(E)-3-{2-[5-methoxy-4-(3-(morpholin-4-yl) propyloxy)-2-nitrophenyl]vinyl}-1H-indazole (0.39 g, 0.89 mmol) obtained in Step 2 was dissolved in ethanol (3.0 mL), and the solution was added with tin (0.22 g, 1.9 mmol) and concentrated hydrochloric acid (1.5 mL) under ice-cooling, followed by stirring at 40° C. for 6 hours. To the reaction mixture under ice-cooling, 6 mol/L aqueous sodium hydroxide solution was added to neutralize the mixture. Then, the mixture was filtered. The filtrate was added with saturated aqueous sodium hydrogencarbonate solution and extracted with ethyl acetate. The organic layer was washed with water and saturated brine, dried over anhydrous magnesium sulfate and the solvent was evaporated under reduced pressure. The filtrate was purified by silica gel column chromatography (chloroform to chloroform/methanol=9/1) to obtain (E)-2-[2-(1H-indazol-3-yl)vinyl]-4-methoxy-5-[3-(morpholin-4-yl)propyloxy]phenylamine (0.32 g, 89%).
