title: Radioiodination of 1-(2-deoxy-beta-D-ribofuranosyl)-2,4-difluoro-5-iodobenzene (dRFIB), a putative thymidine mimic nucleoside for cell proliferation studies.
abstract: Iodine-124 was produced via the (124)Te(p,n)(124)I reaction by 15 MeV proton irradiation of an in-house solid mass tellurium dioxide target, using the Tübingen PETtrace (General Electric Medical Systems) cyclotron. 1-(2-Deoxy-beta-D-ribofuranosyl)-2,4-difluoro-5-iodobenzene (dRFIB), a stable, non-polar thymidine mimic nucleoside, was synthesized in 5 steps following a literature method, for radioiodination with [(124)I] iodide via isotope exchange in the presence of copper sulphate and ammonium sulphate in methanol-water. The radiolabelling procedure was optimized with respect to temperature, amount of dRFIB, amount of sodium hydroxide and reaction time, to produce radiochemical yields of up to 85% with a 1-h reaction at 140 degrees C. With routine I-124 production of 30 MBq/run, relatively high specific activities, approaching 100 MBq/mmol, can be expected. The activation energy for dRFIB radioiodination was calculated from temperature-time RCY data to be approximately 100 kJ/mol using no-carrier-added [(124)I]iodide.
authors.affiliation: PET Center, Radiopharmacy, Eberhard Karls Universität Tübingen, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Stahlschmidt
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Machulla
authors.forename: Gerald
authors.initials: G
authors.lastname: Reischl
authors.forename: Edward E
authors.initials: EE
authors.lastname: Knaus
authors.forename: Leonard I
authors.initials: LI
authors.lastname: Wiebe
mesh_terms: D049109:Cell Proliferation; D003853:Deoxyribonucleosides / Q000138:chemical synthesis / Q000737:chemistry*; D007457:Iodine Radioisotopes; D007553:Isotope Labeling / Q000379:methods*; D018716:Molecular Mimicry; D013936:Thymidine / Q000031:analogs & derivatives
chemical_list: C483745:1-(2-deoxyribofuranosyl)-2,4-difluoro-5-iodobenzene; D003853:Deoxyribonucleosides; D007457:Iodine Radioisotopes; D013936:Thymidine