Hydrogen Bromide → 2-Bromo-1-(4-fluorophenyl)-2-phenylethanone

Participants

Reaction Conditions

Reaction Steps

Methylene chloride (1 L) is taken in a 4 necked RB flask equipped with mechanical strring rod, pressure equalization funnel and a CaCl2 guard tube. 100 g (0.466 mol) of 1-(4-Fluorophenyl)-2-phenyl ethanone is introduced in to the above flask and stirred for 5 minutes to obtain a clear solution.2 ml of a 30% hydrobromic acid in acetic acid is then added, followed by gradual addition of a cold solution of bromine (73 g, 0.456 mole) in 200 ml of methylene chloride at 26±2° C. Bromine solution is added in such a manner that it is consumed instantly as indicated by colouration of reaction mixture. After addition of bromine solution the reaction mixture is cooled to 19±1° C., treated with 5% aqueous sodium sulphite (200 ml) and stirred for about lhr at 21.5±3.5° C. The organic layer is then separated and is subjected to the above operation twice with 5% aqueous sodium sulphite (2×200 ml). The organic layer is then stirred with 5% aqueous sodium bicarbonate (200 ml) for about 1 hr at 21.5±3.5° C. and separated. The organic layer is finally stirred with 5% aqueous sodium chloride(200 ml) and separated. The organic layer is dried over sodium sulphate and filtered. Methylene chloride is removed by distillation and the syrup thus obtained solidified on standing in to a pale orange coloured solid. Yield 129 g (94.8%)

Provenance & Evidence