Hydrochloric Acid → 2-(2,4-Dichlorobenzoyl)-4,4-dimethylcyclohexane-1,3-dione

Participants

Reaction Steps

4,4-Dimethyl-1,3-cyclohexanedione [14.0 grams (g), 0.1 mole], 20.0 g (0.1 mole) 2,4-dichlorobenzoyl cyanide and 13.6 g (0.11 mole) anhydrous, powdered zinc chloride were combined in 100 milliliters (ml) methylene chloride. Triethylamine (10.1 g, 0.12 mole) was slowly added with cooling. The reaction mixture was stirred at room temperature for 5 hours and then poured into 2N hydrochloric acid. The aqueous phase was discarded and the organic phase was washed with 150 ml 5% Na2CO3 four times. The aqueous washings were combined and acidified with HCl, extracted with methylene chloride, dried and concentrated to yield 25.3 g of crude product. The crude product was chromatographed (2% AcOH/CH2Cl2) in 5 g aliquots then reduced on rotavap under reduced pressure at 50° C. for 30 minutes to remove AcOH. This yielded an oil (40% yield). The structure was confirmed by instrumental analysis.

Provenance & Evidence