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Updated: Apr 24, 2026
Constructing Cyclic Peptides Using an On-Tether Sulfonium Center
Published on: September 28, 2022
Peptide coupling between amino acids and the carboxylic acid of a functionalized chlorido-gold(I)-phosphane
Margit Kriechbaum1, Manuela List, Markus Himmelsbach
1Institute of Inorganic Chemistry, ‡Institute for Chemical Technology of Organic Materials, and §Institute for Analytical Chemistry, Johannes Kepler University Linz , Altenbergerstrasse 69, 4040 Linz, Austria.
Abstract:
We have developed a protocol for the direct coupling between methyl ester protected amino acids and the chlorido-gold(I)-phosphane (p-HOOC(C6H4)PPh2)AuCl. By applying the EDC·HCl/NHS strategy (EDC·HCl = N-ethyl-N'-(3-(dimethylamino)propyl)carbodiimide hydrochloride, NHS = N-hydroxysuccinimide), the methyl esters of l-phenylalanine, glycine, l-leucine, l-alanine, and l-methionine are coupled with the carboxylic acid of the gold complex in moderate to good yields (62-88%). All amino acid tagged gold complexes were characterized by (1)H and (13)C NMR spectroscopy and high-resolution mass spectrometry. As corroborated by measurement of the angle of optical rotation, no racemization occurred during the reaction. The molecular structure of the leucine derivative was determined by single-crystal X-ray diffraction. In the course of developing an efficient coupling protocol, the acyl chlorides (p-Cl(O)C(C6H4)PPh2)AuX (X = Cl, Br) were also prepared and characterized.
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