Acetic Anhydride → RAC-5-amino-N-(2,3-diacetoxypropyl)-2,4,6-triiodoisophthalamic acid

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Reaction Steps

300 g (0.475 mol) of 5-amino-2,4,6-triiodoisophthalic acid mono-(2,3-dihydroxy-propyl) amide is suspended in 1.4 liter of ethyl acetate, mixed with 178.07 g (1.74 mol) of acetic anhydride and 5.7 g (47.5 mmol) of 4-dimethylaminopyridine and the mixture is heated to boiling. The suspension changes into a solution from which the product quickly crystallizes out in the boiling heat. The acetylation is completed after 1 hour. The excess acetic anhydride is reacted to ethyl acetate by addition of ethanol, cooled to room temperature, the crystallizate is suctioned off, washed with ethyl acetate and dried in a vacuum at 50° C. The yield is 300.2 g (0.42 mol)=88.4% of theory.

Provenance & Evidence