D2 and D3 receptors is quite similar to that of 3a,(S)-(-)-3b being about 4 times more potent than ita enantiomer at both receptors.(R)-(+)-3b binds preferentially to u S1 over S2 sites, while (S)-(-)-3b displays the opposite selectivity profile. Both enantiomers of 3c possess very weak affinity for D2 and D3 receptors. In a manner similar to the enantiomers of 3b, the affinity of (R)-(+)-3c is greater for S1 than S2 sites, while (S)-(-)-3c displays the opposite ...
