In a reaction vessel, 2-[4-(2-hydroxy-ethyl)-phenyl]-2-methyl-propionic acid methylester (2 g) prepared in the Examples 1-3, triethylamine (1.1 g), p-toluenesulfonylchloride (1.9 g) and dichloromethane (20 mL) were introduced, and the mixture was reacted at room temperature for 1 hour. Distilled water (50 mL) was added thereto, and the mixture was stirred to separate layers. The separated organic layer was dehydrated with Na2SO4, and then condensed by filtration to obtain 2-methyl-2-{4-[2-(toluene-4-sulfonyloxy)-ethyl]-phenyl}-propionic acid methylester (3.0 g, yield 91%).
