title: L-Glutamic acid and L-lysine as useful building blocks for the preparation of bifunctional DTPA-like ligands.
abstract: Bisalkylation of suitably protected L-glutamic acid and L-lysine derivatives with tert-butyl N-(2-bromoethyl)iminodiacetate 2, followed by deprotection of the omega functional group affords N, N-bis[2-[bis[2-(1, 1-dimethylethoxy)-2-oxoethyl]amino]ethyl]-L-glutamic acid 1-(1, 1-dimethylethyl) ester 4 and N2,N2-bis[2-[bis[2-(1, 1-dimethylethoxy)-2-oxoethyl]amino]ethyl]-L-lysine 1,1-dimethylethyl ester 7. Such compounds feature a carboxylic or an amino group, respectively, which are available for conjugation with a suitable partner via formation of an amide bond. The conjugates, which can be prepared in this way, contain a chelating subunit in which all five acetic residues of DTPA are available for the complexation of metal ions. Direct bisalkylation of glycine with 2 promptly gives N, N-bis[2-[bis[2-(1,1-dimethylethoxy)-2-oxoethyl]amino]ethyl]glycine 11. The latter allows to achieve conjugates in which the central acetic group of DTPA is selectively converted into an acetamide.
authors.affiliation: Bracco spa, Milano Research Centre, via E. Folli 50, 20134 Milano, Italy.
authors.forename: P L
authors.initials: PL
authors.lastname: Anelli
authors.forename: F
authors.initials: F
authors.lastname: Fedeli
authors.forename: O
authors.initials: O
authors.lastname: Gazzotti
authors.forename: L
authors.initials: L
authors.lastname: Lattuada
authors.forename: G
authors.initials: G
authors.lastname: Lux
authors.forename: F
authors.initials: F
authors.lastname: Rebasti
mesh_terms: D000478:Alkylation; D002614:Chelating Agents / Q000138:chemical synthesis* / Q000737:chemistry; D018698:Glutamic Acid / Q000737:chemistry*; D008024:Ligands; D008239:Lysine / Q000737:chemistry*; D004369:Pentetic Acid / Q000737:chemistry*
chemical_list: D002614:Chelating Agents; D008024:Ligands; D018698:Glutamic Acid; D004369:Pentetic Acid; D008239:Lysine