Design and Synthesis of 7-hydroxy-2-(2-phenylethyl)chromones as Non-Nitrogenous 5-HT2 Receptor Ligands

Abstract

7-hydroxy-2-(2-phenylethyl)chromones are a class of non-amine, natural products that have demonstrated a broad range of pharmacological activities such as antiinflammatory activity. Following previous research conducted on 5-HPEC, 7-HPEC appears to be an attractive potential ligand candidate for serotonin 2 receptors (5-HT2). Studies have shown that 7-HPEC displayed similar inhibition towards all three 5-HT2 receptors. However, the transfer of the hydroxyl group on the phenyl ethyl substituent seemed to have significant effects on the binding of 7-HPEC ligand to the 5-HT2 receptors. In the present study, 7-HPEC analogues were synthesized to later investigate the structural activity relationships for this class of compounds. All starting material, including sixteen esters, was synthesized to give high yields, with the exception of one ester. Twenty-seven 7-HPEC analogues were synthesized via Claisen condensation followed by the acid-catalyzed cyclization of the condensation to give a wide range of percent yields. In regards to the yields, there were observed trends that can be explained by the purification method and solvents used for the trituration. Once purified, twentyfive of the compounds were sent to a Psychoactive Drug Screening program to be tested for inhibition on 5-HT2 receptors. Future studies will be to analyze the inhibition data to provide further insight as to how this natural class of compounds can be used to target various diseases.