Hexachloroethane → 2-Chloro-3,4-difluorobenzoic acid

Participants

Reaction Steps

To a mixture of N,N,N′,N′-tetramethylethylenediamine (8.40 mL) and tetrahydrofuran (75 mL) was added sec-butyllithium (1.0 mol/L cyclohexane solution, 55.7 mL) under an argon atmosphere at −78° C., and the mixture was stirred for 30 min. A mixture of 3,4-difluorobenzoic acid (4.00 g) and tetrahydrofuran (25 mL) was added dropwise to the reaction mixture at the same temperature over 30 min. After the reaction mixture was stirred for 30 min, a mixture of hexachloroethane (24.0 g) and tetrahydrofuran (40 mL) was added dropwise to the reaction mixture at the same temperature over 30 min. After stirring for 30 min while raising the temperature to room temperature, the reaction mixture was poured into water. The aqueous layer was washed with diisopropyl ether, acidified with 6 mol/L hydrochloric acid and extracted with diethyl ether. The organic layer was washed with brine, dried over anhydrous sodium sulfate, and concentrated. The obtained residue was washed with diethyl ether to give the title product as a solid (yield: 2.95 g).

Provenance & Evidence