16712-16-6

70-11-1

20662-89-9

The general procedure for synthesizing 4-phenyloxazole from the compound (CAS:16712-16-6) and 2-bromoacetophenone is as follows: referring to the method of Example 12, benzoyl bromide (4 g, 20.1 mmol) was dissolved in formic acid with ammonium formate (44 g, 70.35 mmol). The acid solution (20 mL) was heated to reflux for 5 hours. After completion of the reaction, the dark red mixture was cooled to room temperature, diluted with water and alkalized with dilute sodium hydroxide solution. Subsequently, the mixture was extracted with ethyl acetate (three times), the organic layers were combined and washed sequentially with water and brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure to remove the solvent. The residue was purified by column chromatography on silica gel (60-120 mesh) with 20% ethyl acetate-petroleum ether as eluent to give the final 4-phenyloxazole (1 g, 34% yield), the product was a light yellow oil and cured at -20 °C.