SYNTHESIS OF THE SEROTONIN LIGANDS, RS-56532-C-14 AND RS-66331-C-14 FROM A COMMON LABELED INTERMEDIATE

Two approaches towards the synthesis of 3-chloro-4-amino-1,8-naphthali c anhydride-C-14!, which served as the common intermediate in the pre paration of the two title compounds, are described. Although nucleophi lic incorporation of the label via KCN was superior to an electrophili c sequence using CO2, the latter approach was adopted since the nitril e could not be hydrolyzed to the desired acid. The specific activities of RS-56532-C-14 and RS-66331-C-14 were 56.8 mCi/mmol and 53.7 mCi/mm ol, respectively.