| Autor: |
Keyes ED; Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States., Mifflin MC; Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States., Austin MJ; Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States., Alvey BJ; Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States., Lovely LH; Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States., Smith A; Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States., Rose TE; 1200 Pharma LLC, 6100 Bristol Parkway, Culver City, California 90230, United States., Buck-Koehntop BA; Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States., Motwani J; Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States., Roberts AG; Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States. |
| Abstrakt: |
Inspired by nature's wide range of oxidation-induced modifications to install cross-links and cycles at tyrosine (Tyr) and other phenol-containing residue side chains, we report a Tyr-selective strategy for the preparation of Tyr-linked cyclic peptides. This approach leverages N4-substituted 1,2,4-triazoline-3,5-diones (TADs) as azo electrophiles that react chemoselectively with the phenolic side chain of Tyr residues to form stable C-N1-linked cyclic peptides. In the developed method, a precursor 1,2,4-triazolidine-3,5-dione moiety, also known as urazole, is readily constructed at any free amine revealed on a solid-supported peptide. Once prepared, the N4-substituted urazole peptide is selectively oxidized using mild, peptide-compatible conditions to generate an electrophilic N4-substituted TAD peptide intermediate that reacts selectively under aqueous conditions with internal and terminal Tyr residues to furnish Tyr-linked cyclic peptides. The approach demonstrates good tolerance of native residue side chains and enables access to cyclic peptides ranging from 3- to 11-residues in size (16- to 38-atom-containing cycles). The identity of the installed Tyr-linkage, a stable covalent C-N1 bond, was characterized using NMR spectroscopy. Finally, we applied the developed method to prepare biologically active Tyr-linked cyclic peptides bearing the integrin-binding RGDf epitope. |
