To a solution of 3-(2-chloro-6-fluorophenyl)-1-[trans-3-(diethylamino)-cyclobutylmethyl]-4-trifluoromethyl-3-hydroxy-6-iodo-1,3-dihydro-2H-indol-2-one (3.60 g, 5.89 mmol) in ethyl acetate (50 mL) was added (S)-α-methoxyphenylacetic acid (550 mg), and the mixture was heated to 6° C. and stirred for 1 hour. Then, the mixture was stirred at room temperature for 1 hour, and thereto was added hexane (10 mL), and the mixture was stirred for additional 30 minutes at room temperature. The precipitated solid was filtered (1.41 g). The solid was recrystallized from ethyl acetate (20 mL)/hexane (3.0 ml) to give (S)-methoxyphenylacetate of 3-(2-chloro-6-fluorophenyl)-1-[trans-3-(diethylamino)-cyclobutylmethyl]-4-trifluoromethyl-3-hydroxy-6-iodo-1,3-dihydro-2H-indol-2-one (970 mg). The resulting compound was converted to its nonsalt form. Thus, the titled compound (650 mg, 98% ee, 18% y.) was obtained.
