Design, synthesis and structure-activity relationships of novel strychnine-insensitive glycine receptor ligands

The in vitro activities of 3-hydroxy-imidazolidin-4-one derivatives demonstrated very restricted structure-activity relationships at the strychnine-insensitive glycine site of the NMDA receptor. The most active compound (3a) was completely unsubstituted and exhibited affinity and efficacy similar to that of D-cycloserine, the prototypical partial agonist at this site.