Stereoselective synthesis and conformational analysis of pseudo-heptapeptides: Part 5

The stereoselective synthesis of pseudo-heptapeptides 8, 9 and 12, incorporating a 2,6-diamino-4-methylen-1,7-heptanedioic acid residue, was accomplished starting from chiral synthon 3, a masked unnatural dipeptide derived from an l-valine unit and (2R)-methylaspartic acid. Investigations of the conformational preference and structure of these unnatural peptides were carried out using 1H NMR and IR spectroscopic data and a conformational analysis based on molecular dynamics (MD).