Louisa Temme, Elena Bechthold, Julian A Schreiber, Sandeep Gawaskar, Dirk Schepmann, Dina Robaa, Wolfgang Sippl, Guiscard Seebohm, Bernhard Wünsch
European journal of medicinal chemistry 2020 Mar 15A set of GluN2B NMDA receptor antagonists with conformationally restricted phenylethylamine substructure was prepared and pharmacologically evaluated. The phenylethylamine substructure was embedded in ring expanded 3-benzazocines 4 as well as ring-contracted tetralinamines 6 and indanamines 7. The ligands 4, 6 and 7 were synthesized by reductive alkylation of secondary amine 11, reductive amination of ketones 12 and 16 and nucleophilic substitution of nosylates 14 and 17. The moderate GluN2B affinity of 3-benzazocine 4d (Ki = 32 nM) translated into moderate cytoprotective activity (IC50 = 890 nM) and moderate ion channel inhibition (60% at 10 μM) in two-electrode voltage clamp experiments with GluN1a/GluN2B expressing oocytes. Although some of the tetralinamines 6 and indanamines 7 showed very high GluN2B affinity (e.g. Ki (7f) = 3.2 nM), they could not inhibit glutamate/glycine inducted cytotoxicity. The low cytoprotective activity of 3-benzazocines 4, tetralinamines 6 and indanamines 7 was attributed to the missing OH moiety at the benzene ring and/or in benzylic position. Docking studies showed that the novel GluN2B ligands adopt similar binding poses as Ro 25-6981 with the central H-bond interaction between the protonated amino moiety of the ligands and the carbamoyl moiety of Gln110. However, due to the lack of a second H-bond forming group, the ligands can adopt two binding poses within the ifenprodil binding pocket. Copyright © 2020 Elsevier Masson SAS. All rights reserved.
Louisa Temme, Elena Bechthold, Julian A Schreiber, Sandeep Gawaskar, Dirk Schepmann, Dina Robaa, Wolfgang Sippl, Guiscard Seebohm, Bernhard Wünsch. Negative allosteric modulators of the GluN2B NMDA receptor with phenylethylamine structure embedded in ring-expanded and ring-contracted scaffolds. European journal of medicinal chemistry. 2020 Mar 15;190:112138
PMID: 32070917
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