production of di- and polyazacrown ethers by the condensation of bissulfonamides with dibromides or ditosyloxy derivatives in a two-phase aqueous alkali-toluene (benzene) system.The optimum concentration range for the substrate and the alkylating agent is 0.017-0.1 M.The catalytic activity of the quaternary ammonium salts decreases in the order (Bu)4NI > (Bu4)NBr > (Bu4)NCl > (Bu4)NHSO4 > (C2H5)3C6H5CH2NCl >> (Et)4NI > (Et)4NBr.The highest yields of te 12-membered azacrown ethers are obtained in the presence of lithium hyroxide, and the largest yields of the crown ethers with larger ring sizes are obtained in the presence of sodium or potassium hydroxide, and this is probably due to the matrix effects of the cation.