Synthesis and ion selectivity of macrocyclic metacyclophanes analogous to spherand-type calixarenes |
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Authors: | Takehiko Yamato Masashi Yasumatsu Yoshiyuki Saruwatari Louis Korbla Doamekpor |
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Institution: | (1) Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo-machi 1, 840 Saga-shi, Saga, Japan |
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Abstract: | Novel macrocyclic compounds, hexahydroxy1.0.1.0.1.0]- (2b) and octahydroxy1.0.1.0.1.0.1.0]metacyclophane (2c) have been prepared in 50–70% yield by base-catalyzed condensation of 5,5 -di-tert-butyl-2,2 -dihydroxybiphenyl (1) with formaldehyde in refluxing xylene. An attempted alkylation of the flexible macrocycles2b and2c with ethyl bromoacetate in the presence of Cs2CO3 under acetonitrile reflux gave only one pure stereoisomer3 and4, respectively, while other possible isomers were not observed. The structural characterization of these products is also discussed. The two-phase solvent extraction data indicated that hexaethyl ester3 and octaethyl ester4 show strong metal affinity, comparable with that of the corresponding calixn]arenes, and a high K+ selectivity was observed for octaethyl ester4.1H-NMR titration of hexaethyl ester3 and octaethyl ester4 with KSCN clearly demonstrate that a 1 1 complex is formed which is stable on the NMR time scale.This paper is dedicated to the commemorative issue on the 50th anniversary of calixarenes. |
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Keywords: | Spherand-type calixarene ion selectivity diastereoselective functionalization |
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