Proton NMR studies of partially modified retro–inverso peptides

High‐resolution ¹H‐nmr analyses are presented for partially modified retro‐inverso derivatives of peptides with emphasis on enkephalins. Studies in DMSO‐d₆ reveal the unique as well as common characteristics of the non‐amino acid residues incorporated into these modified peptides. The complete assignment of 1,1‐diaminoalkyl and malonyl, as well as of amino acid, residues provides the basis for the exploration of the conformational features induced in peptides by such topochemical modifications.