3,5-Diiodo-4-pyridone-1-acetic Acid is used in contrast media.
ChEBI: Diodone is a 4-pyridone in which the pyridone is iodo-substituted at C-3 and -5 and has a carboxymethyl substituent on nitrogen; used as a radiocontrast agent urography. It has a role as a radioopaque medium. It is a member of 4-pyridones, a monocarboxylic acid and an organoiodine compound.
2 mol of pyridine are reacted with thionyl chloride to give 4-pyridyl-pyridinium
chloride. The last one is transformed into 4-1H-pyridone by adding of water at
150°C. Then it is added to 1 mol of iodomonochloride (ICl) to give 3,5-
diidopyridone. It is converted in 3.5-diiodo-4-pyridone-N-acetic acid by
addition of chloroacetic acid and sodium hydrate. 1 mol of 3.5-diiodo-4-
pyridone-N-acetic acid is dissolved in a solution of 1 mol of diethanolamine in
60 ml of water while heating. The solution is made up to 100 ml with water.
After evaporating the solution and recrystallizing, the salt is obtained in the
form of white crystals. MP: 153°C.
