Facile Syntheses of Dibenzo-14-crown-4^1a and bis-butylbenzo-14-crown-4^1b

Abstract

Although there is a wide interest in the syntheses of macrocyclic compounds, since Pedersen's² and Lehn's³ introduction that they are capable of forming stable complexes with the alkali ions, only few attentions have been given to utilize crown-4 as complexing agents.^4–7 However, the unsubstituted 12-crown-4^1c appeared to be a good complexing agent which forms a 1:1 complex with lithium cation.^6,7 Recently, we were interested in the synthesis of dibenzo-14-crown-4 with alkyl substituents on benzo groups and utilizing it as an extracting agent for selectively extracting lithium cation from aqueous solution.⁸