Preparation of 11C-labelled Raclopride, a new potent dopamine receptor antagonist: preliminary PET studies of cerebral dopamine receptors in the monkey.
A new dopamine receptor antagonist, Raclopride (S-(-)-3,5-dichloro-N-[(1-ethyl-2-pyrrolidinyl)]methyl-2-hydroxy- 6-methoxybenzamide, FLA 870) (1), has been labelled using [11C]ethyl iodide for alkylation of the nitrogen of the pyrrolidine ring in the corresponding secondary amine (5). The synthesis of 5 and an efficient method for the preparation of [11C]ethyl iodide are described. The 11C-labelled FLA 870 (1) was purified by HPLC and then used in positron emission tomography to visualize the dopamine receptor-rich areas of the monkey brain. The images obtained show selective accumulation of FLA 870 in striatum and a 10-fold separation between the binding to caudate vs cerebellum.
D000818:Animals; D001549:Benzamides; D001921:Brain / Q000000981:diagnostic imaging*; D002250:Carbon Radioisotopes; D007553:Isotope Labeling / Q000379:methods; D008252:Macaca fascicularis; D020891:Raclopride; D011954:Receptors, Dopamine / Q000032:analysis*; D014055:Tomography, Emission-Computed
D001549:Benzamides; D002250:Carbon Radioisotopes; D011954:Receptors, Dopamine; D020891:Raclopride