5,5-dimethyl)-1,3-cyclohexanedione (Dimedone) (126-81-8)

An air-stable, white solid when pure, dimedone is a convenient starting material in the synthesis of more elaborate molecules.[1] It is also known to form crystalline products in the presence of aldehydes. The compound can be purchased at a cheap-to-modest price from many chemical vendors.

Procedure: Dimedone can be synthesized in good yields via the Michael addition of diethyl malonate to mesityl oxide according to an Organic Syntheses procedure.[2]

Notes:

  • The compound exists in equilibrium with its enol tautomer apparent by NMR (diagnostic singlet for alkene C2 proton at 5.5 ppm, whereas the C2 protons of the 1,3-dione appear at 3.3 ppm in CDCl3) . The ratio is approximately 2:1 in favor of the 1,3-dione.

[1] Wright, A. J.; Colclough, D.; Harris, H.; Biagini, S. C. G. J. Chem. Educ. 2023, 100, 8, 3025-3028.
[1] Shriner, R. L.; Todd, H. R. Org. Synth. 1935 , 15 , 14. DOI: 10.15227/orgsyn.015.0014