Synthesis and characterization of calixarene analogs locked in the cone conformation by the dimerization of syn-dihydroxymetacyclophanes as a building block
摘要:
syn-Dihydroxymetacyclophanes were converted to bridged calix[4]arene analogs by base-catalyzed condensation with formaldehyde. A remarkable template effect was observed on this condensation. Enlarged calix[4]arene analogs were synthesized by two different methods. All calix[4]arene analogs took the cone-type conformation and kept it even at high temperatures, according to the elucidation by H-1 NMR spectroscopy. The acidities (pKapp) of calix[4]arene analogs, which partially form the hydrogen bonding, were medium values in the range of 5.1-5.5. Calix[4]arene analogs can transport Li+ ion considerably and show the selectivity for Li+ over Na+ ions 15 and 30 in the weak basic and neutral solutions, respectively. (C) 2001 Elsevier Science Ltd. All rights reserved.
Synthesis and characterization of calixarene analogs locked in the cone conformation by the dimerization of syn-dihydroxymetacyclophanes as a building block
摘要:
syn-Dihydroxymetacyclophanes were converted to bridged calix[4]arene analogs by base-catalyzed condensation with formaldehyde. A remarkable template effect was observed on this condensation. Enlarged calix[4]arene analogs were synthesized by two different methods. All calix[4]arene analogs took the cone-type conformation and kept it even at high temperatures, according to the elucidation by H-1 NMR spectroscopy. The acidities (pKapp) of calix[4]arene analogs, which partially form the hydrogen bonding, were medium values in the range of 5.1-5.5. Calix[4]arene analogs can transport Li+ ion considerably and show the selectivity for Li+ over Na+ ions 15 and 30 in the weak basic and neutral solutions, respectively. (C) 2001 Elsevier Science Ltd. All rights reserved.
The selective extraction and transport of amino acids by calix[4]arene-derived esters
作者:Yukihiro Okada、Yoshinori Kasai、Jun Nishimura
DOI:10.1016/0040-4039(94)02251-6
日期:1995.1
New calix[4]arene analogs having chiral pendant groups efficiently extracted Phe, Phg, and Trp esters as well as their Z-carboxylates. These receptors also recognized the chirality of the L-amino acids in transport experiments.
The modification of title compounds to chiral receptors and their characterization are reported. The tno synthetic methods were developed The racemates obtained could be resolved to each stable enantiomer by achiral HPLC column. Chiral calixarenes were designed as the receptors with planar chirality. The (-)-receptor strongly forms 1:1 complex with (R)-(+)-alpha-phenylethylammonium picrate. (C) 1997 Elsevier Science Ltd.