Referenced in: none

Automatically associated channels: Kir2.3

Title: Studies on an (S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor antagonist IKM-159: asymmetric synthesis, neuroactivity, and structural characterization.

Authors: Lina Juknaitė, Yutaro Sugamata, Kazuya Tokiwa, Yuichi Ishikawa, Satoshi Takamizawa, Andrew Eng, Ryuichi Sakai, Darryl S Pickering, Karla Frydenvang, Geoffrey T Swanson, Jette S Kastrup, Masato Oikawa

Journal, date & volume: J. Med. Chem., 2013 Mar 28 , 56, 2283-93

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/23432124

Abstract
IKM-159 was developed and identified as a member of a new class of heterotricyclic glutamate analogues that act as AMPA receptor-selective antagonists. However, it was not known which enantiomer of IKM-159 was responsible for its pharmacological activities. Here, we report in vivo and in vitro neuronal activities of both enantiomers of IKM-159 prepared by enantioselective asymmetric synthesis. By employment of (R)-2-amino-2-(4-methoxyphenyl)ethanol as a chiral auxiliary, (2R)-IKM-159 and the (2S)-counterpart were successfully synthesized in 0.70% and 1.5% yields, respectively, over a total of 18 steps. Both behavioral and electrophysiological assays showed that the biological activity observed for the racemic mixture was reproduced only with (2R)-IKM-159, whereas the (2S)-counterpart was inactive in both assays. Racemic IKM-159 was crystallized with the ligand-binding domain of GluA2, and the structure revealed a complex containing (2R)-IKM-159 at the glutamate binding site. (2R)-IKM-159 locks the GluA2 in an open form, consistent with a pharmacological action as competitive antagonist of AMPA receptors.