Design and Synthesis of a Series of 6-Substituted-2-pyridinylmethylamine Derivatives as Novel, High-Affinity, Selective Agonists at 5-HT<sub>1A</sub> Receptors
作者:Bernard Vacher、Bernard Bonnaud、Philippe Funes、Nathalie Jubault、Wouter Koek、Marie-Bernadette Assié、Cristina Cosi
DOI:10.1021/jm9804329
日期:1998.12.1
A search for novel, selective agonists with high intrinsic activity at the 5-HT1A subtype of serotonin (5-HT) receptors was undertaken. Mechanistic and thermodynamic considerations led to the design of 6-substituted-2-pyridinylmethylamine as a potential 5-HT1A pharmacophore. Various adducts derived from the 6-substituted-2-pyridinylmethylamine moiety were tested for their affinity at 5-HT1A, alpha(1)-adrenergic, and D-2-dopaminergic receptors. Compounds with high affinity for 5-HT1A receptors (pK(i) greater than or equal to 8) were examined for agonist properties by measuring their ability to inhibit forskolin-stimulated cAMP production in HA7 cells (i.e., HeLa cells permanently transfected with the h5-HT1A receptor gene and expressing the h5-HT1A receptor protein). Several compounds of the type aryl4-[(6-substituted-pyridin-2-ylmethylamino)methyl]piperidin-1-yl}methanone had nanomolar affinity for 5-HT1A binding sites and were more than 500-fold selective with respect to alpha(1) and D-2 sites. Importantly, their 5-HT1A agonist properties were demonstrated in HA7 cells where they behaved as potent inhibitors of cAMP accumulation. In particular, (3,4-dichlorophenyl)4-[(6-oxazol-5-ylpyridin-2-ylmethylamino)methyl]piperidin-1-yl}methanone (70) and (3,4-dichlorophenyl)4-[(6-azetidinopyridin-2-ylmethylamino)methyl]piperidin-1-yl}methanone (36) appeared to be more potent than, and at least as efficacious as, the prototypical 5-HT1A agonist (+/-)-8-OH-DPAT. SAR studies revealed that the pyridine nitrogen atom and the nature and the position of the substituents on the pyridine ring were critically involved in the ability of the compounds to recognize and activate 5-HT1A receptors. Structural modifications of the nonpharmacophoric part of the molecule showed, however, that the entire structure was required for affinity at 5-HT1A binding sites.