The present invention relates to compounds of formula (I) wherein A is an unsubstituted cyclic group; and R is hydrogen or lower alkyl; and pharmaceutically acceptable acid addition salts thereof. It has been shown that the compounds of formulas IA and IB are good NMDA NR-2B receptor subtype specific blockers. Possible therapeutic indications for these compounds include acute forms of neurodegeneration caused, e.g., by stroke and brain trauma, and chronic forms of neurodegeneration such as Alzheimer's disease, Parkinson's disease, Huntington's disease, ALS(amyotrophic lateral sclerosis) and neurodegeneration associated with bacterial or viral infections and, in addition, depression and chronic and acute pain.