4-Nitro-3-trifluoromethylphenol → 4-(4-Nitro-3-trifluoromethylphenoxy)pyridin-2-ylamine

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-amino-4-chloropyridine (2.0 g, 15.6 mmol) in N-methylpyrrolidone (16 ml) were added 5-hydroxy-2-nitrobenzotrifluoride (4.85 g, 23.4 mmol) and diisopropylethylamine (8.15 ml, 46.8 mmol), followed by stirring under a nitrogen atmosphere to heat at 150° C. for 62 hrs. The reaction mixture was cooled down to room temperature and the diisopropylethylamine was evaporated under a reduced pressure. The resultant residue was partitioned between ethyl acetate:tetrahydrofuran=1:1 (300 ml) and a 1 N aqueous solution of sodium hydroxide (100 ml). The organic layer was washed with a 1 N aqueous solution of sodium hydroxide and brine in this order, and dried over anhydrous sodium sulfate. The solvent was evaporated to give a residue, which was then purified by silica gel column chromatography (eluent; heptane/ethyl acetate=1/2, ethyl acetate, then ethyl acetate/methanol=20/1). The crude product was subjected to silica gel filtration (Fuji Silysia NH) The filtrate was concentrated to give a solid, which was then suspended in diethyl ether:hexane=1:1, filtered, and dried under aeration to provide the titled compound (760 mg, 16.3%) as a brown solid.

Provenance & Evidence