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Updated: Jul 10, 2026
11:44
Synthesis and Structure Determination of µ-Conotoxin PIIIA Isomers with Different Disulfide Connectivities
Published on: October 2, 2018
The depsipeptide technique applied to peptide segment condensation: scope and limitations
Irene Coin1, Peter Schmieder, Michael Bienert
1Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125 Berlin, Germany. coin@fmp-berlin.de
Summary
Depsipeptide coupling offers efficient peptide synthesis without epimerization. Optimizing conditions prevents beta-elimination, enabling faster and configurationally stable peptide segment condensation.
Area of Science:
- Organic Chemistry
- Peptide Chemistry
- Synthetic Chemistry
Background:
- Depsipeptide technique offers advantages for peptide segment condensation.
- Avoids epimerization common in traditional peptide coupling methods.
- Low tendency of activated depsipeptide units to form optically labile oxazolones.
Purpose of the Study:
- To investigate the efficiency and limitations of depsipeptide coupling.
- To identify optimal conditions for suppressing side reactions like beta-elimination.
- To compare depsipeptide coupling with C-terminal pseudoprolines.
Main Methods:
- Base-assisted activation using HBTU (hexafluorophosphate benzotriazole tetramethyl uronium).
- Carbodiimide/HOBt (hydroxybenzotriazole) activation.
- Varied solvent systems (DCM, DMSO/toluene) and bases (DIEA, TMP).
Main Results:
- Depsipeptide coupling via HBTU is faster and configurationally stable compared to all-amide segments.
- Beta-elimination observed in slow couplings, dependent on base and solvent.
- Beta-elimination suppressed using carbodiimide/HOBt in DCM or modified HBTU/carbodiimide conditions.
- C-terminal pseudoprolines evaluated for segment coupling.
Conclusions:
- Depsipeptide coupling is a viable method for stereoselective peptide synthesis.
- Careful selection of activation reagents and solvents is crucial to prevent beta-elimination.
- Depsipeptide units and pseudoprolines offer alternative strategies for peptide segment coupling.
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