Yield:-

Reaction Conditions:

with hydrogen bromide;bromine;acetic acid at 20;Inert atmosphere;

Steps:

Intermediate 17 2-Bromo-1 -[4-chloro-3-(trifluoromethyl)phenyl]ethanone

1 - [4-chloro-3-(trifluoromethyl)phenyl]ethanone (3.76 g, 16.9 mmol, CAS 129825-1 1 -2) was dissolved in acetic acid (15,5 mL), and bromine (870 μΙ_, 17 mmol) and hydrogen bromide (46 μΙ_, 840 μιηοΙ) were added. The reaction mixture was stirred overnight at room temperature. Then the reaction was poured into iced water, adjusted to pH 5 with aqueous sodium hydrogencarbonate solution, the brown precipitate was filtered off, washed with water and dried, to obtain 3.50 g of the crude title compound LC-MS (Method 1): R_t = 1.29 min; MS (ESIpos): m/z = 301 [M+H]⁺

References:

WO2019/25562,2019,A1 Location in patent:Page/Page column 227; 237