1,3-Cyclohexanedione

1,3-Cyclohexanedione is an organic compound with the formula ₄₂. 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.

Synthesis, structure, and reactivity

1,3-Cyclohexanedione is produced by semi-hydrogenation of resorcinol:
1,3-Cyclohexanedione exists in solution predominantly as the enol tautomer.
It reacts under acid catalysis with alcohols to 3-alkoxyenones. Its pK_a 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.

Derivatives

Dimedone is a well established reagent.
Several herbicides against grasses are formal derivatives of 1,3-cyclohexanedione. Examples of commercial products include cycloxydim, clethodim, tralkoxydim, butroxydim, sethoxydim, profoxydim, and mesotrione.
1,3-Cyclohexanedione is also used in the manufacture of Ondansetron.