The synthesis and NMR elucidation of Ala-Val-Pro-Ile and five novel peptide-based derivatives are reported. These peptides mimic the natural second mitochondria-derived activator of caspase (Smac) protein. Purification was achieved using preparative HPLC and the NMR elucidation of all compounds is reported for the first time. A series of overlapping signals were observed in the 1D NMR spectra thus making assignment a difficult task to undertake. The use of 2D NMR techniques with the inclusion of efficient adiabatic symmetrized ROESY proved to be an effective tool in overcoming these difficulties. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.