Sulfuric Acid → Ketoprofen

Participants

Reaction Steps

α-(3-(1-Phenylethenyl)phenyl)propionic acid (35 g) obtained in Example 5 was dissolved in 250 ml of benzene and 250 ml of water was further added thereto with vigorous stirring to prepare a suspension. Then, 2 liter of 2% aqueous solution of potassium permanganate was dropped little by little over 1.5 hours. After the dropping, stirring was continued for 18 hours at room temperature. After the reaction, it was acidified by adding concentrated sulfuric acid and was treated by adding 35 g of sodium sulfite. After that, 500 ml of water was added and extraction was carried out three times with 150 ml of ether. The ether solution was washed with water and it was extracted three times with 200 ml of 5% aqueous solution of sodium hydroxide. It was then acidified by adding hydrochloric acid and extracted again three times with 150 ml of ether, which was followed by washing with water, drying with anhydrous magnesium sulfate, and filtration. The ether was then removed by reduced-pressure evaporation. Finally, 20 g of α-(3-benzoylphenyl)propionic acid (ketoprofen) was obtained by re-crystallization from benzene/petroleum ether mixture. The melting point and spectrum were the same as those of an authentic sample.

Provenance & Evidence