Novel difluoromethyl-containing 1-((4-methoxy-3-(piperazin-1-yl)phenyl) sulfonyl)-1H-indole scaffold as potent 5-HT6R antagonists: Design, synthesis, biological evaluation, and early in vivo cognition-enhancing studies

Herein, a series of novel 1-((4-methoxy-3-(piperazin-1-yl)phenyl)sulfonyl)-1H-indole derivatives were designed and synthesized via hybridization strategy of idalopirdine and SB-271046. The optimal compound C14 (K-i = 0.085 nM), with difluoromethyl on C3 position on indole scaffold, increased the affinity for the 5-HT6R up to 10 -folds than idalopirdine (K-i = 0.83 nM). Additionally, C14 had good pharmacokinetic properties and in vitro metabolic properties. Finally, C14 could efficiently reverse the scopolamine induced emotional memory deficits in novel object recognition assay in rats. Thus, we propose C14 might be considered as a new cognition -enhancing agent and the further studies are now underway in our laboratory.