Hydrochloric Acid → 3,4-Dichloro-2-fluorotoluene

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Under an argon atmosphere, to a solution (75 mL) of N,N,N′,N′-tetramethylethylenediamine (16.15 g) in dry tetrahydrofuran was added a solution (139 mL) of 1 mol/L-sec-butyllithium in hexane/cyclohexane under cooling (dry ice-acetone bath) at not higher than −60° C., and the mixture was stirred at the same temperature for 20 min. The mixture was further cooled to −78° C., and a solution (50 mL) of 4-chloro-2-fluoro-1-methylbenzene (18.26 g) in dry tetrahydrofuran was added thereto. After the reaction mixture was stirred at the same temperature for 30 min, a solution (275 mL) of hexachloroethane (119.6 g) in dry tetrahydrofuran was added dropwise thereto. The mixture was stirred at the same temperature for 30 min to gradually warm to room temperature. To the reaction mixture was added 6 mol/L hydrochloric acid to adjust to pH=5 and the mixture was concentrated. The residue was partitioned between ether and water, and the organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and concentrated. The residue was placed on a glass filter, washed with a small amount of ether and filtrated. The filtrate was concentrated and evaporated under reduced pressure. The fraction at the boiling point of 48° C. (1.5 Torr) was collected to give the title compound as a colorless oil (yield: 19 g).

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