764 mg of white crystals were obtained using 3.0 mg (13 mmol, Production Example 13b) of ethyl-7-amino-2-chloroquinoline-4-carboxylate and 2.3 g (13 mmol) of 3-pyridinesulfonyl chloride in the same manner as in Synthetic Example 1b. An aqueous 1 N sodium hydroxide solution (0.5 ml) was added to an ethanol solution (6 ml) of 108 mg (0.28 mmol) of the white crystals, followed by stirring overnight. An aqueous 1 N hydrochloric acid solution was added to the reaction solution, followed by extracting with ethyl acetate twice. The organic layer was washed with brine, dried over magnesium sulfate and concentrated, to give the residue. Under ice-cooling, oxalyl chloride (0.04 ml) and one droplet of dimethylformamide were added to a tetrahydrofuran solution (10 ml) containing the residue, followed by stirring at room temperature for 30 minutes. After 30 minutes, an aqueous saturated ammonium solution (5 ml) was added thereto, followed by stirring for further 10 minutes. Brine was added to the reaction solution, followed by extracting with ethyl acetate. The organic layer was dried over magnesium sulfate and concentrated, to give the residue. Under ice-cooling, pyridine (0.06 ml) and trifluoroacetic acid anhydride (0.05 ml) were added to a tetrahydrofuran solution (6 ml) containing the residue, followed by stirring at room temperature for 30 minutes. Brine was added to the reaction solution, followed by extracting with ethyl acetate. The organic layer was dried over magnesium sulfate and concentrated. The residue was purified by silica gel chromatography, to give 37 mg of the title compound.
