Unveiling the conformational landscape of achiral all--butyl β-peptoids.

The synthesis and conformational study of -substituted β-alanines with -butyl side chains is described. The oligomers prepared by submonomer synthesis and block coupling methods are up to 15 residues long and are characterised by amide bonds in the -conformation. A conformational study comprising experimental solution NMR spectroscopy, X-ray crystallography and molecular modeling shows that despite their intrinsic higher conformational flexibility compared to their α-peptoid counterparts, this family of achiral oligomers adopt preferred secondary structures including a helical conformation close to that described with (1-naphthyl)ethyl side chains but also a novel ribbon-like conformation.

First series of -alkylamino peptoid homooligomers: solution phase synthesis and conformational investigation.

The synthesis and conformational analysis of the first series of peptoid oligomers composed of consecutive -(alkylamino)glycine units is investigated. We demonstrate that -(methylamino)glycine homooligomers can be readily synthesized in solution using -Boc--methylhydrazine as a peptoid submonomer and stepwise or segment coupling methodologies. Their structures were analyzed in solution by 1D and 2D NMR, in the solid state by X-ray crystallography (dimer ), and implicit solvent QM geometry optimizations.