Design, synthesis and biological evaluation of novel bicyclo[1.1.1]pentane-basedx-acidic amino acids as glutamate receptors ligands

A novel series of bicyclo[1.1.1]pentane-based x-acidic amino acids, including (2S)- and (2R)-3-(30-carboxybicyclo[ 1.1.1]pentyl)alanines (8 and 9), (2S)- and (2R)-2-(30-carboxymethylbicyclo[1.1.1]pentyl)glycines (10 and 11), and (2S)- and (2R)-3-(30-phosphonomethylbicyclo[1.1.1]pentyl)glycines (12 and 13), were synthesized and evaluated as glutamate receptor ligands. Among them, (2R)-3-(30-phosphonomethylbicyclo[ 1.1.1]pentyl)glycine (13) showed relatively high affinity and selectivity at the NMDA receptor. The results are also discussed in light of pharmacophoric modelling studies of NMDA agonists and antagonists.