A novel (benzodifuranyl)aminoalkane compound was synthesized and evaluated for activity at the 5-HT2A receptor. The compound exhibited extremely potent activity, with a Ki value of 0.4 nM at the human 5-HT2A receptor, making it one of the most potent 5-HT2A receptor agonists reported. It also showed high selectivity over other serotonin receptor subtypes. In rodent behavioral assays, the compound produced effects consistent with 5-HT2A receptor activation, including the head-twitch response in mice. These findings suggest the compound is a valuable tool for studying 5-HT2A receptor function and may have implications for developing new therapeutic agents.
Two thienopyrrole compounds, designed as structural replacements for the indole ring in N,N-dimethyltryptamine (DMT), were synthesized and tested. Neither compound produced LSD-like effects in rats trained to discriminate LSD or DOI, even at high doses. However, both fully substituted for a 5-HT1A receptor agonist and caused behaviors consistent with 5-HT1A activation, such as serotonin syndrome and salivation. At the 5-HT2A receptor, one compound had twice the affinity of the other, while at 5-HT2B and 5-HT2C receptors the pattern reversed. The thienopyrrole replacement thus failed to mimic DMT's activity at 5-HT2 receptors but enhanced activity at the 5-HT1A receptor, indicating that serotonin receptor subtypes respond differently to subtle electronic changes in the aromatic ring system.