Preferred conformation of peptides from Cα,α‐symmetrically disubstituted glycines: Aromatic residues

Abstract

The conformational preference of C^α,α‐diphenylglycinc (Døg) and C^α,α‐dibenzylglycine (Dbz) residues was assessed in selected derivatives and small peptides by conformational energy computations, ir absorption, ¹H‐nmr, and x‐ray diffraction. Conformational energy computations on the two monopeptides strongly support the view that these C^α,α‐symmetrically disubstituted glycines are conformationally restricted and that their minimum energy conformation falls in the fully extended (C₅) region. The results of the theoretical analyses appear to be in agreement with the solution and crystal‐state structural propensities of three derivatives and seven di‐and tripeptides.