The invention related to compounds of the general formula (I), wherein the substituents are defined in claim 1. These compounds have a good affinity to the NMDA (N-methyl-D-aspartate)-receptor subtype selective blockers, which have a key function in modulating neuronal activity and plasticity which makes them key players in mediating processes underlying development of CNS as well as learning and memory formation. These compounds are therefore suitable in the control or treatment of diseases, related to this receptor.