Esmethadone
Esmethadone, also known as dextromethadone, is the -enantiomer of methadone. It acts as an N-methyl-D-aspartate receptor NMDA [receptor antagonist|antagonist], among other actions. Unlike levomethadone, it has low affinity for opioid receptors and lacks significant respiratory depressant action and abuse liability.
Esmethadone has been under development for major [depressive disorder].
There is an asymmetric synthesis available to prepare both esmethadone and levomethadone.