A suspension of 4-(4-bromo-3-cyanopyrazole-1-yl)benzoic acid ethyl ester (0.17 g), (3,4-methylenedioxyphenyl)boronic acid (0.11 g), tetrakis(triphenylphosphine) palladium (0.12 g) and sodium carbonate (0.17 g) in a mixed solvent of water (0.5 mL) and N,N-dimethylformamide (5 mL) was stirred at 70° C. for 12 hours. To this reaction mixture was added dilute hydrochloric acid, and this mixture was extracted with ethyl acetate. This organic layer was washed with brine, dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure. The residue was purified by column chromatography on aminopropyl silica gel (eluent: ethyl acetate/n-hexane=1/5) to give the title compound (0.05 g).
