Bromoacetyl bromide → {2-[(2-Bromoacetyl)-(2-chloro-5-fluorophenyl)amino]-1,1-dimethylethyl}carbamic acid t-butyl ester

2.2 ml of bromoacetyl bromide (25.2 mmol) was added to a solution of 5.3 g of [2-(2-chloro-5-fluorophenylamino)-1,1-dimethylethyl]carbamic acid t-butyl ester obtained in Example (62a) (16.8 mmol) in N,N-dimethylacetamide (170 ml) under ice-cooling, and the mixture was stirred at the same temperature for 15 minutes. A saturated sodium bicarbonate aqueous solution was added to the reaction mixture, followed by extraction with ethyl acetate. Then, the organic layer was washed with water and brine and dried over anhydrous magnesium sulfate. After filtration, the solvent was evaporated under reduced pressure. Hexane was added to the residue, and the solid was collected by filtration to obtain 5.8 g of the title compound (yield: 80%).