Synthesis and Conformational Analysis of 1:1 [α/α‐Nα‐Bn‐Hydrazino] and 1:1 [α‐Nα‐Bn‐Hydrazino/α] Trimers: Determination of the Δδ Value for the γ‐Turn Structuration

Heterogeneous 1:1 [/-N-Bn-hydrazino] pseudopeptides are able to self-organize in CDCl3 solution by an alternation of the -turn and hydrazinoturn conformations. Amidation of the C terminus allowed us to calculate the difference in the chemical shift () of the H-1 NMR signals of the geminal amidic protons and to associate a value from 2.58 to 2.75 ppm with the presence of a hydrazinoturn at the C terminus. In this paper we wish to demonstrate that the measurement of a value close to 0.9 ppm can be correlated with the presence of a -turn structuration. This result will complete this valuable toolbox of values for a rapid access to the self-organization of pseudopeptides involving hydrazinoturns and/or -turns based on simple and accessible H-1 NMR experiments, and should also provide an opportunity to extend the scope of heterogeneous backbone foldamer design.