Methanol → 4-(2-Fluoro-4-nitrophenoxy)pyridine-2-carboxylic acid methyl ester

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Reaction Conditions

Reaction Steps

4-Chloropyridine-2-carboxylic acid methyl ester (30 g) and 2-fluoro-4-nitrophenol (41.2 g) were dissolved in chlorobenzene (24 ml), followed by stirring under a nitrogen atmosphere at 120° C. for 4 hr. The reaction mixture was allowed to cool down to room temperature, methanol (100 ml) was added, and stirred for 30 min. The solvent was removed under reduced pressure, then the resultant residue was partitioned between ethyl acetate (300 ml) and a 1N aqueous solution of sodium hydroxide (150 ml). The separated organic layer was washed with a 1N aqueous solution of sodium hydroxide (100 ml) and brine (150 ml) and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure, ethanol (200 ml) was added to the resultant residue, followed by stirring for 30 min. The solid was collected by filtration and the filtrate was purified by silica gel column chromatography (YMC, SIL-60-400/230W, eluent; heptane:ethyl acetate=1:1). Fractions containing the target compound were concentrated under reduced pressure, the resultant solid was combined to the solid above to provide 4-(2-fluoro-4-nitrophenoxy)pyridine-2-carboxylic acid methyl ester as a pale brown solid (20.0 g, 40.0%).

Provenance & Evidence