Dimethylformamide → 2,4,6-triiodo-5-isocyanato-N,N,N'-trimethylisophthalamide

Beteiligte Stoffe

Reaktionsschritte

To glucosamine (1.97 g., 0.011 mole) and potassium carbonate (4.14 g.; 0.03 mole) in dimethylformamide (49 ml.) was added dropwise (required about 5 minutes) 3-acetamido-2,4,6-triiodo-5-isocyanato-N-methylbenzamide (III; 6.11 g.; 0.01 mole) dissolved in dimethylformamide (20 ml.). After being stirred overnight, the reaction mixture was filtered and concentrated in vacuo. The residue was dissolved in water (64 ml.) and the aqueous solution was adjusted to pH 1 with concentrated hydrochloric acid. The solution was extracted with aqueous 90% phenol (4×25 ml.). The combined, phenolic layers were washed with water (4×25 ml.), diluted with ether (300 ml.) and extracted with water (4×25 ml.). The combined aqueous layers were washed with chloroform-isopropyl alcohol (3:1; 5×100 ml., contact time 15 min.), treated with "Darco G-60" (0.25 g.) overnight, and evaporated under reduced pressure at 40° C. (water bath), to give 3-acetamido-5-{3-[2-D-gluco-2-deoxy-3,4,5,6-tetrahydroxy-1-oxohexyl]ureido}-2,4,6-triiodo-N-methylbenzamide (IV) as faint-yellow foam, 5.08 g. (64.5%), m.p. 186°-251° C. (dec.). The infrared and nuclear magnetic resonance spectra were consistent with the assigned structure. The material was homogeneous by thin-layer chromatography (chloroform-methanol-triethylamine, 65:35:5) and the aqueous solubility was determined to be 18-20% (w/v).

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