Tropinone

Tropinone

Names
IUPAC name 8-Methyl-8-azabicyclo[3.2.1]octan-3-one
Other names 3-Tropinone
Identifiers
CAS Number	532-24-1 N
3D model (Jmol)	Interactive image
ChEBI	CHEBI:16656 Y
ChemSpider	393722 Y
DrugBank	DB01874 Y
ECHA InfoCard	100.007.756
PubChem	446337
InChI InChI=1S/C8H13NO/c1-9-6-2-3-7(9)5-8(10)4-6/h6-7H,2-5H2,1H3/t6-,7+ Y Key: QQXLDOJGLXJCSE-KNVOCYPGSA-N Y InChI=1S/C8H13NO/c1-9-6-2-3-7(9)5-8(10)4-6/h6-7H,2-5H2,1H3/t6-,7+ Key: QQXLDOJGLXJCSE-KNVOCYPGBG Key: QQXLDOJGLXJCSE-KNVOCYPGSA-N
SMILES CN1[C@@H]2CC[C@H]1CC(=O)C2
Properties
Chemical formula	C8H13NO
Molar mass	139.195 g/mol
Appearance	Brown solid
Melting point	42.5 °C (108.5 °F; 315.6 K)
Boiling point	(decomposes)
Hazards
NFPA 704	1 2 0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Tropinone is an alkaloid, famously 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.

The first synthesis of tropinone was by Richard Willstätter in 1901. It started from the seemingly related cycloheptanone, but required many steps to introduce the nitrogen bridge; the overall yield for the synthesis path is only 0.75%. Willstätter had previously synthesized cocaine from tropinone, in what was the first synthesis and elucidation of the structure of cocaine.

The 1917 synthesis by Robinson is considered a classic in total synthesis due to its simplicity and biomimetic approach. Tropinone is a bicyclic molecule, but the reactants used in its preparation are fairly simple: succinaldehyde, methylamine and acetonedicarboxylic 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. Furthermore, the yield of the synthesis was 17% and with subsequent improvements exceeded 90%.

This reaction is described as an intramolecular "double Mannich reaction" for obvious reasons. It is not unique in this regard, as others have also attempted it in piperidine synthesis.