Facile formation of pyroglutamic peptides from glutamic acid

ORGN 155

Parul Angrish, pangrish@chem.ufl.edu, Ekaterina Todadze, and Ion Ghiviriga. Department of Chemistry, Organic Division, University of Florida, PO Box 117200, Gainesville, FL 32611-7200
Glutamic acid has the ability to demonstrate interesting chemistry and has a role in protein's post translational modifications due to the presence of &alpha- and &gamma-COOH functionality. In this study, we explored its reactivity at these two different functional sites. Herein, we showed that there was facile formation of natural or unnatural peptides when the other -COOH group was protected. However, when both of the -COOH groups were activated simultaneously, we observed that the activated &alpha–COOH underwent peptide coupling while the activated &gamma-COOH exhibited cyclization, consequently yielding pyroglutamic dipeptides. These results were also supported by 2D-NMR studies. These studies were carried out under the able guidance of Prof. A. R. Katritzky.