To a mixture of 4-{[1-(3-methyl-1-benzofuran-2-yl)-2-phenoxyethyl]amino}benzoic acid (100 mg) synthesized above, β-alanine ethyl ester hydrochloride (59.4 mg), 1-hydroxybenzotriazole monohydrate (59.3 mg), triethylamine (72 μL) and N,N-dimethylformamide (10 mL) was added 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (74.2 mg), and the mixture was stirred overnight at room temperature. 1N Hydrochloric acid was added to quench the reaction, and the mixture was extracted with ethyl acetate. The extract was washed with saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (45% ethyl acetate/hexane) to give the title object compound (63.0 mg, 50%) as a pale-yellow oil.
