2-BroMo-1-(3,4-dichlorophenyl)butan-1-one synthesis

Yield:-

Reaction Conditions:

with bromine in dichloromethane at 20;Inert atmosphere;

Steps:

1.a.2

Step 2. 2-Bromo-3',4'-dichlorobutyrophenone (10aa). To a solution of 3.91 g (0.018 mol) of 9aa in 70 mL of methylene chloride was added ten drops of bromine. After stirring at room temperature under nitrogen for several minutes, the characteristic red color of bromine disappeared indicating initiation of the reaction. The remainder of the 1 mL (18.30 mmol) of bromine was added dropwise and the reaction solution was allowed to stir at room temperature under nitrogen for 9.5 h. The reaction solution was quenched and brought to a pH of 9 with a saturated aqueous solution of sodium bicarbonate and solid sodium bicarbonate. The product was extracted with methylene chloride, dried (Na₂SO₄), and filtered. The solvent was removed, and the resulting residue was dried briefly under high vacuum to give 5.62 g (>;100%) of lOaa as an orange oil. ¹H NMR (CDCl₃) δ 8.10 (s, IH), 7.86-7.82 (dd, IH), 7.57 (d, IH), 4.95 (t, IH), 2.30-2.07 (m, 2H), 1.09 (t, 3H).

References:

WO2010/121022,2010,A1 Location in patent:Page/Page column 60-61