Reaction #302900

Reaction equation

triethylamine

oxalyl dichloride

2-methoxy-3-methylthio-4-(trifluoromethyl)benzoic acid

1,3-cyclohexanedione

hydrochloric acid

→

3-(2-methoxy-3-methylthio-4-(trifluoromethyl)benzoyloxy)-cyclohex-2-enone

Yield 47.0%

Solvents

dichloromethane

dichloromethane

Conditions

Workup

1. 1
   Temperaturethe mixture was heated
2. 2
   Temperatureunder reflux for another 10 min
3. 3
   OtherAfter phase separation
4. 4
   OtherThe residue was purified chromatographically

Procedure

133 mg (1.05 mmol) of oxalyl dichloride and three drops of N,N-dimethylformamide were added in succession to 200 mg (purity 78% by weight, 0.59 mmol) of 2-methoxy-3-methylthio-4-(trifluoromethyl)benzoic acid in 20 ml of dichloromethane. After the elimination of gas had ceased, the mixture was heated under reflux for another 10 min. The content was then cooled to RT and freed from the solvent. 93 mg (0.83 mmol) of 1,3-cyclohexanedione were added to the residue in 20 ml of dry dichloromethane, and 152 mg (1.50 mmol) of triethylamine were then added dropwise. The mixture was stirred at RT for 16 h. For work-up, 3 ml of 1M hydrochloric acid were added to the contents. After phase separation, the organic phase was freed from the solvent. The residue was purified chromatographically, which isolated 100 mg of 3-(2-methoxy-3-methylthio-4-(trifluoromethyl)benzoyloxy)-cyclohex-2-enone.

Source