A Search for New 5-HT1A/5-HT2A Receptor Ligands. In Vitro and in vivo Studies of 1-[ω-(4-Aryl-1-piperazinyl)alkyl]indolin-2(1H)-ones

A series of 1-[ω-(4-aryl-1-piperazinyl)alkyl]indolin-2(1H)-one derivatives 2–14 was synthesized in order to obtain ligands with a dual 5-HT_1A/5-HT_2A activity. The majority of those compounds ( 2–5, 7, 10–13 ) exhibited a high 5-HT_1A (K_i = 2 – 44 nM) and/or 5-HT_2A affinity (K_i = 51 and 39 for 5 and 7 , respectively). Induction of lower lip retraction (LLR) and behavioral syndrome and inhibition of these efects evoked by 8-hydroxy-2-(di-n-propyl-amino)tetralin (8-OH-DPAT) were used for determination the agonistic and antagonistic activity, respectively, at 5-HT_1A receptors. The 5-HT_2A antagonistic activity was assessed by the blocking effect on the head twitches induced by (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) in mice. Two of the tested compounds, 1-{3-[4-(3-chlorophenyl)-1-piperazinyl]propyl}-6-fluoroindolin-2(1H)-one ( 5 ) and 1-{3-[4-(2-methoxyphenyl)-1-piperazinyl]propyl}indolin-2(1H)-one ( 7 ), demonstrated a high 5-HT_1A/5-HT_2A affinity and an in vivo antagonistic activity towards both receptor subtypes.