1013.2 g 3-amino-2,4,6-triiodobenzoyl chloride are dissolved in a minimum
amount of hot dioxane and caused to flow into 700.6 g molten methyl β-
anilinopropionate with stirring. After the ensuing exothermic reaction has
gradually terminated the reaction mixture is heated on a steam bath for about
3 h and while boiling hot has then methanol and methanolic 3 N HCl added
thereto, where after it is cooled. The precipitated solids are separated and
washed with ether. 953.0 g methyl β-N-(3-amino-2,4,6-triiodobenzoyl)-
phenylaminopropionate are obtained having a melting paint of 156°-157°C.
Yield 74.2% of theory
The methyl ester may be precipitated as the free acid by dissolving in
dioxane, addition of 3.15 N methanolic sodium hydroxide solution, pouring the
resulting reaction mixture in water, and acidulating the solution with 6 N HCl.
After separation and drying, 553.6 g β-N-(3-amino-2,4,6-triiodobenzoyl)-
phenylaminopropionic acid having a melting point of 133°-134.5°C are
obtained from 571.0 g methyl ester. Overall yield 73.46% of theory.
