3-Hydroxy-2-methyl-4-quinoline carboxylic acid (549 mg), 6-benzyloxy-4-chloro-7-methoxyquinoline (810 mg), and 4-(N,N-dimethylamino)-pyridine (990 mg) were dissolved in 1,2-dichlorobenzene (40 ml) to prepare a solution. The mixture was stirred at 150° C. overnight. The reaction solution was cooled to room temperature, and the solvent was then removed by distillation under the reduced pressure. Water was added to the residue, and the mixture was extracted with chloroform. The chloroform layer was washed with water and was then dried over anhydrous sodium sulfate. The solvent was removed by distillation under the reduced pressure, and the residue was purified by column chromatography using hexane-acetone to give the title compound (718 mg, yield 63%).
