R(-)-METHADONE HYDROCHLORIDE OPIOID AGON IST

Definition

ChEBI: Levomethadone is a 6-(dimethylamino)-4,4-diphenylheptan-3-one that has (R)-configuration. It is the active enantiomer of methadone and its hydrochloride salt is used to treat adults who are addicted to drugs such as heroin and morphine. It has a role as an antitussive, an opioid analgesic, a mu-opioid receptor agonist and a NMDA receptor antagonist. It is an enantiomer of a dextromethadone.

Purification Methods

This pharmacologically active (against narcotic addiction) enantiomer was obtained by optical resolution (using D-tartaric acid) of the racemate and was purified by precipitation of the hydrochloride from aqueous solution at pH >6, dried and recrystallised from propan-2-ol. The R-hydrochloride [5967-73-7], when recrystallised from propan-2-ol, has m 245-246o, [] D 20 -169o (c 2, EtOH). The S-(+)-enantiomer [5653-8-5] also recrystallises from propan-2-ol and has recorded m of 100-101o, [] D 25 + 26o (c 1.2, H2O). The S-hydrochloride [15284-15-8], when crystallised from propan-2-ol, has m 243-244o, [] D 20 +169o (c 2, EtOH). [Larsen et al. J Am Chem Soc 70 4194 1948, Brode & Hill J Org Chem 13 191 1948, Schultz et al. J Am Chem Soc 69 2454 1947, Easton et al. J Am Chem Soc 69 2941 1947, Winter & Flataker J Pharmacol Exp Ther 98 305 1950, Beilstein 14 III 278, 1 4 III/IV 300.]