title: Carbohydrate-appended 2,2'-dipicolylamine metal complexes as potential imaging agents.
abstract: Three discrete carbohydrate-appended 2,2'-dipicolylamine ligands were complexed to the {M(CO)(3)}(+) (M = (99m)Tc/Re) core: 2-(bis(2-pyridinylmethyl)amino)ethyl-beta-d-glucopyranoside (L(1)()), 2-(bis(2-pyridinylmethyl)amino)ethyl-beta-D-xylopyranoside (L(2)()), and 2-(bis(2-pyridinylmethyl)amino)ethyl-alpha-d-mannopyranoside (L(3)). An ethylene spacer is used to separate the carbohydrate moiety and the dipicolylamine (DPA) function in all three ligands. The Re complexes [Re(L(1-3))(CO)(3)]Br were characterized by (1)H and (13)C 1D/2D NMR spectroscopies, which confirmed the pendant nature of the carbohydrate moieties in solution. NMR measurements also established the long-range asymmetric effect of the carbohydrate functions on the chelating portion of the ligand. One analogue, [Re(L(1))(CO)(3)]Cl, was characterized in the solid state by X-ray crystallography. Further characterization was provided by IR spectroscopy, elemental analysis, conductivity, and mass spectrometry. Radiolabeling of L(1)-L(3) with [(99m)Tc(H(2)O)(3)(CO)(3)](+) afforded high yield compounds of identical character to the Re analogues. The radiolabeled compounds were found to be stable toward ligand exchange in the presence of a large excess of either cysteine or histidine over a 24-h period.
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: Tim
authors.initials: T
authors.lastname: Storr
authors.forename: Yuko
authors.initials: Y
authors.lastname: Sugai
authors.forename: Cheri A
authors.initials: CA
authors.lastname: Barta
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mikata
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Adam
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Yano
authors.forename: Chris
authors.initials: C
authors.lastname: Orvig
mesh_terms: D000588:Amines / Q000737:chemistry*; D002241:Carbohydrates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D003952:Diagnostic Imaging; D005030:Ethylenes / Q000737:chemistry; D006639:Histidine / Q000737:chemistry; D007553:Isotope Labeling; D008024:Ligands; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D010848:Picolinic Acids / Q000737:chemistry*; D019275:Radiopharmaceuticals / Q000138:chemical synthesis*; D013997:Time Factors
chemical_list: C501847:2,2'-dipicolylamine; D000588:Amines; D002241:Carbohydrates; D005030:Ethylenes; D008024:Ligands; D009942:Organometallic Compounds; D010848:Picolinic Acids; D019275:Radiopharmaceuticals; D006639:Histidine; C036216:ethylene; D003545:Cysteine