Toluene (20 ml) and thionyl chloride (1 ml) were added to commercially available 2-methylpentanoic acid (80 mg), and the mixture was heated at 100° C. for one hr. The solvent was removed by distillation, and 2-methylpentanoyl isothiocyanate was prepared using the resultant 2-methylpentanoyl chloride as a starting compound according to the description of the literature. The resultant 2-methylpentanoyl isothiocyanate was dissolved in ethanol (1 ml) to prepare a solution. 3-Chloro-4-[(6,7-dimethoxy-4-quinolyl)oxy]aniline (50 mg), toluene (5 ml), and ethanol (1 ml) were added to the solution, and the mixture was stirred at room temperature for 16 hr. The reaction solution was concentrated, and the residue was purified by chromatography on silica gel using chloroform/acetone for development to give the title compound (69 mg, yield 94%).
