Toluene (20 ml) and thionyl chloride (1 ml) were added to commercially available 2,5-dimethyl-3-furoic acid (80 mg), and the mixture was heated at 100° C. for one hr. The solvent was removed by distillation, and 2,5-dimethyl-3-furancarbonyl isothiocyanate was prepared using the resultant 2,5-dimethyl-3-furancarbonyl chloride as a starting compound according to the description of the literature. 2,5-Dimethyl-3-furancarbonyl isothiocyanate was dissolved in ethanol (1 ml) to prepare a solution. 4-[(6,7-Dimethoxy-4-quinolyl)oxy]-2-fluoroaniline (50 mg), toluene (5 ml), and ethanol (1 ml) were added to the solution, and the mixture was stirred at room temperature for 2 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 (38 mg, yield 48%).
