First, 3.02 g of N-[2-fluoro-5-(2-hydroxyphenoxy)-4-nitrophenyl]acetamide was dissolved in 20 ml of N,N-dimethylformamide, to which 1.5 g of potassium carbonate was added, and the mixture was stirred at room temperature for 1 hour. Then, 1.6 g of methyl bromoacetate was added at room temperature. After stirring at the same temperature for 2 hours, the mixture was poured into water, and the mixture was extracted with ethyl acetate. The organic layer was washed with diluted hydrochloric acid and water, dried over magnesium sulfate, and then concentrated. The resulting crystals were washed with t-butyl methyl ether to give 3.01 g of methyl [2-(5-acetylamino-4-fluoro-2-nitrophenoxy)phenoxy]acetate.
