To a cold (0° C.) mixture of 3-(2-amino-3-cyano-6-{2-[(4-methoxybenzyl)oxy]phenyl}-4-pyridinyl)benzoic acid (starting compound 5, 1.35 g, 3.00 mmol), N-(2-aminoethyl)piperidine (0.420 g, 3.30 mmol), and 1-hydroxybenzotriazole (0.490 g, 3.60 mmol) was added 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (0.69 g, 3.60 mmol) with stirring. The mixture was allowed to warm to room temperature and stirred overnight. The reaction mixture was concentrated under reduced pressure. The residue was dissolved in ethyl acetate and partitioned between ethyl acetate and water. The separated organic phase was washed with brine, dried over MgSO4, filtered and concentrated under reduced pressure. The obtained solid was triturated with ethyl ether and dried under reduced pressure to give 2-(1-piperidinyl)ethyl 3-(2-amino-3-cyano-6-{2-[(4-methoxybenzyl)oxy]phenyl}-4-pyridinyl)benzoate (0.98 g, yield 58%).
