To a mixture of 1-((4-(2-fluoro-4-nitrophenoxy)quinolin-7-yl)oxy)-2-methylpropan-2-ol (10.04 g, 27 mmol) and HCOOK (15.87 g, 189 mmol) in THF/H2O (54 mL, THF/H2O=4:1) was added catalytic amount of Pd/C (5%, 53%˜55% water content, w/w). The reaction was stirred at 45° C. for 5 hours, and then diluted with THF/H2O (40 mL, v/v=1:1). The resulted mixture was filtered and the filtrate was concentrated in vacuo. The residue was washed with EtOH/H2O (30 mL×3, v/v=5:1), and dried in vacuo at 45° C. for 24 hours to give the title compound as a light gray solid (8.1 g, 87%).
