3,5,5-Trimethylcyclohexane-1,2-dione

Preparation

1.1 Purification of Isophorone

Isophorone is a colorless, readily polymerizable liquid with a boiling point of 212–213 °C. It is prepared by condensation of acetone under alkaline conditions. Crude isophorone was collected by vacuum distillation at 84–85 °C/1.6 kPa, and stored in the dark for later use.

1.2 Synthesis of 2,3-Oxyphorone

55 mL of methanol (or ethanol), a certain amount of sodium hydroxide solution, and a phase transfer catalyst were added to a three-necked flask and stirred under an ice-water bath. 20.0 g of isophorone was slowly added dropwise using a constant-pressure funnel, maintaining the reaction temperature at 15 °C. After 20 min, the solution changed from beige to reddish-brown. At this point, 30% hydrogen peroxide was slowly added dropwise, maintaining the reaction temperature as before. After 10 min, the mixture was heated in a water bath, and the color of the reaction solution gradually lightened. The reaction was monitored by TLC.

Uses

3,5,5-Trimethyl-1,2-cyclohexanedione is used in preparation of Tetrahydro-carbazolone analogs as hepatitis C inhibitors.

Definition

ChEBI: 3,5,5-Trimethyl-1,2-cyclohexanedione is a cyclic ketone.