The present invention is directed to radiolabeled neuropeptide Y Y5 receptor antagonists of the formula: (see above formula) which can be labeled with a radionuclide selected from the group consisting of: 3H, 11C, 18F, 15O and 13 N; analogs of this compound could be labeled with 1251, 123I, 131I, 75Br, 15O, 13N, 211At, 82Br, 77Br or 76Br; particular antagonists include [11C] trans-N-[5-(2-fluorophenyl)-2-pyrimidinyl]-3-oxospiro[5-azaisobenzofurane-1(3H),1'-cyclohexane]-4'-carboxamide and [18F] trans-N-[5-(2-fluorophenyl)-2-pyrimidinyl]-3-oxospiro[5-azaisobenzofurane-1(3H),1'-cyclohexane]-4'-carboxamide and pharmaceutically acceptable salts thereof; the antagonists are useful for the labeling and diagnostic imaging of neuropeptide Y Y5 receptors in mammals.
RADIOLABELED NEUROPEPTIDE Y Y5 RECEPTOR ANTAGONISTS