5-Cyclic Amine-3-arylsulfonylindazoles as Novel 5-HT₆Receptor Antagonists

Novel 5-cyclic amine-3-arylsulfonylindazoles were prepared, and several analogues within this class have been identified as high-affinity 5-HT6 receptor ligands with improved pharmacokinetic and pharmacological properties. One selected example, 18b, showed good brain penetrability and a generally favorable pharmacokinetic profile with procognitive efficacy in the rat novel object recognition assay. The synthesis and structure activity relationship of this potent class are discussed.