5-Amino-N,N'-bis(2,3-dihydroxypropyl)-2,4,6-triiodo-1,3-benzenedicarboxamide Tetraacetate → N,N'-bis[2,3-bis(acetyloxy)propyl]-5-[(2,5-dibromo-1-oxopentyl)amino]-2,4,6-triiodo-1,3-benzenedicarboxamide

Participants

Reaction Steps

2,5-Dibromopentanoyl bromide (11 g, 34 mmol ) was added dropwise to a stirred solution of N,N'-bis[2,3bis(acetyloxy)propyl]-5-amino-2,4,6-triiodo-1,3-benzenedicarboxamide (23.0 g, 26.3 mmol) in N,N-dimethylacetamide (240 ml) at 0°. After the addition, the reaction mixture was stirred at 0° for 1 hour, and then at room temperature for 20 hours. The solvent was removed in vacuo at 45° and the resulting solid was dissolved in ethyl acetate (400 ml). The organic layer was washed with saturated aqueous sodium bicarbonate (1×70 ml), water (1×70 ml) and saturated sodium chloride (1×70 ml). After drying over magnesium sulfate, the solvent was removed in vacuo to obtain a yellow residue (28 g). Purification by column chromatography over silica gel furnished pure N,N'-bis[2,3-bis(acetyloxy)propyl]-5-[(2,5-dibromo-1-oxopentyl)amino]-2,4,6-triiodo-1,3-benzenedicarboxamide as an off-white crystalline compound (20.2 g, yield 69%).

Provenance & Evidence