RESUMO
Several indole derivatives and analogues comprising a range of related structural classes were designed, synthesized and tested as ligands for the 5-HT4 receptor. Within each series, binding experiments showed compounds with good affinity demonstrating high percentage displacement values at 1 µM. The most potent of these (20) had a pKi of 8.54 demonstrating very good affinity. These indole analogues were combined with 55 ligands that were previously produced in our laboratory to explore the structure-activity relationships of these 5-HT4 ligands. A CoMFA (Comparative Molecular Field Analysis) analysis was used to extend an earlier simple pharmacophore to suggest two new molecular features beyond the primary amino binding site. The pharmacophore confirmed that a newly described tetrahydroquinoline analogue was able to match the basic requirements of the model and the pharmacology of this molecule is provided in more detail.
Assuntos
Receptores 5-HT4 de Serotonina/química , Sítios de Ligação , Cinética , Ligantes , Relação Estrutura-AtividadeRESUMO
Twenty-three indole-3-methanamines were designed, synthesized and evaluated as ligands for the 5-HT(4) receptor. Compounds I-d, I-j, I-o, I-q and I-u showed good affinity at 100 microM and I-o was found to be only 5-fold less potent than the agonists serotonin (1) and 5-methoxytryptamine (2). Substitution on the 3-methanamine nitrogen clearly influenced activity with docking experiments into a homology model of the 5-HT(4) receptor showing a range of interactions with these side chain substituents. This modelling work together with the SAR determined in this study has provided promising ideas for future synthetic work.