Methyl 8-(2-hydroxy-5-methyl-phenyl)-8-oxo-octanoate (271 mg), 4-chloro-6,7-dimethoxyquinoline (220 mg), and 4-dimethylaminopyridine (237 mg) were suspended in o-dichlorobenzene (20 ml) to prepare a suspension which was then stirred at 120° C. overnight. The reaction solution was cooled to room temperature, and the solvent was removed by distillation under the reduced pressure. Water was then added to the residue, and the mixture was extracted with chloroform. The chloroform layer was washed with water and was dried over anhydrous sodium sulfate. The solvent was removed by distillation under the reduced pressure, and the residue was purified by column chromatography using acetone-hexane to give the title compound (16 mg, yield 3.5%).
