2-Aminophenol → 2-(4-Chloro-2-fluoronitrobenzen-5-yl)benzoxazole

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Reaction Steps

2-Chloro-4-fluoro-5-nitrobenzoic acid (4.00 g, 18.2 mmol), 2-aminophenol (2.09 g, 20.1 mmol), CHCl3 (80 mL), and WSC (3.84 g, 20.0 mmol) were added together and stirred at room temperature for 2 hours. Water was added, and this was extracted with chloroform/acetone (3:1). After the organic layer obtained was dried over anhydrous sodium sulfate, it was filtered and concentrated. To a toluene (80 mL) solution of the solid obtained was added p-toluenesulfonic acid monohydrate (0.18 g, 1.8 mmol), and this was heated to reflux for 40 hours. After the reaction solution was concentrated, water was added, and the precipitated crystals were filtered, and after being washed with water were dried to yield the title compound (1.40 g, 26% yield) as yellowish-brown crystals.

Provenance & Evidence