Compounds having NR2B selective NMDA receptor antagonist activity are disclosed of the formula (I) ##STR00001## wherein one of the neighboring R.sup.1, R.sup.2, R.sup.3 and R.sup.4 groups is hydroxy, and the others are each hydrogen atoms, R.sup.5 and R.sup.6 together with the nitrogen between them form a saturated or unsaturated, 4-6 membered heterocyclic ring, which is substituted by phenoxy, phenyl-(C.sub.1-C.sub.4 alkyl), phenyl-(C.sub.1-C.sub.4 alkoxy), phenoxy-(C.sub.1-C.sub.4 alkyl), or benzoyl, optionally substituted on the aromatic ring by one or more halogen atoms, cyano or hydroxy groups, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 alkoxy groups, X is NH--, Y is a nitrogen atom, or pharmaceutically acceptable salts thereof formed with acids or bases.