Authors Gube, A. ; Komber, H. ; Sahre, K. ; Friedel, P. ; Voit, B. ; Böhme, F.
Title Formation of oligomeric and macrocyclic ureas based on 2,6-diaminopyridine
Date 08.11.2012
Number 34183
Abstract The conversion of 1,3-bis-(6-amino-pyridin-2-yl)-urea (1) with N,N'-carbonyldiimidazole at high temperatures in DMSO yielded a mixture of defined cyclic trimers and tetramers. On the basis of model reactions, exchange reactions were evidenced, which convert the cyclic tetramer into a stable cyclic trimer. Linear even numbered oligomers were obtained in acetone under reflux where side reactions were suppressed. The pronounced tendency of cyclization is attributed to a preferred folded conformation of the urea bond between two pyridyl units.
Publisher Journal of Organic Chemistry
Citation Journal of Organic Chemistry 77 (2012) 9620-9627
Tags oligopyridine-dicarboxamide strands single helical structures oligo(phenanthroline dicarboxamide)s heterocyclic ureas foldamers naphthyridine system amide

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