Abstract:

The structure-affinity correlations of a series of benzamides for dopamine D 2 receptor imaging agents have been studied with SYBYL 6.4 software on SGI O 2 workstation. The results of conformational analysis and PM3 calculation have demonstrated that the coplanar effect of benzamides is one of the most important requirements for activity in vitro. The aromatic substituent in the 2 position is the main factor which influences the coplanar arrangement of pseudring (B) involving the amide moiety and the methoxy group relative to the aromatic ring, while the influences of other factors on this side such as the aromatic substituents in the 3 and 5 positions and the conformation of side chain may be neglected. The conclusion may be useful in understanding the interaction of D 2 receptor-ligand and designing new D2 receptor ligands.

Key words: Benzamides, Dopamine D₂ receptor imaging agents, Coplanar effect