title: Solid-phase synthesis of arginine-containing peptides and fluorogenic substrates using a side-chain anchoring approach.
abstract: Attachment of an amino acid to a solid support by its side chain is sometimes necessary to take advantage of an alpha-carboxylic group available for diverse modifications, including the incorporation of a fluorophore for the preparation of fluorogenic substrates. In contrast to most other amino acids, anchoring the guanidinium group of an arginine to a resin requires the use of a supplementary linker. To avoid the usually multistep synthesis of such a linker as well as its difficult attachment to the guanidine group, we developed a simple method where the guanidine group is built on a Rink amide resin. Our strategy followed the steps of guanidine formation: (i) addition of an isothiocyanate derivative of ornithine to the amino group of a solid support, yielding Nomega-linked thiocitrulline; (ii) S-methylation of thiourea; (iii) guanidinylation using ammonium acetate. Cleavage of the resin generated the arginine-containing compound, the amine group of the resin becoming part of the guanidine. We have demonstrated the usefulness of this method by the synthesis of a series of fluorogenic substrates for trypsin-like serine proteases, which were obtained in high yield and purity. Then, our strategy also allowed generation from the same precursor differentially substituted arginine derivatives, including Nomega-methyl- and Nomega-ethylarginines. The ability to prepare such analogues together with the intermediates thiocitrulline and S-methylisothiocitrulline from a unique precursor while the alpha-amine and carboxylic groups remain available for modification also makes this method a powerful tool for combinatorial solid-phase synthesis of NO synthase inhibitors.
authors.affiliation: Laboratoire des Aminoacides Peptides et Protéines, CNRS UMR 5810, Universités Montpellier I et II, Faculté de Pharmacie, 15 avenue Charles Flahault, BP 14491, 34093 Montpellier cédex 5, France.
authors.forename: Abdallah
authors.initials: A
authors.lastname: Hamzé
authors.forename: Jean
authors.initials: J
authors.lastname: Martinez
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Hernandez
mesh_terms: D001120:Arginine / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D010455:Peptides; D001120:Arginine