p-Toluenesulfonic acid monohydrate → 2-(4-Fluoro-3-nitrophenyl)benzoxazole

Participants

Reaction Steps

To a suspension of 4-fluoro-N-(2-hydroxyphenyl)-3-nitrobenzanilide (see Working Example 15-1) (2.00 g, 7.24 mmol) in toluene (50 mL) was added p-toluenesulfonic acid monohydrate (2.07 g, 10.9 mmol), and this was stirred and heated to reflux for 4 hours. After the reaction was complete, this was cooled to room temperature, and after the solvent was distilled off, saturated aqueous sodium hydrogen carbonate solution was added and this was stirred for 10 minutes at room temperature. The precipitated crystals were filtered off, and after washing with toluene the crystals were dried to yield the title compound (1.30 g, 70% yield) as yellow crystals.

Provenance & Evidence