HTR6 and memory impairment: In fact, it is difficult to find either agonist or antagonist for 5-HT6R which reversed memory impairments in the NOR test in doses lower than 1 mg/kg at i.p. administration, while the 2,3-dichlorophenyl derivative (2) showed such effects at 0.3 mg/kg, and the unsubstituted phenyl derivative (3) even at 0.1 mg/kg i.p. The beneficial effect of 5-HT6 receptors ligands on memory functions has been repeatedly reported in literature.