To a solution of methyl 4-[1-[4-[1-(S)-(4-isobutylphenyl)butoxy]benzoyl]indolizin-3-yl]butyrate (182 mg) in ethanol (4 ml) was added 1N aqueous solution of sodium hydroxide (0.6 ml). The mixture was stirred at 50° C. for 40 minutes, and then poured into a mixture of ethyl acetate and diluted hydrochloric acid. The organic layer was separated, washed with water, dried over magnesium sulfate and evaporated. The residue was crystallized with diisopropyl ether to give 4-[l-[4-[l-(S)-(4-isobutylphenyl)butoxy]benzoyl]indolizin-3-yl]butyric acid as white powder (89 mg).
