Novel, Selective, and Developable Dopamine D₃ Antagonists with a Modified "Amino" Region

This Minireview describes a presentation made at the XXIV National Meeting in Medicinal Chemistry (NMMC) held in Perugia (Italy), September 11-14, 2016. It relates to the discovery of novel templates of the so-called "amino" region of dopamine D₃ receptor antagonists. Moving from the early scaffolds, which were modified in the amine portion, this review discusses the variations that led to the discovery of new systems published in 2016, which allowed the identification of compounds endowed with great selectivity over the dopamine D₂ receptor and the human ether-à-go-go-related gene (hERG) ion channel. The main efforts in characterizing these compounds were devoted not only to determining their potency and selectivity relative to closely associated targets (e.g., the dopamine D₂ receptor), but to ensure a large therapeutic window versus liability points such as hERG. In particular, we present examples of derivatives with selectivities greater than 2000-fold. Furthermore, much focus is devoted to the overall developability of the scaffolds, ensuring that appropriate physicochemical and pharmacokinetic parameters are present in all compounds progressing through the screening cascade.