4-(2-BroMoethyl)-1,2-difluorobenzene synthesis

Yield:-

Reaction Conditions:

with sodium bicarbonate;sulfuric acid;hydrogen bromide

Steps:

1 Preparation of 3,4-difluorophenethylbromide

Preparation of 3,4-difluorophenethylbromide 17.59 g (111 mmol) of 2-(3,4-difluorophenyl)ethanol, 16 ml (137 mmol) of hydrogen bromide, 6.8 ml (234 mmol) of conc. sulfuric acid were added in the order, and the mixture was heated under reflux for 3 hrs. The reaction mixture was poured onto an ice-bath, an organic layer and an aqueous layer were separated, the aqueous layer was extracted with ether, the extract combined with the organic layer was washed with a saturated aqueous solution of sodium hydrogen carbonate, and dried over anhydrous magnesium sulfate. The solvent was distilled off, the solution condensed and purified by vacuum distillation to obtain 21.96 g (bp 68-70° C./2-4 Torr.) of oily product. The oily product was purified by column chromatography (elution solvent: hexane:ethyl acetate=3:1), the elude was further purified by vacuum distillation to obtain 19.79 g of the title compound (81%, bp 73-75° C./4 Torr.) as oily product.

References:

US2002/66888,2002,A1