1,3-Dibromobenzene → HCID 57825196, compound

Participants

Reaction Conditions

Reaction Steps

A solution of n-butyllithium (1.6 M in hexane, 16.4 mL, 26.2 mmol, 1.16 eq.) was added dropwise over 20 min to a solution of 1,3-dibromobenzene (3.00 mL, 24.8 mmol, 1.1 eq) in 25 mL of dry tetrahydrofuran at −78° C. and under an inert atmosphere. The white suspension formed was stirred at −78° C. for 30 min. A solution of 1-(3-chloro-4-difluoromethoxy-phenyl)-ethanone (7 g, 31.7 mmol, 1.0 eq.) in 25 mL of tetrahydrofuran was then added dropwise and the reaction stirred for 1 h. The reaction mixture was examined by LC-MS which showed the complete formation of tertiary alcohol. The solution was quenched with a saturated solution of ammonium chloride and water. 2 N HCl was then added to reach pH=5. The two phases were separated; the organic layer was dried over anhydrous magnesium sulfate, filtered and evaporated under reduced pressure. The crude (tertiary alcohol) and a catalytic amount of p-toluenesulfonic acid were dissolved in 70 mL toluene (Dean-Stark apparatus) and the mixture was heated to reflux for 3 h. The solution was examined by TLC (cyclohexane) which showed consumption of starting material but many side products formed. Solvent was evaporated under reduced pressure and the crude residue was purified by flash chromatography eluting with cyclohexane. The desired product was obtained as yellow oil (2.2 g, Yield: 27%).

Provenance & Evidence