A solution of 150 mg (0.67 mmol) of 2-(2-isopropyl-5-methylphenoxy)propionic acid in 1 ml of thionyl chloride was boiled under reflux under argon for 30 minutes. The reaction mixture was concentrated, admixed with 2 ml of toluene and concentrated again. The residue was dissolved in 3 ml of acetonitrile under argon, admixed with 940 μl (0.67 mmol) of triethylamine and a solution of 150 mg (0.67 mmol) of ethyl 3-(4-aminophenyl)-3-methoxypropionate and stirred at room temperature for 30 minutes. The reaction mixture was diluted with water, adjusted to pH=6-7 with 1 N hydrochloric acid and extracted with ethyl acetate. The organic phase was dried over MgSO4, filtered and concentrated under high vacuum. This gave 287 mg of ethyl 3-{4-[2-(2-isopropyl-5-methylphenoxy)propionylamino]phenyl}-3-methoxypropionate.
