Hexapeptide-9 is a synthetic peptide containing Glutamine, Glycine and Proline residues.
For example, linear hexapeptide 9 was prepared by removing the –Troc protection on 3 to afford 7 and appending the glycine-pyrrole side chain 5 to give 8. After -Fmoc removal, coupling to 4 afforded the desired branched hexapeptide 9, with only the final cyclization and protection group removal remaining. However, compound 9 proved highly unstable and did not succumb to cyclization.
Curzon, S. S., Garcia, J. M., & Konopelski, J. P. (2015). Total synthesis of nominal cyclocinamide B and investigation into the identity of the cyclocinamides. Tetrahedron letters, 56(23), 2991-2994.