Diisopropylethylamine → Impurity E of MESOTRIONE

Participants

Reaction Conditions

Reaction Steps

To a mixture of 157 mg (1.15 mmol) of 3-chlorocyclohex-2-en-1-one (prepared as described in Synthesis (1974), (1), 47-8), 16 mg (0.12 mmol) of ZnCl2, 297 mg (1.15 mmol) of 2-nitro-4-methylsulfonylbenzoic acid and 3 ml of anhydrous acetonitrile there are added dropwise, under a nitrogen atmosphere, over the course of 15 minutes, 166 mg (1.27 mmol) of diisopropylethylamine. A further 2 ml of acetonitrile are then added and the reaction mixture is maintained at a temperature of 45° C. for 18 hours in an oil bath, with stirring. The reaction mixture is then heated up again and maintained at reflux temperature for 40 hours. The reaction mixture is then brought to ambient temperature and the solvent is removed in vacuo. 25 ml of dichloromethane and 0.35 g of 36% hydrochloric acid in 5 ml of water are then added and the phases are separated. The organic phase is washed twice with 10 ml of water, dried using magnesium sulfate and concentrated in vacuo. 197 mg of 3-(2-nitro-4-methylsulfonyl-phenylcarbonyloxy)-cyclohex-2-en-1-one are obtained in the form of a brown oil.

Provenance & Evidence