3-Trifluoromethylbenzyl bromide (0.03 mL, 0.165 mmol, d=1.565) and tetrabutyl ammonium iodide (catalytic amount) are added to a 0° C. suspension of 2-(2-Fluoro-phenoxy)-2-methyl-3-{4-[2-(3-methyl-2-oxo-imidazolidin-4-yl)-ethoxy]-phenyl}-propionic acid ethyl ester (0.049 g, 0.110 mmol) and sodium hydride (0.011 g, 0.276 mmol, 60% suspension on mineral oil), pre-stirred for 1 h at ambient temperature. The reaction mixture is stirred at ambient temperature for 18 h, diluted with ethyl acetate, and washed. The organic layer is dried, concentrated, and carried into the next step. MS [EI+] 603 (M+H)+.
