N,N'-bis-[2-acetyloxy-1-(acetyloxymethyl)ethyl]-5-[3-bromo-2-oxo-1-pyrrolidinyl]-2,4,6-triiodo-1,3-benzenedicarboxamide → N,N'-bis-[2-acetyloxy-1-(acetyloxymethyl)ethyl]-5-[3-acetyloxy-2-oxo-1-pyrrolidinyl]-2,4,6-triiodo-1,3-benzenedicarboxamide

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Reaction Steps

N,N'-bis-[2-acetyloxy-1-(acetyloxymethyl)ethyl]-5-[3-bromo-2-oxo-1-pyrrolidinyl]-2,4,6-triiodo-1,3-benzenedicarboxamide (4.00 g, 3.92 mmol) of example 4a was dissolved in glacial acetic acid (40 ml) and treated with silver acetate (3.25 g, 19.50 mmol) at 133°-135° for 26 hours under a nitrogen atmosphere. The suspended solids were filtered off and the solvent was removed in vacuo. The resulting crude residue was treated with acetic anhydride (30 ml) and pyridine (42 ml), after which the volatile components were completely removed Under high vacuum. The resulting product was purified by silica gel flash chromatography to obtain N,N'-bis-[2-acetyloxy-1-(acetyloxymethyl)ethyl]-5-[3-acetyloxy-2-oxo-1-pyrrolidinyl]-2,4,6-triiodo-1,3-benzenedicarboxamide as a pale orange foam (3.20 g, 82% yield).

Provenance & Evidence