A-Methadol

The relative binding affinities of the optical isomers of methadone, a-methadol, a-acetylmethadol and their N-demethylated derivatives to the opiate receptors of rat brain confirmed the agonistic nature of this series of drugs.144... 

When the ketone on carbon 5 of methadone is reduced to an alcohol, a second asymmetric carbon is developed (92). The four optically active isomers are known as (1) d-a-methadol, (2) d-/3-methadol, (3) Z-a-meth-adol, and (4) Z-(3-methadol. 

These compounds were recently developed (1952) and their pharmacology is incomplete. Reduction of d-methadone yields an a-methadol which is levorotatory. Acetyl-a-methadol is also levorotatory. Z-a-Meth-adol designates the levorotatory alcohol derived from d-methadone, and d-a-methadol the dextrorotatory alcohol derived from Z-methadone (92). Z-/3-Methadol designates the levorotatory alcohol from Z-methadone and d- -methadol the dextrorotatory alcohol from d-methadone. 

The a- and /3- racemic dZ-methadols are less effective than dZ-methadone the acetyl esters have toxicities similar to the parent compound, but produce more pronounced analgesia than does dZ-methadone (7). d-a-Afethadol and Z- -methadol were less effective than the parent compound Z-methadone. However, Z-a-methadol, Z-a-acetylmethadol, and d-/3 ac-etylmethadol exhibited analgesic activity when administered orally or subcutaneously these compounds are derived from d-methadone which has only slight analgesic activity (7). 

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