Tropinone

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Tropinone
IUPAC name 8-Methyl-8-azabicyclo[3.2.1]octan-3-one
Other names 3-Tropinone
Identifiers
CAS number [532-24-1]
PubChem 446337
SMILES O=C1CC2N(C)C(CC2)C1
Properties
Molecular formula C8H13NO
Molar mass 139.195 g/mol
Appearance Brown solid
Melting point

42.5 °C, 316 K, 109 °F
Boiling point

(decomposes)
Hazards
NFPA 704

1
2
0
 
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Tropinone is an alkaloid, first synthesised in 1917 by Robert Robinson as a synthetic precursor to atropine, a scarce commodity during World War I.[1] [2] Tropinone and the alkaloids cocaine and atropine all share the same tropane core structure.

Contents

[edit] Synthesis

In organic chemistry the first laboratory preparation of tropinone is considered a milestone in total synthesis. Tropinone is a bicyclic molecule, but the reactants used in its preparation are fairly simple: succinaldehyde, methyl amine and acetone dicarboxylic acid (or even acetone). The synthesis is a good example of a biomimetic reaction or biogenetic-type synthesis because biosynthesis makes use of the same building blocks. It also demonstrates a tandem reaction in a one-pot synthesis.

[edit] Reaction mechanism

The main features apparent from the reaction sequence below are:

  1. Nucleophilic addition of secondary amine to aldehyde followed by loss of water to create an imine
  2. Nucleophilic addition of the imine to the second aldehyde unit and first ring closure
  3. Intermolecular mannich reaction of the enolate of actone dicarboxylate
  4. New enolate formation and new imine formation with loss of water for
  5. Second intramolecular mannich reaction and second ring closure
  6. Loss of 2 carboxylic groups to tropinone
Tropinone synthesis

[edit] References

  1. ^  R. Robinson (1917). "A synthesis of tropinone". Journal of the Chemical Society, Transaction 111: 762 - 768. DOI:10.1039/CT9171100762. 
  2. ^  The Art and Science of Total Synthesis at the Dawn of the Twenty-First Century K. C. Nicolaou, Dionisios Vourloumis, Nicolas Winssinger, and Phil S. Baran Angew. Chem. Int. Ed. 2000, 39, 44 ± 122

[edit] External links

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