90 mg of pyridine-2-carboxylic acid and 190 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide monohydrochloride were added in order to a pyridine (2 ml) solution of 181 mg of t-butyl 2-(4-amino-2-fluoro-phenyl)-pyrrolidine-1-carboxylate, and the reaction liquid was stirred at room temperature for 3 hours. The reaction liquid was diluted with chloroform, washed with water and saturated saline, and dried with anhydrous magnesium sulfate. The solvent was evaporated away under reduced pressure, and 2 ml of 4 N hydrochloric acid-dioxane solution was added to 300 mg of the resulting residue, and the reaction liquid was stirred at room temperature for 1 hour. The reaction liquid was diluted with chloroform, and made basic with aqueous saturated sodium bicarbonate solution added thereto, and the organic layer was washed with saturated saline and dried with anhydrous magnesium sulfate. The solvent was evaporated away under reduced pressure, and 0.020 ml of acetic anhydride was added to a pyridine (1 ml) solution of the resulting residue, and the reaction liquid was stirred at room temperature for 20 minutes. The reaction liquid was diluted with chloroform, washed with water and saturated saline in order, and dried with anhydrous magnesium sulfate. The solvent was evaporated away under reduced pressure, and the resulting residue was purified through silica gel column chromatography (developing solvent: chloroform/methanol=50/1) to obtain the entitled compound as a yellow solid.
