Conformational behavior of 1:1 [α/α-Hydrazino]mer, 1:1 [α/Aza-β3-amino]mer and 1:1 [Aza-β3-amino/ α]mer series: Three series of foldamers

Article abstract of DOI:10.1002/ejoc.201300567

Analysis of ¹H NMR spectroscopic data allowed us to assign the secondary structure of three new series of mixed foldamers. 1:1 [α/aza-β³-amino]mers, 1:1 [aza-β³-amino/ α]mers and 1:1 [α/α-hydrazino]mers are self-organized in solution by a hydrogen bond network of alternating a γ-turn and a hydrazinoturn. Nevertheless, owing to the donor and acceptor H-bond characters of the amidic NH, 1:1 [α/α-hydrazino]mers can exist as an equilibrium between pseudospiranic and hydrazinoturn conformations. We describe the synthesis of 1:1 [α/α-hydrazino]mer, 1:1 [α/aza- β³-amino]mer and 1:1 [aza-β³-amino/α]mer series and analyze their ¹H NMR spectroscopic data to understand their conformational behavior. This study shows that all series are self-organized as γ-turn and hydrazinoturns. For 1:1 [α/α- hydrazino]mers the sp³ N^α allowed an equilibrium between this conformation and a pseudospiranic one. Copyright