Tropinone
From Wikipedia, the free encyclopedia
| Tropinone | |
|---|---|
 |
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| IUPAC name | 8-Methyl-8-azabicyclo[3.2.1]octan-3-one |
| Other names | 3-Tropinone |
| Identifiers | |
| CAS number | [] |
| PubChem | |
| 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 |
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Tropinone is an alkaloid, first synthesised in 1917 by Robert Robinson as a synthetic precursor to atropine, a scarce commodity during World War I. 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:
- Nucleophilic addition of secondary amine to aldehyde followed by loss of water to create an imine
- Nucleophilic addition of the imine to the second aldehyde unit and first ring closure
- Intermolecular mannich reaction of the enolate of actone dicarboxylate
- New enolate formation and new imine formation with loss of water for
- Second intramolecular mannich reaction and second ring closure
- Loss of 2 carboxylic groups to tropinone
[edit] References
- ^ R. Robinson (1917). "A synthesis of tropinone". Journal of the Chemical Society, Transaction 111: 762 - 768. DOI:10.1039/CT9171100762.
- ^ 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
