Phenyl N-(2-chloro-4-(7-methoxy-6-methoxycarbonyl-4-quinolyl)oxyphenyl)carbamate (1.92 g, 4.00 mmol) and 2 M ethylamine (tetrahydrofuran solution) (4 ml) were stirred in dimethylformamide (8 ml) at room temperature for 30 minutes. The reaction solution was distributed between ethyl acetate and water, the organic layer was washed with water and saturated saline and dried over anhydrous magnesium sulfate, and the drying agent was filtered out and the filtrate distilled off under reduced pressure. The obtained crude product was suspended in ethyl acetate, the suspension was diluted with hexane, and the crystals were filtered out, washed with hexane and blow-dried to obtain the title compound (1.60 g, 3.72 mmol, 93%) as white crystals.
