Inverse Peptide Synthesis Using Transient Protected Amino Acids.

Area of Science:

• Organic Chemistry
• Medicinal Chemistry
• Green Chemistry

Background:

• Peptide therapeutics are experiencing a resurgence, driving demand for efficient manufacturing.
• Conventional peptide synthesis (C → N) relies on protecting groups, leading to poor step- and atom-economy.
• Inverse peptide synthesis (N → C) using unprotected amino acids is desirable but plagued by racemization.

Purpose of the Study:

• To develop a cost-effective and environmentally friendly peptide manufacturing strategy.
• To overcome the long-standing challenge of racemization in inverse peptide synthesis.
• To enable practical peptide synthesis using unprotected amino acids.

Main Methods:

• Development of a novel ynamide coupling reagent.
• Implementation of a transient protection strategy for one-pot activation, protection, aminolysis, and deprotection.
• Demonstration of robustness through synthesis of peptide active pharmaceutical ingredients.

Main Results:

• Successfully addressed racemization/epimerization issues in N → C peptide chain elongation.
• Achieved practical peptide synthesis using unprotected amino acids as starting materials.
• Demonstrated compatibility with green solvents for large-scale production and fragment condensation.

Conclusions:

• The ynamide coupling reagent with transient protection offers a practical solution for inverse peptide synthesis.
• This method provides a cost-effective, operationally convenient, and environmentally benign approach to peptide manufacturing.
• The strategy enhances the potential for large-scale production of peptide therapeutics.