title: Synthesis of a diaminedithiol bifunctional chelating agent for incorporation of technetium-99m into biomolecules.
abstract: The synthesis of a bifunctional chelating agent (BCA), 1, based on the diaminedithiol (DADT) ligand system, is described. The six-step synthetic sequence has been accomplished in 16% overall yield, affording 1, which contains a thiolactone as a reactive moiety, which permits direct coupling to nucleophiles without the formation of byproducts. The reactivity of 1 toward benzylamine and subsequent labeling of the ligand with technetium-99m has been evaluated as a model for preparation of various bioconjugates. Both coupling and exchange labeling occur in high yield under mild conditions, and competition reactions with diethylenetriaminepentaacetic acid (DTPA) indicate the superior stability of the technetium-99m-DADT complex. Preparation of BCA 1 thus provides a new avenue into technetium-labeled radiopharmaceuticals.
authors.affiliation: Department of Environmental Health Sciences, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland 21205-2179.
authors.forename: K E
authors.initials: KE
authors.lastname: Baidoo
authors.forename: S Z
authors.initials: SZ
authors.lastname: Lever
mesh_terms: D002614:Chelating Agents / Q000138:chemical synthesis* / Q000737:chemistry; D003959:Diamines; D007202:Indicators and Reagents; D007700:Kinetics; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D004369:Pentetic Acid; D013055:Spectrophotometry, Infrared; D013438:Sulfhydryl Compounds; D013667:Technetium
chemical_list: D002614:Chelating Agents; D003959:Diamines; D007202:Indicators and Reagents; D008024:Ligands; D013438:Sulfhydryl Compounds; D013667:Technetium; D004369:Pentetic Acid