Synthesis of radioiodinated naltrindole analogues: ligands for studies of delta opioid receptors.
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 degrees 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/mumol, 1155-1833 mCi/mumol; 123I: > 92 GBq/mumol, 2500 mCi/mumol).
Kinter
C M
CM
Department of Environmental Health Sciences, Johns Hopkins University School of Hygiene and Public Health, Baltimore, MD 21205-2179, USA.
Lever
J R
JR
D002851:Chromatography, High Pressure Liquid; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D008024:Ligands; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D009292:Narcotic Antagonists / Q000138:chemical synthesis*; D017465:Receptors, Opioid, delta / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D015899:Tomography, Emission-Computed, Single-Photon
D007457:Iodine Radioisotopes; D008024:Ligands; D009292:Narcotic Antagonists; D017465:Receptors, Opioid, delta; D009271:Naltrexone; C055382:naltrindole