Positive allosteric modulator of NMDA receptors. Potentiates NMDA receptors containing GluN2A, 2B, 2C and 2D subunits (EC50 values are 0.74, 3.07, 0.47 and 0.32 μM in a Ca2+ influx assay, respectively). Binds within the transmembrane domain and displays preference for agonist-bound NMDA receptors. Slows receptor deactivation and enhances the potency of glutamate and glycine. Purity 98%. MW (observed): 429.54