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 (97%) 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).