A comprehensive description of GluN2B-selective N-methyl-D-aspartate (NMDA) receptor antagonists

l-glutamate is an excitatory neurotransmitter in the central nervous system (CNS), which can activate ionotropic receptors (iGluRs) and metabotropic (mGluRs) receptors. N-methyl-D-aspartate (NMDA) receptor is a ligand-gated ion channel belonging to the iGluRs family. Among NMDA receptor subtypes, GluN2B subtype plays a crucial role in CNS diseases. In this review, we summarize, classify and discuss the reports on GluN2B antagonists, published from the 1990s to 2020, to provide the therapeutic potential of GluN2B antagonists on various disorders. The GluN2B antagonists are broadly classified into two categories, which are prototypical antagonists and atypical antagonists. And the latter are further divided into amidine derivatives, 4-aminoquinolines, indole derivatives, benzimidazole derivatives, oxamide derivatives, carbamate derivatives, EVT-101 analogues, 1H-pyrrolo[3,2-b]pyridine derivatives, benzazepin derivatives, other heterocyles and radiotracers. This review will provide a comprehensive description including structure, structure-activity relationship (SAR), and pharmacology of novel GluN2B-subtype selective NMDA antagonists to the medicinal chemists, which would be helpful in rational designing effective drugs aimed toward related CNS disease.