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.
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.
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CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL GENE-Y GENE-N GENE-N GENE-Y GENE-N CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL
(2R)-IKM-159 (2R)-IKM-159 IKM-159 (S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid AMPA GluA2 AMPA receptors AMPA receptor GluA2 (AMPA) receptor IKM-159 AMPA IKM-159 IKM-159 (R)-2-amino-2-(4-methoxyphenyl)ethanol (2R)-IKM-159 (2R)-IKM-159 Racemic IKM-159 glutamate