In this work, a novel structural series of brain-penetrant GluN2B NMDAR antagonists were designed, synthesized and biologically evaluated as anti-stroke therapeutic agents via merging the structures of NBP and known GluN2B ligands. Approximately half of them exhibited superior neuroprotective activity to NBP against NMDA-induced neurotoxicity in hippocampal neurons at 10 μM, and compound 45e and 45f exerted equipotent activity to ifenprodil, an approved GluN2B- selective NMDAR antagonist. In particular, 45e, with the most potent neuroprotective activity throughout this series, displayed dramatically enhanced activity (K_i = 3.26 nM) compared to ifenprodil (K_i = 14.80 nM) in Radioligand Competitive Binding Assay, and remarkable inhibition (IC₅₀ = 79.32 nM) against GluN1/GluN2B receptor-mediated current in Patch Clamp Assay. Meanwhile, 45e and its enantiomers exhibited low inhibition rate against the current mediated by other investigated receptors at the concentration of 10 μM, indicating their favorable selectivity for GluN1/GluN2B. In the rat model of middle cerebral artery ischemia (MCAO), 45e exerted comparable therapeutic efficacy to ifenprodil at the same dosage. In addition to the attractive in vitro and in vivo potency, 45e displayed a favorable bioavailability (F = 63.37%) and an excellent brain exposure. In further repeated dose toxicity experiments, compound 45e demonstrated an acceptable safety profile. With the above merits, 45e is worthy of further functional investigation as a novel anti-stroke therapeutic agent.

在这项工作中，通过合并 NBP 和已知 GluN2B 配体的结构，设计、合成和生物学评估了一系列新的脑穿透性 GluN2B NMDAR 拮抗剂结构作为抗中风治疗剂。其中大约一半在 10 μM 时对 NBP 对海马神经元中 NMDA 诱导的神经毒性表现出优异的神经保护活性，并且化合物 45e 和 45f 对艾芬地尔（一种已批准的 GluN2B 选择性 NMDAR 拮抗剂）具有同等活性。特别是，在整个系列中具有最有效的神经保护活性的 45e在放射配体竞争结合试验中与艾芬地尔 (K _i  = 14.80 nM  ) 相比，显示出显着增强的活性 (K _{i = 3.26 nM)，并具有显着的抑制作用 (IC 50} = 79.32 nM) 在膜片钳检测中针对 GluN1/GluN2B 受体介导的电流。同时，45e及其对映体在10 μM浓度下对其他研究受体介导的电流表现出较低的抑制率，表明它们对GluN1/GluN2B具有良好的选择性。在大脑中动脉缺血（MCAO）大鼠模型中，45e在相同剂量下表现出与艾芬地尔相当的疗效。除了有吸引力的体外和体内效力时，45e 显示出良好的生物利用度 (F = 63.37%) 和出色的大脑暴露。在进一步的重复剂量毒性实验中，化合物 45e 表现出可接受的安全性。具有上述优点，45e作为一种新型抗中风治疗剂值得进一步研究。