To a solution of 1-(3-diethylaminopropyl)-3-[4-(2-fluoro-4-nitrophenoxy)pyridin-2-yl]-1-methylurea (503 mg) in methanol (40 ml)-tetrahydrofuran (20 ml) was added 10% palladium on carbon (200 mg), followed by stirring under a hydrogen atmosphere at room temperature for 12 hr. The catalyst was removed by filtration and washed with methanol, and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (Fuji Silysia NH, ethyl acetate, then ethyl acetate:methanol=10:1) to provide the titled compound as a yellow oil (467 mg, 85.6%).
