title: Peptide coupling between amino acids and the carboxylic acid of a functionalized chlorido-gold(I)-phosphane.
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.
authors.affiliation: Institute of Inorganic Chemistry, ‡Institute for Chemical Technology of Organic Materials, and §Institute for Analytical Chemistry, Johannes Kepler University Linz , Altenbergerstrasse 69, 4040 Linz, Austria.
authors.forename: Margit
authors.initials: M
authors.lastname: Kriechbaum
authors.forename: Manuela
authors.initials: M
authors.lastname: List
authors.forename: Markus
authors.initials: M
authors.lastname: Himmelsbach
authors.forename: Günther J
authors.initials: GJ
authors.lastname: Redhammer
authors.forename: Uwe
authors.initials: U
authors.lastname: Monkowius
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006046:Gold / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D002264:Carboxylic Acids; D002712:Chlorides; D010455:Peptides; D010720:Phosphines; D006046:Gold; C044646:phosphine