Analogues of naltrindole and N1′-methylnaltrindole having radioiodine in the 7′-position of the indole ring have been prepared for evaluation as delta opioid receptor ligands. The no-carrier-added radiosyntheses were conducted by Cu(I) assisted nucleophilic exchange of radioiodide for bromide under reducing conditions at 190 °C. A combination of HPLC and solid-phase extraction gave the 125I- or 123I-labeled products in satisfactory yields (47%) with high radiochemical purities (>98%) and high specific activities (125I: 43-68 GBq/μmol, 1155-1833 mCi/μmol; 123I: >92GBq/μmol, 2500mCi/μmol).
ASJC Scopus subject areas
- Molecular Medicine
- Radiology Nuclear Medicine and imaging
- Cancer Research