Rotaxanes of cyclic peptides

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Peptide Chemistry

Background:

• Rotaxanes are mechanically interlocked molecular architectures with potential applications in molecular machines.
• Peptide macrocycles offer unique structural and functional properties for supramolecular assembly.
• Internal hydrogen bonding within macrocycles can influence their conformational flexibility and reactivity.

Purpose of the Study:

• To synthesize novel rotaxanes utilizing specific peptide macrocycles.
• To investigate the formation of rotaxanes from cyclo(l-ProGly)4 and cyclo(l-ProGly)5 macrocycles and diammonium threads.
• To assess the yields and structural integrity of the synthesized rotaxanes.

Main Methods:

• Template-directed synthesis of rotaxanes.
• Utilizing cyclo(l-ProGly)4 and cyclo(l-ProGly)5 as macrocyclic components.
• Employing diammonium derivatives as molecular threads.

Main Results:

• Successful synthesis of rotaxanes was achieved in good yields, ranging from 56% to 63%.
• The formation of rotaxanes occurred despite the inherent disruption of internal amide-amide hydrogen bonding within the peptide macrocycles.
• The study demonstrates the feasibility of constructing complex rotaxane architectures from peptide-based macrocycles.

Conclusions:

• Peptide macrocycles, including cyclo(l-ProGly)4 and cyclo(l-ProGly)5, can serve as effective components for rotaxane synthesis.
• The synthetic strategy allows for the formation of rotaxanes even when non-covalent interactions within the macrocycle are compromised.
• This work expands the scope of accessible rotaxane structures and highlights the versatility of peptide macrocycles in supramolecular chemistry.