(4-Benzylpiperidine-1-yl)-(6-hydroxy-1 H-indole-2-yl)-methanone (6a) derived from (E)-1-(4- benzylpiperidin-1-yl)-3-(4-hydroxy-phenyl)-propenone (5) was identified as a potent NR2B subunit-selective antagonist of the NMDA receptor. To establish the structure-activity relationship (SAR) and to attempt the improvement of the ADME properties of the lead, a series of compounds were prepared and tested. Several derivatives showed low ...