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Levopropoxyphene is an
#
antitussive
Cold medicines are a group of medications taken individually or in combination as a treatment for the symptoms of the common cold and similar conditions of the upper respiratory tract. The term encompasses a broad array of drugs, including ...
. It is an optical isomer
In chemistry, a molecule or ion is called chiral () if it cannot be superposed on its mirror image by any combination of rotations, translations, and some conformational changes. This geometric property is called chirality (). The terms are d ...
of dextropropoxyphene
Dextropropoxyphene is an analgesic in the opioid category, patented in 1955 and manufactured by Eli Lilly and Company. It is an optical isomer of levopropoxyphene. It is intended to treat mild pain and also has antitussive (cough suppressant) ...
. The racemic mixture
In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. ...
is called propoxyphene
Dextropropoxyphene is an analgesic in the opioid category, patented in 1955 and manufactured by Eli Lilly and Company. It is an optical isomer of levopropoxyphene. It is intended to treat mild pain and also has antitussive (cough suppressant) a ...
. Only the dextro-isomer (dextropropoxyphene) has an analgesic effect; the levo-isomer appears to exert only an antitussive effect. It was formerly marketed in the U.S. by Eli Lilly under the tradename Novrad (a reversal of Darvon
Dextropropoxyphene is an analgesic in the opioid category, patented in 1955 and manufactured by Eli Lilly and Company. It is an optical isomer of levopropoxyphene. It is intended to treat mild pain and also has antitussive (cough suppressant) a ...
) as an antitussive. Unlike many antitussives, it binds poorly to the sigma-1 receptor
The sigma-1 receptor (σ1R), one of two sigma receptor subtypes, is a chaperone protein at the endoplasmic reticulum (ER) that modulates calcium signaling through the IP3 receptor. In humans, the σ1 receptor is encoded by the ''SIGMAR1'' gene. ...
.
Synthesis
#Mannich reaction
In organic chemistry, the Mannich reaction is a three-component organic reaction that involves the amino alkylation of an acidic proton next to a carbonyl () functional group by formaldehyde () and a primary or secondary amine () or ammonia (). ...
of propiophenone
Propiophenone (shorthand: benzoylethane or BzEt) is an aryl ketone. It is a colorless, sweet-smelling liquid that is insoluble in water, but miscible with organic solvents. It is used in the preparation of other compounds.
Production
Propiopheno ...
with formaldehyde
Formaldehyde ( , ) (systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section F ...
and dimethylamine
Dimethylamine is an organic compound with the formula (CH3)2NH. This secondary amine is a colorless, flammable gas with an ammonia-like odor. Dimethylamine is commonly encountered commercially as a solution in water at concentrations up to aroun ...
affords the corresponding aminoketone.
#Reaction of the ketone with benzylmagnesium bromide gives the amino alcohol. It is of note that this intermediate fails to show analgesic activity in animal assays.
#Esterification of the alcohol by means of propionic anhydride affords the propionate.
Chirality
The presence of two chiral centers in this molecule means that the compound can exist as any of four isomers. The biologic activity has been found to be associated with the α-isomer. Resolution of that isomer into its optical antipodes showed the d isomer to be the active analgesic; this is now denoted as propoxyphene. The l isomer is almost devoid of analgesic activity; the compound does, however, show usefulantitussive
Cold medicines are a group of medications taken individually or in combination as a treatment for the symptoms of the common cold and similar conditions of the upper respiratory tract. The term encompasses a broad array of drugs, including ...
activity and is named levopropoxyphene.
References
{{reflist Synthetic opioids Antitussives Propionate esters