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

Reaction equation

[OH:1][CH:2]([CH2:20][OH:21])[CH2:3][NH:4][C:5](=[O:19])[C:6]1[C:14]([I:15])=[C:13]([NH2:16])[C:12]([I:17])=[C:8]([C:9]([OH:11])=[O:10])[C:7]=1[I:18].[C:22](OC(=O)C)(=[O:24])[CH3:23].[C:29](OCC)(=[O:31])[CH3:30]>CN(C)C1C=CN=CC=1>[C:22]([O:1][CH:2]([CH2:20][O:21][C:29](=[O:31])[CH3:30])[CH2:3][NH:4][C:5](=[O:19])[C:6]1[C:14]([I:15])=[C:13]([NH2:16])[C:12]([I:17])=[C:8]([C:9]([OH:11])=[O:10])[C:7]=1[I:18])(=[O:24])[CH3:23]

Participants

Procedure

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.