To a solution of ethyl 4-[3-[4-[1-(4-isobutylphenyl)hexyloxy]benzoyl]indol-1-yl]butyrate (270 mg) in ethanol (3 ml) and 1,4-dioxane (3 ml) was added 1 N aqueous solution of sodium hydroxide (1.5 ml). The mixture was stirred at room temperature for 3 hours, and then poured into a mixture of ethyl acetate and 0.5N hydrochloric acid. The organic layer was separated, washed with water and brine, dried over magnesium sulfate and evaporated to give 4-[3-[4-[1-(4-isobutylphenyl)hexyloxy]benzoyl]indol-1-yl]butyric acid (230 mg) as powder.
