Smiles Rearrangement in the Synthesis of Di- and Triiodinated 5- (Acylamino)-1,3-Benzenedicarboxamides

Both the number and the position of iodine atoms on the aromatic ring of polyiodinated N,N'-bis(2,3- dihydroxypropyl)-5-(2-methylamino-2-oxoethoxy)-1,3-benzenedicarboxamides are crucial to define the structure of the product obtained by treatment with aqueous NaOH. The 2,6-diiodo and the 2,4,6-triiodo derivatives give the correspond- ing Smiles rearrangement products in 77 and 96% yields, respectively. Conversely, under the same conditions, the 2,4- diiodo isomer predominantly undergoes hydrolysis of the phenoxyacetamide moiety.