Novel aryloxyethyl derivatives of 1-(1-benzoylpiperidin-4-yl)methanamine as the Extracellular Regulated Kinases 1/2 (ERK1/2) phosphorylation-preferring serotonin 5 HT1A receptor biased agonists with robust antidepressant-like activity.

Novel 1-(1-benzoylpiperidin-4-yl)methanamine derivatives were designed as 'biased agonists' of serotonin 5-HT1A receptors. Compounds were tested in signal transduction assays (ERK1/2 phosphorylation, cAMP inhibition, Ca2+ mobilization and β-arrestin recruitment) which identified ERK1/2 phosphorylation-preferring aryloxyethyl derivatives. The novel series showed high 5 HT1A receptor affinity, >1000-fold selectivity versus noradrenergic α1, dopamine D2, 5-HT2A, histamine H1 and muscarinic M1 receptors, and favorable drug-likeness properties (CNS-MPO, Fsp3, LELP). The lead structure, (3-chloro-4-fluorophenyl)(4-fluoro-4-(((2-(pyridin-2-yloxy)ethyl)amino)methyl)piperidin-1-yl)methanone (17, NLX-204), displayed high selectivity in the SafetyScreen44™ panel (including hERG channel), high solubility, metabolic stability and Caco-2 penetration, and did not block CYP3A4, CYP2D6 isoenzymes or P-glycoprotein. Preliminary in vivo studies confirmed its promising pharmacokinetic profile. 17 also robustly stimulated ERK1/2 phosphorylation in rat cortex and showed highly potent (MED=0.16 mg/kg) and efficacious antidepressant-like activity, totally eliminating immobility in the rat Porsolt test. These data suggest that the present 5-HT1A receptor biased agonists could constitute promising antidepressant drug candidates.