Phenyl chloroformate → 4-(4-Amino-2-fluorophenoxy)-2-{[4-(pyrrolidin-1-yl)piperidin-1-yl]carbonylamino}pyridine

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Reaction Steps

2-Amino-4-(2-fluoro-4-nitrophenoxy)pyridine (187 mg) was dissolved in tetrahydrofuran (4 ml) under a nitrogen atmosphere, and then triethylamine (0.21 ml) and phenyl chloroformate (0.188 ml) were added dropwise thereto while cooling in an ice bath, followed by stirring at room temperature for 20 min. To the reaction mixture were added N,N-dimethylformamide (2 ml) and 4-(pyrrolidin-1-yl)piperidine (609 mg) at room temperature, followed by stirring overnight. The reaction mixture was partitioned between ethyl acetate and water. The organic layer was washed with brine, and dried over anhydrous sodium sulfate. The solvent was evaporated under a reduced pressure to give a residue, to which methanol (10 ml)-tetrahydrofuran (10 ml) was added to dissolve, and then 10% palladium carbon (200 mg) was added thereto under a nitrogen atmosphere, followed by replacing with hydrogen inside the system and stirring overnight. After replacing with nitrogen inside the system, the catalyst was filtered and washed with ethanol. The filtrate was concentrated under a reduced pressure to give a residue, which was purified by silica gel column chromatography (Fuji Silysia NH, eluent; ethyl acetate, then ethyl acetate:methanol=95:5) to provide the titled compound (214 mg, 71%) as colorless crystals.

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