Exploring the Conformation of Mixed Cis- Trans α,β-Oligopeptoids: A Joint Experimental and Computational Study

J Org Chem. 2018 Jun 15;83(12):6382-6396. doi: 10.1021/acs.joc.8b00606. Epub 2018 Jun 4.

Abstract

The synthesis and conformational preferences of a set of new synthetic foldamers that combine both the α,β-peptoid backbone and side chains that alternately promote cis- and trans-amide bond geometries have been achieved and addressed jointly by experiment and molecular modeling. Four sequence patterns were thus designed and referred to as cis-β- trans-α, cis-α- trans-β, trans-β- cis-α, and trans-α- cis-β. α- and β NtBu monomers were used to enforce cis-amide bond geometries and α- and β NPh monomers to promote trans-amides. NOESY and molecular modeling reveal that the trans-α- cis-β and cis-β- trans-α tetramers show a similar pattern of intramolecular weak interactions. The same holds for the cis-α- trans-β and trans-β- cis-α tetramers, but the interactions are different in nature than those identified in the trans-α- cis-β-based oligomers. Interestingly, the trans-α- cis-β peptoid architecture allows establishment of a larger amount of structure-stabilizing intramolecular interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Biopolymers / chemistry
  • Carbon-13 Magnetic Resonance Spectroscopy
  • Computer Simulation*
  • Crystallography, X-Ray
  • Molecular Conformation
  • Molecular Dynamics Simulation
  • Peptoids / chemistry*
  • Proton Magnetic Resonance Spectroscopy
  • Quantum Theory
  • Spectrometry, Mass, Electrospray Ionization

Substances

  • Biopolymers
  • Peptoids