Triiodobenzenes derivatives

Ionic contrast media are triiodobenzene derivatives carrying a negative electrical charge, water soluble only as sodium or meglumine (an organic cation similar to glucosamine) salts. 

Nonionic contrast media are neutral water-soluble triiodobenzene derivatives the solubility is provided by hydrophilic groups in the side chains, preferentially hydroxy groups. 

Fig. 1. Triiodobenzene derivatives with low water solubility evaluated as RES-spedfic X-ray contrast agents. Figures in brackets indicate the corresponding reference...

Figure 7 gives a comparison of typical examples of monomeric and dimeric extracellular and hepatocyte-specific triiodobenzene-derived contrast agents. 

With the original protocol, attempted threefold couplings of even a 4-nitro-substituted 1,2,3-triiodobenzene derivative failed.However, under the modified conditions of Jeffery, that is, with a base like potassium carbonate in the presence of a tetrabutylammonium halide, multifold Heck couplings of oligohaloarenes are brought about in very good yields (Schemes 5 and... 

Neudert W and Ropke H, The physico-chemical properties of the disodium salt of adipic acid bis(2,4,6-triiodo-3-carboxyanilide) and other triiodobenzene derivatives, Chem. Ber., 87, 659-667 (1954). Cited in Lemer HH, lodipamide, APDS, 3,333-363 (1974). NB This pJCa value may be a statistically modified composite of and pKs2, since boBi dissociation constants can be expected to be very similar in value. 

An even more challenging approach covers polymeric X-ray contrast agents derived either from linear or from branched backbones, e.g. dendrimers. An overview on this field of research has been published recently [8]. Additionally, the reader is referred to the chapter in this book by Idee et al. covering novel dendrimers with triiodobenzenes as building blocks. 

Selective and stepwise couplings of polyiodobenzene with tenninal acetylenes are also reported. In the course of the synthesis of rigid, benzene-centered, star-like porphyrin arrays, triply coupled derivative 75 has been prepared by Pd/Cu-catalyzed cross-coupling reactions with different terminal acetylenes under normal conditions from 1,3,5-triiodobenzene 74 in a stepwise manner (Scheme 29). ... 

Figure 1. Theoretical (Monte Carlo modelling) and experimental (integrating sphere) (a, c) collimated transmittance T and (h, d) diffuse reflectance visible spectra of the human sclera. MC 1 mm-thickness, 120 nm-mean fihril diameter, 285 nm-mean separation between fibrils, fibril refractive index, = 1.47, and interfibrillar refractive index is under control 1) o = 1-35, 2) 1.37, 3) 1.39, 4) 1.41, 5) 1.43, and 6) 1.45. Experiment The sclera was carefully purified fiom ciliary body and retina, washed, and cut into pieces of area 10x10 mm. (c) Collimated transmittance, sample thickness, 0.6 mm (b) diffusion reflection, sample thickness, 0.7 mm. Samples were measured for different time intervals of administration of Trazograph-60 (x-ray contrast agent - a derivative of 2,4,6-triiodobenzene acid with molecular weight of about 500, n=1.437) in a bath. Spectra 1 were measured 1 min after the samples were immersed in solution, and spectra...

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