Competitive antagonists for ionotropic glutamate receptors (iGluRs) are highly valuable tool compounds for studying health and disease states in the central nervous system. However, only few subtype selective tool compounds are available and the discovery of antagonists with novel iGluR subtype selectivity profiles remains a profound challenge. In this paper, we report an elaborate structure-activity relationship (SAR) study of the parental scaffold 2,3-trans-3-carboxy-3-phenyl-proline by the synthesis of 40 new analogues. Three synthetic strategies were employed with two new strategies of which one being a highly efficient and fully enantioselective strategy based on C(sp3)-H activation methodology. The SAR study led to the conclusion that selectivity for the NMDA receptors was a general trend when adding substituents in the 5'-position. Selective NMDA receptor antagonists were obtained with high potency (IC50 values as low as 200 nM) and 3-34-fold preference for GluN1/GluN2A over GluN1/GluN2B-D NMDA receptors.

中文翻译：

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立体选择性合成新的（2S，3R）-3-羧苯基）吡咯烷-2-羧酸类似物，在离子型谷氨酸受体上利用C（sp3）-H活化策略和结构-活性关系研究。

离子型谷氨酸受体（iGluRs）的竞争性拮抗剂是研究中枢神经系统健康和疾病状态的极有价值的工具化合物。然而，只有很少的亚型选择性工具化合物可用，具有新型iGluR亚型选择性特征的拮抗剂的发现仍然是一个严峻的挑战。在本文中，我们报告了通过合成40个新类似物对亲本支架2,3-trans-3-羧基-3-苯基-脯氨酸进行的详尽的构效关系（SAR）研究。使用了三种合成策略，其中两种是新的策略，其中一种是基于C（sp3）-H激活方法的高效且完全对映选择性的策略。SAR研究得出的结论是，在5'-位添加取代基时，对NMDA受体的选择性是普遍趋势。