1,3-Cyclohexanedione Explained

1,3-Cyclohexanedione is an organic compound with the formula (CH2)4(CO)2. It is one of three isomeric cyclohexanediones. It is a colorless compound that occurs naturally. It is the substrate for cyclohexanedione hydrolase. The compound exists mainly as the enol tautomer.[1]

Synthesis, structure, and reactivity

1,3-Cyclohexanedione is produced by semi-hydrogenation of resorcinol:[2]

C6H4(OH)2 + H2 → C6H8O2

1,3-Cyclohexanedione exists in solution predominantly as the enol tautomer.

It reacts under acid catalysis with alcohols to 3-alkoxyenones.[1] Its pKa is 5.26. Treatment of the sodium salt of the enolate with methyl iodide gives 2-methyl-1,3-cyclohexanedione, which also exists predominantly as the enol.[3]

Derivatives

Dimedone (5,5-dimethyl-1,3-cyclohexanedione) is a well established reagent.[4]

Several herbicides against grasses are formal derivatives of 1,3-cyclohexanedione. Examples of commercial products include cycloxydim, clethodim, tralkoxydim, butroxydim, sethoxydim, profoxydim, and mesotrione.[5]

Notes and References

  1. 1,3-Cyclohexadiene. Sanjeeva Rao. Guppi. George A.. O'Doherty . 2008. 10.1002/047084289X.rn00921. E-EROS Encyclopedia of Reagents for Organic Synthesis. 978-0471936237.
  2. Dihydroresorcinol. R. B. . Thompson. Org. Synth.. 1947. 27. 21. 10.15227/orgsyn.027.0021.
  3. Methyl-1,3-Cyclohexanedione. A. B. . Mekler. S.. Ramachandran. S.. Swaminathan. Melvin S.. Newman. Org. Synth.. 1961. 41. 56. 10.15227/orgsyn.041.0056.
  4. Book: 10.1002/14356007.a16_063.pub2. Malonic Acid and Derivatives . Ullmann's Encyclopedia of Industrial Chemistry . 2007 . Strittmatter . Harald . Hildbrand . Stefan . Pollak . Peter . 978-3527306732 .
  5. Cyclohexane-1,3-dione Oxime Ether Grass-Specific Herbicides and the Discovery of Butroxydim. Keith G. Watson. Aust. J. Chem.. 2011. 64. 4. 367–372. 10.1071/CH10366.