title: o-Boronato- and o-Trifluoroborato-Phosphonium Salts Supported by L-α-Amino Acid Side Chain.
abstract: The synthesis of o-boronato- and o-trifluoroborato-phosphonium salts supported by the L-amino acid side chain is described. The synthesis of these new class of amino acid derivatives was achieved by stereoselective quaternization of o-(pinacolato)boronatophenylphosphine with β- or γ-iodo amino acid derivatives which are prepared from L-serine or L-aspartic acid, respectively. The quaternization of the phosphine was performed using either iodo amino ester or carboxylic acid derivatives. In addition, free carboxylic acid and amine derivatives were obtained by saponification or HCl acidolysis of o-boronato-phosphonium amino esters, respectively. The usefulness of these compounds in peptide coupling was demonstrated by coupling an o-boronato-phosphonium amino ester with an aspartic acid moiety. When the o-boronato-phosphonium amino acid or dipeptide derivatives were mixed with fluoride, the corresponding o-trifluoroborated products were cleanly and rapidly obtained in high isolated yields. The hydrolysis of these compounds at room temperature using a phosphate buffer pH 7/CD3CN mixture has shown only traces of free fluoride F(-) after several days. Finally, a preliminary radiolabeling essay has proven the facile [(18)F]-fluoride incorporation and high stability of the radiolabeled product in aqueous conditions. Indeed, this new class of boron-phosphonium amino acid derivatives shows promising properties for their applications in synthesis and labeling of peptides.
authors.affiliation: †Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB) StéréochIM UMR CNRS 6302, 9 Avenue A. Savary BP 47870, 21078 Dijon Cedex, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Bernard
authors.affiliation: †Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB) StéréochIM UMR CNRS 6302, 9 Avenue A. Savary BP 47870, 21078 Dijon Cedex, France.
authors.forename: Raluca
authors.initials: R
authors.lastname: Malacea-Kabbara
authors.affiliation: ‡Department of Chemistry and Positron Emission Tomography Research Centre, University of Hull, Cottingham Road, Hull, East Yorkshire HU6 7RX, United Kingdom.
authors.forename: Gonçalo S
authors.initials: GS
authors.lastname: Clemente
authors.affiliation: ‡Department of Chemistry and Positron Emission Tomography Research Centre, University of Hull, Cottingham Road, Hull, East Yorkshire HU6 7RX, United Kingdom.
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Burke
authors.affiliation: †Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB) StéréochIM UMR CNRS 6302, 9 Avenue A. Savary BP 47870, 21078 Dijon Cedex, France.
authors.forename: Marie-Joëlle
authors.initials: MJ
authors.lastname: Eymin
authors.affiliation: ‡Department of Chemistry and Positron Emission Tomography Research Centre, University of Hull, Cottingham Road, Hull, East Yorkshire HU6 7RX, United Kingdom.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Archibald
authors.affiliation: †Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB) StéréochIM UMR CNRS 6302, 9 Avenue A. Savary BP 47870, 21078 Dijon Cedex, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Jugé
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D001881:Borates / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D009943:Organophosphorus Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D012492:Salts / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D000596:Amino Acids; D001881:Borates; D009943:Organophosphorus Compounds; D012492:Salts