Sodium amalgam: A highly efficient reagent for the detosylation of azathiacrown ethers

摘要

A simple, nearly quantitative method is demonstrated for the deprotection of tosylated mixed azathiacrown ethers using sodium amalgam. Four macrocycles, containing differing numbers of amino groups and ring sizes, were prepared using traditional cyclization procedures and the described deprotection technique. Three of the macrocycles, [12] aneNS(3), [14]aneNS(3), and [15]aneN(2)S(3), were reported previously, though either in low yields, only in protected form, or using hazardous precursors, while the fourth, [18]aneN(3)S(3), is a new ionophore.