Hydrogen Bromide → 2,4-Dichloro-5-fluoro-3-methoxybromobenzene

Participants

Reaction Conditions

Reaction Steps

To 165 ml of a mixture of concentrated hydrochloric acid and water (1:1) was added 52.5 g of 2,4-dichloro-5-fluoro-3-methoxyaniline (0.25 mol). The resultant was stirred to be a slurry, and cooled to 0-5° C. Over 30 minutes, a solution of sodium nitrite (18.2 g) in water (50 ml) was added dropwise to the slurry. The resulting solution was added slowly to a solution of cuprous bromide (0.299 mol) and hydrobromic acid (160 ml). The reactant was stirred for 2 hours, and kept overnight. The resulting mixture was wet-distilled and the distilled materials were extracted with toluene. The oil layer was washed with 10% aqueous solution of NaOH, concentric sulfuric acid and water, dried over anhydrous sodium sulfate, and evaporated. The residue was purified by silica gel chromatography eluting with n-hexane-dichloromethane to give 58.1 g of 2,4-dichloro-5-fluoro-3-methoxybromobenzene (0.212 mol) in 84.9% yield.

Provenance & Evidence