A series of conformationally-flexible analogues was prepared and their affinities for D2-like dopamine (D2, D3 and D4) were determined using in vitro radioligand binding assays. The results of this structure–activity relationship study identified one compound, 15, that bound with high affinity (Ki value= 2nM) and moderate selectivity (30-fold) for D3 compared to D2 receptors. In addition, this series of compounds were also tested for affinity at σ1 and σ2 ...
