Levopropoxyphene

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Levopropoxyphene
Levopropoxyphene.png
Identifiers
CAS number 2338-37-6 N
PubChem 200742
ChemSpider 21234163 N
ChEMBL CHEMBL1213351 N
Jmol-3D images Image 1
Image 3
Properties
Molecular formula C22H29NO2
Molar mass 339.47 g mol−1
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Levopropoxyphene is an antitussive. It is an optical isomer of dextropropoxyphene. The racemic mixture is called propoxyphene. 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 as an antitussive.[1][2]

Synthesis[edit]

Propoxyphene synthesis[3]
  1. Mannich reaction of propiophenone with formaldehyde and dimethylamine affords the corresponding aminoketone.
  2. 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.
  3. Esterification of the alcohol by means of propionic anhydride affords the propionate.[4]

Chirality[edit]

The presence of two chiral centers in this molecule means, of course, that the compound will exist as two racemic pairs. 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 useful antitussive activity and is named levopropoxyphene.[citation needed]

References[edit]

  1. ^ Reference.MD: Propoxyphene napsylate
  2. ^ Lutje Spelberg; Jeffrey Harald (2003). "Enantioselective biocatalytic conversions of epoxides". Rijksuniversiteit Groningen. 
  3. ^ Chenier, Philip J. (2002) Survey of Industrial Chemistry. Springer. ISBN 0306472465. p. 455.
  4. ^ Pohland, A.; Sullivan, H. R. (1953). "Analgesics: Esters of 4-Dialkylamino-1,2-diphenyl-2-butanols". Journal of the American Chemical Society 75 (18): 4458–4461. doi:10.1021/ja01114a019.