Sodium Hydroxide → [4-(2-Aminopyridin-4-yloxy)-3-fluorophenyl]carbamic acid benzyl ester

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Reaction Steps

[4-(4-Benzyloxycarbonylamino-2-fluorophenoxy)pyridin-2-yl]carbamic acid tert-butyl ester (510 mg) was added to a 4N hydrochloric acid-ethyl acetate (30 ml) while cooling in an ice water bath. The reaction mixture was allowed to warm to room temperature and then stirred for 16 hours. Diethyl ether (10 ml) and 5N aqueous sodium hydroxide (1 ml) were added to the reaction mixture and stirred therewith for 30 minutes. The separated organic layer was washed with saturated aqueous sodium hydrogencarbonate (20 ml), water (20 ml) and brine (20 ml) and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and then the resultant residue was purified by silica gel column chromatography (Fuji Silysia NH, eluent; heptane:ethyl acetate=1:2) and fractions containing the target compound were concentrated under reduced pressure. Diethyl ether (4 ml) and hexane (6 ml) were added to the resultant residue to produce a suspension of the precipitated solid. After filtering the solid, it was subjected to aeration drying to provide the title compound (46.6 mg, 11.7%) as pale yellow powder.

Provenance & Evidence