6-Methoxy-4-(2-methyl-quinolin-3-yloxy)-quinolin-7-ol (compound 352) (50 mg) and triphenylphosphine (158 mg) were dissolved in tetrahydrofuran (1 ml) to prepare a solution. A solution of diethylazocarbodiimide (105 mg) in (2,2-dimethyl[1,3]dioxan-5-yl)-methanol (27 mg) and tetrahydrofuran (0.2 ml) was added to the solution, and the mixture was stirred at room temperature for 5 hr. A 1 N aqueous sulfuric acid solution (1 ml) was then added to the reaction solution, and the mixture was stirred at room temperature overnight. The reaction solution was made alkaline by the addition of 1 N sodium hydroxide, and the mixture was extracted with ethyl acetate. The ethyl acetate 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 thin layer chromatography using chloroform-methanol to give the title compound (29 mg, yield 45%).
