Chemistry:Dimedone

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Dimedone
Dimedone.png
Dimedone-3D-balls.png
Names
Preferred IUPAC name
5,5-Dimethylcyclohexane-1,3-dione
Other names
Cyclomethone,
5,5-dimethyl-1,3-cyclohexanedione,
Dimethyldihydroresorcinol,
Methone
Identifiers
3D model (JSmol)
ChemSpider
UNII
Properties
C8H12O2
Molar mass 140.182 g·mol−1
Appearance White solid
Melting point 147 to 150 °C (297 to 302 °F; 420 to 423 K) (decomposes)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Dimedone is an organic compound with the formula (CH
3
)
2
C(CH
2
)
2
(CO)
2
(CH
2
)
. Classified as a cyclic diketone, it is a derivative of 1,3-cyclohexanedione. It is a white solid that is soluble in water, as well as ethanol and methanol. It once was used as a reagent to test for the aldehyde functional group.

Synthesis

Dimedone is prepared from mesityl oxide and diethyl malonate via a Michael addition reaction.[1][2]

Chemical properties

Tautomerism

Dimedone is in equilibrium with its tautomer in solution — in a 2:1 keto to enol ratio in chloroform.[3]

Diagram of tautomeric equilibrium of dimedone

Crystalline dimedone contains chains of molecules, in the enol form, linked by hydrogen bonds:[4]

Ball-and-stick model of a hydrogen-bonded dimedone chain, as found in the crystal structure

Reaction with aldehydes

Dimedone reacts with aldehydes to give crystalline derivatives, whose melting points can be used to distinguish between aldehydes.[5]

File:Fällung dimedon.tif

References

  1. R. L. Shriner and H. R. Todd (1935). "5,5-dimethyl-1,3-cyclohexanedione". Organic Syntheses 15: 16. doi:10.1002/0471264180.os015.06. ISBN 0471264229. http://www.orgsyn.org/orgsyn/prep.asp?prep=cv2p0200. 
  2. "Dimedone synthesis" (in en). https://www.chemtube3d.com/conjugate-addition-dimedone-synthesis/. 
  3. Clayden, Jonathan; Greeves, Nick; Warren, Stuart; Wothers, Peter (2001). Organic Chemistry (1st ed.). Oxford University Press. p. 530. ISBN 978-0-19-850346-0. 
  4. M. Bolte and M. Scholtyssik (October 1997). "Dimedone at 133K". Acta Crystallogr. C 53 (10): IUC9700013. doi:10.1107/S0108270197099423. 
  5. Horning, E. C.; Horning, M. G. (1946). "Methone Derivatives of Aldehydes" (in en). The Journal of Organic Chemistry 11 (1): 95–99. doi:10.1021/jo01171a014. ISSN 0022-3263. PMID 21013441. https://pubs.acs.org/doi/abs/10.1021/jo01171a014.