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New lipophilic crown ethers with intraannular carboxylic acid groups: Synthesis and alkali metal cation extraction
Author(s) -
Bratton Larry D.,
Huh Hwang,
Bartsch Richard A.
Publication year - 2000
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570370424
Subject(s) - chemistry , alkali metal , carboxylic acid , extraction (chemistry) , crown (dentistry) , organic chemistry , crown ether , ion , medicine , dentistry
A six‐step synthetic route to four lipophilic crown ethers with intraannular carboxylic acid groups and ring sizes of 15‐crown‐4, 18‐crown‐5, 21‐crown‐6 and 24‐crown‐7 is described. Eight new polyether compounds that bear inward‐facing bromo and formate ester substituents are prepared as synthetic intermediates. Selectivities and efficiencies of the four new lipophilic crown ether carboxylic acids in competitive alkali metal cation extraction from aqueous solutions into chloroform are evaluated.