Pentanthrene type heterocyclic compounds, which contain oxazole, isoxazole, oxadiazole, thiazole, isothiazole, thiadiazole or pyrrole ring as C-ring, and naphthalene, quinoline, isoquinoline or quinoxaline ring as A·B-ring, were prepared, and their monoamine oxidase (MAO) inhibitory activities were examined. As expected from our previous investigation on the structure-activity relationship of this series, most of them showed strong inhibitory potency to both MAO-A and MAO-B. However, a few indicated highly selective inhibition for either of MAO subtypes.
