Fenbufen

Fenbufen has been found to be an effective, well-tolerated drug for the treatment of rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis. Fenbufen is prepared by the Friedel-Crafts (aluminum chloride – nitrobenzene) acylation of biphenyl with succinic anhydride. The compound is metabolized in humans first to 4-hydroxy-4-biphenylbutyric acid (tmax 2.5 h) then to 4-biphenyl acetic acid (tmax 7.5 h). Both metabolites are more active than fenbufen itself and circulate for several hours (t1/2 10 h). This slow conversion of fenbufen to active metabolites having relatively long plasma half-lives allows for once a day dosing with this agent.

White Solid

Cinopal,Cyanamid,Italy,1976

muscle relaxant (smooth)

Cyclo-oxygenase inhibitor; analgesic; anti-inflammatory

ChEBI: Fenbufen is a member of biphenyls and a 4-oxo monocarboxylic acid. It has a role as a non-steroidal anti-inflammatory drug.

135 g of aluminum chloride is dissolved in 500 ml of nitrobenzene, the solution being held below 10°C by external cooling. A finely ground mixture of 50 g of succinic anhydride and 75 g of biphenyl is added to the stirred solution, the temperature being held below 10°C. It is then held at room temperature for four days. After pouring the reaction mixture into a solution of 150 ml of concentrated hydrochloric acid in 1 liter of ice water, the nitrobenzene is removed by steam distillation. The solid is collected, dissolved in 4 liters of 3% hot sodium carbonate solution, clarified, and reprecipitated by the addition of excess 6N sulfuric acid solution. The crude product is collected, dried, and recrystallized from ethanol to give the pure subject compound, MP 185°C to 187°C.

Antiinflammatory

Fenbufen belongs to the class of non-steroidal anti-inflammatory drugs, widely used as an antipyretic and analgesic in medical applications. Its mode of action involves the inhibition of cyclooxygenase enzyme and thereby prevents the synthesis of certain prostaglandins.

Clincopal (Lederle, Spain), Lederfen (Lederle, UK), Napanol (Lederle, Japan).

Poison by ingestion,intraperitoneal, and subcutaneous routes. Human systemiceffects by ingestion: cough, sweating, body temperature.An experimental teratogen. Other experimentalreproductive effects. An anti-inflammatory agent. Whenheated to decomposi

[1] Organic Letters, 2016, vol. 18, # 3, p. 504 - 507
[2] Organic Preparations and Procedures International, 1995, vol. 27, # 5, p. 550 - 552
[3] Chemistry Letters, 2015, vol. 44, # 11, p. 1503 - 1505
[4] Organic Process Research and Development, 2004, vol. 8, # 2, p. 291 - 292
[5] Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2000, vol. 39, # 8, p. 614 - 619