Studies on 2(1H)-quinolinone derivatives as neuroleptic agents. I. Synthesis and biological activities of (4-phenyl-1-piperazinyl)-propoxy-2(1H)-quinolinone derivatives.

With the aim of developing a novel neuroleptic drug, a series of ω-(4-phenyl-1-piperazinyl)-alkoxy-2 (1H)-quinolinone derivatives have been synthesized and tested for anti-methamphetamine and anti-epinephrine activities. Most of the derivatives were found to possess a potent antimethamphetamine activity in the jumping behavior test on mice treated with 3-(3, 4-dihydroxyphenyl)-L-alanine (L-DOPA) and methamphetamine, or in the lethality test with methamphetamine-treated mice. They also showed relatively high anti-epinephrine potency depending on the nature or number of substituents on the phenyl group in the 4-phenyl-1-piperazinyl moiety; some of these compounds induced only weak catalepsy in mice. Among them, 7-{3-[4-(2, 3-dimethylphenyl)-1-piperazinyl]propoxy}-2 (1H)-quinolinone (OPC-4392), which was suggested to be a dopamine autoreceptor agonist, was selected for further investigations. The structure-activity relationships are also discussed.