1-Allyl- and 1-benzyl-3-methyl-1,2,3-triazolium salts via tandem click transformations

Abstract

A series of 1-allylated and 1-benzylated 1,2,3-triazoles with varying substituents at the 4-position were prepared in yields ranging from 74-98% using a two-step one-pot click transformation. This tandem reaction involved the nucleophilic substitution of allyl chloride and benzyl bromide with sodium azide to form organic azide intermediates followed by Cu-catalyzed Huisgen 1,3-dipolar cycloaddition with alkyne reactants in a single reaction pot without the need for sequentially separating reaction steps. 1-Allyl- and 1-benzyl-4-alkyl-1,2,3-triazoles possessing linear alkyl chains underwent efficient N-alkylation at the 3-position with methyl iodide, while tert-butyl and phenyl derivatives did not. Each of the 1-allyl- and 1-benzyl-3-methyl-4- alkyl-1,2,3-triazolium iodide salts prepared was a viscous liquid at room temperature with a stable shelf life. © 2010 Georg Thieme Verlag Stuttgart New York.