2-Fluoro-4-nitrophenol → 2-Amino-4-(2-fluoro-4-nitrophenoxy)pyridine

Participants

Reaction Conditions

Reaction Steps

2-Amino-4-chloropyridine (8.00 g) was dissolved in N-methylpyrrolidone (65 ml), and 2-fluoro-4-nitrophenol (19.55 g) and N,N-diisopropylethylamine (43.36 ml) were added thereto, followed by stirring at 160° C. for 41 hr. The reaction mixture was allowed to cool down to room temperature, and was partitioned between ethyl acetate-tetrahydrofuran (1:1) and a 2N aqueous solution of sodium hydroxide. The organic layer was washed with water and brine in this order. The aqueous layer was re-extracted with ethyl acetate, and the combined organic layer was dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure, the residue was purified by silica gel column chromatography (eluent; hexane:ethyl acetate=1:2, then ethyl acetate). Fractions containing the target compound were concentrated, and crystals were precipitated by addition of ethyl acetate to the residue. The crystals were collected by filtration and dried under aeration to provide the titled compound as opalescent crystals (3.02 g, 20%).

Provenance & Evidence