Solid-phase synthesis, cyclization, and site-specific functionalization of aziridine-containing tetrapeptides.

Area of Science:

• Medicinal Chemistry
• Organic Synthesis
• Peptide Chemistry

Background:

• Cyclic tetrapeptides exhibit diverse biological activities, including phytotoxicity and histone deacetylase (HDAC) inhibition.
• Incorporating aziridine groups into cyclic peptides offers conformational control and enables site-selective functionalization for covalent protein labeling.

Purpose of the Study:

• To describe a protocol for the solid-phase synthesis, cyclization, and modification of aziridine-containing tetrapeptides.
• To establish a faster and more efficient method for generating these valuable molecular scaffolds.

Main Methods:

• Solid-phase peptide synthesis using Fmoc-protected amino acids to assemble linear precursors.
• Head-to-tail cyclization using a slow reverse-addition method to prevent side products.
• Site-specific modification of macrocycles with reagents like sodium azide or thiophenol.

Main Results:

• The protocol yields aziridine-containing peptide macrocycles in approximately 4 days, significantly faster than conventional solution-phase methods (3 weeks).
• Demonstrated site-specific functionalization of the synthesized macrocycles.
• Addressed critical handling considerations for electrophilic aziridine functionalities.

Conclusions:

• This protocol provides efficient access to aziridine-containing macrocyclic peptides.
• These scaffolds are valuable for drug discovery and molecular probe development due to their potential for covalent protein labeling.
• The developed method accelerates the synthesis of these important compounds, facilitating further research.