DefinitionĬhEBI: A saturated organic heteromonocyclic parent that is cyclopentadecane in which the carbon atoms at positions 1, 4, 7, 10 and 13 have been replaced by oxygen atoms to give a crown ether. Further, it is involved in the Horner-Wadsworth-Emmons reaction to prepare stilbenes from aldehydes.
It is used with lithium aluminum hydride, for performing reduction reactions in hydrocarbon solvents. It is also used to facilitate the Williamson synthesis of ethers with hindered alcohols and sodium hydride.
It catalyzes the O-alkylation of the sodium salts of carboxylic acids in the penicillin and cephalosporin series, thereby facilitating esterification reaction without usage of acid. It is used to isolate oxonium ion (H7O3)+ salts especially from a solution of tetrchloroauric acid. Chemical Propertiesġ5-Crown-5 is used as an efficient phase transfer catalyst and as a complexing agent. The term “monoazacrowns” is used here to designate the class of macrocycles containing a single nitrogen in combination with oxygen atoms as the macrocyclic donor array. When two or more nitrogen atoms are present, the standard prefixes di-, tri-, etc.
The single nitrogen-containing derivative of 15-crown-5 is called aza-15-crown-5 the prefix “mono” is unnecessary. For example, from a solution of tetrachloroauric acid, the oxonium ion + has been isolated as the salt. 15-crown-5 has also been used to isolate salts of oxonium ions.
