Indirubin-5-sulfonate

Figure 3.5 Competing reactions of indoxyl and isatin/isatin-5-sulfonate to give indigo and indirubin/indirubin-5 -sulfonate...

Figure 3.6 Illustrations of a urea-linked ji-cyclodextrin dimer a) complexing Tropaeolin 000 No. 2, and matching b) the orientation required for binding indirubin/indirubin-5 -sulfonate, and therefore c) the orientation required to template the reaction of indoxyl with isatin/isatin-5-sulfonate...

In the present case, this was accomplished with isatin-5-sulfonate instead of isatin, using the urea-Unked cyclodextrin dimer to alter the ratio of formation of indigo, through oxidative dimerisation of indoxyl, to indirubin-5 -sulfonate, from indoxyl and the isatin-sulfonate (Figure 3.5). The isatinsulfonate exists in solution in equilibrium with its hydrate, which deprotonates with a pA a of 9.55 to give the corresponding anion... 

Table 3.1 Affects of cyclodextrins on the percentage yields of indigo and a) indirubin or b) indIrubin-S -sulfonate, formed under otherwise identical conditions ...

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