51484-40-3

Difenax,Zambeletti,Italy,1977

ChEBI: A monocarboxylic acid amide obtained by formal condensation of the carboxy group from biphenyl-4-ylacetic acid with the amino group of 2-aminopyridine. Used for treatment of rheumatoid arthritis.

23 g (0.1 mol) diphenylacetic acid chloride dissolved in 300 cc anhydrous ethyl ether are slowly added dropwise to a solution of 19 g (0.2 mol) 2- aminopyridine in 300 cc anhydrous ethyl ether. The reaction mixture is agitated and the temperature is kept at between 5°C and 10°C with an ice bath. After the addition has been completed, the agitation of the mixture is continued and the temperature is allowed to rise to 20°C to 25°C.
After leaving to stand for a few hours, the gummy precipitate solidifies and becomes filterable. After separating off the precipitate, the ether is evaporated under reduced pressure to a volume of about 100 cc.
The ether is left to stand at a low temperature below 10°C when the remaining portion of the product precipitates and is filtered off and added to the first precipitate. The product thus obtained is thoroughly washed, first in water and then in a solution of sodium bicarbonate, and then again in water. After drying in air, the product is crystallized from anhydrous ethanol or from acetone and water. The analytical data correspond to calculated values. Yield is 18 g; MP 122°C to 124°C.

Antiinflammatory