Discovery of Trace Amine Associated Receptor 1 (TAAR1) Agonist 2-(5-(4'-Chloro-[1,1'-biphenyl]-4-yl)-4H-1,2,4-triazol-3-yl)ethan-1-amine (LK00764) for the Treatment of Psychotic Disorders.

A focused in-house library of about 1000 compounds comprising various heterocyclic motifs in combination with structural fragments similar to β-phenethylamine (PEA) or tyramine was screened for the agonistic activity towards trace amine-associated receptor 1 (TAAR1). The screening yielded two closely related hits displaying EC50 values in the upper submicromolar range. Extensive analog synthesis and testing for TAAR1 agonism in a BRET-based cellular assay identified compound 62 (LK00764) with EC(50) = 4.0 nM. The compound demonstrated notable efficacy in such schizophrenia-related in vivo tests as MK-801-induced hyperactivity and spontaneous activity in rats, locomotor hyperactivity of dopamine transporter knockout (DAT-KO) rats, and stress-induced hyperthermia (i.p. administration). Further preclinical studies are necessary to evaluate efficacy, safety and tolerability of this potent TAAR1 agonist for the potential development of this compound as a new pharmacotherapy option for schizophrenia and other psychiatric disorders.