Synthesis, pharmacological investigation and computational studies on a tricyclic ergoline analog with selective dopamine autoreceptor activity

The structural evolution of dopamine D3 receptor ligands: structure-activity relationships and selected neuropharmacological aspects

"Evolution consists largely of molecular tinkering."-Following the famous concept of the molecular geneticist and medicine Nobel laureate François Jacob, in this review we describe the structural evolution of dopamine D3 receptor ligands from the natural agonist dopamine (DA) to highly potent and subtype selective new agents by bioisosteric tinkering with well-established and privileged or novel and fancy chemical functionalities and scaffolds. Some of the more than 200 ligands presented herein have already achieved therapeutic or scientific value up to now, some will most likely achieve it in the future. Hence, great importance is not only attached to the relationship between structure and activity of the ligands, but also to their utility as pharmacological tools in animal models or as therapeutics in patients with neurological diseases or other disorders.

Synthesis and dopamine receptor binding studies of homochiral 8-aminopyrido[1,2-a]indoles

Starting from L-aspartic acid the preparation of 8-aminopyrido[1,2-a]indole derivatives as benzo-fused analogs of the dopamine autoreceptor agonist 1 is reported. The key step of the synthesis is the Tf2O induced cyclization of the 1,2-amino alcohol 6. Receptor binding studies indicated selective affinity for the D-2 autoreceptor. Among the tested compounds, the dipropylamino derivative 2 showed the highest affinity for the D-2 receptor labelled with the selective autoreceptor agonist pramipexole (IC50 value: 450 nM). Thus, 2 is 15 times less potent than the aminoindolizine 1.