Methoxy-substituted 9-aminomethyl-9,10-dihydroanthracene (AMDA) derivatives exhibit differential binding affinities at the 5-HT2A receptor

The effects of methoxy-substitution at the 1-, 2-, 3-, and 4-positions of 9-aminomethyl-9,10-dihydroanthracene (AMDA) on h5-HT2A receptor affinity were determined. Racemic mixtures of these compounds were found to show the following affinity trend: 3-MeO > 4-MeO > 1-MeO not, vert, similar 2-MeO. Comparison of the effects of these substitutions, with the aid of computational molecular modeling techniques, suggest that the various positional and stereochemical isomers of the methoxy-substituted AMDA compounds interact differently with the h5-HT2A receptor. It is predicted that for the compounds with higher affinities, the methoxy oxygen atom is able to interact with hydrogen bond-donating sidechains within alternative h5-HT2A receptor binding sites, whereas the lower-affinity isomers lack this ability.