Aporphines. 58. N-(2-Chloroethyl)norapomorphine, an Irreversible Ligand for Dopamine Receptors: Synthesis and Application

Article abstract of DOI:10.1021/jm00372a019

The synthesis of the title compounds (1c and its 2H isomer 1b) from N-(2-hydroxyethyl)norapomorphine was carried out by ring bromination, followed by chlorination to the 2-chloroethyl compound 6.Further reduction with 2H2 or 3H2 and Pd/C gave 1b or 1c.Radiochemically pure (97percent) 1c was obtained with a specific activity of 16.3 Ci/mmol.The purity of 1c was determined by LC, HPLC, UV, and NMR. <3H>NCA was shown to label the D₂ receptor; however, the D₂ signal appears to be only a small portion of the total signal, which may include binding to other dopamine receptor subtypes (D₁ and D₃).