4-Fluoroaniline → 2-(2-(4-Fluorophenyl)aminoanilin-5-yl)benzoxazole

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Reaction Steps

To a suspension of 2-(4-fluoro-3-nitrophenyl)benzoxazole (see Working Example 15-2) (300 mg, 1.16 mmol) in ethanol (5 mL) was added sodium hydrogen carbonate (195 mg, 2.32 mmol) and 4-fluoroaniline (322 mg, 2.90 mmol), and this was heated to reflux with stirring for 4 hours. After the reaction was complete, this was cooled to room temperature, water was added, and this was extracted with chloroform. After the organic layer obtained was dried over anhydrous sodium sulfate, it was filtered and concentrated. The crystals obtained were added to a tetrahydrofuran (5 mL) solution containing 10% palladium-carbon (50 mg), a hydrogen atmosphere was substituted in the flask, and this was stirred at room temperature for 4 hours. After the reaction was complete, this was filtered through Celite and the filtrate was concentrated. The residue obtained was purified by silica gel column chromatography to yield the title compound (40.0 mg, 11% yield) as brown crystals.

Provenance & Evidence