A cyclodextrin-based molecular reactor to template the formation of indigoid dyes

N,N′-Bis(6A-deoxy-β-cyclodextrin-6A-yl)urea behaves as a molecular reactor to bias competing reactions of indoxyl anion and isatin-5-sulfonate in water, to give indigo and indirubin-5′-sulfonate. It appears that the cyclodextrin dimer increases the relative reactivity of the isatin-5-sulfonate, by selectively complexing the reactive form. The molecular host also aligns the isatinsulfonate with indoxyl anion to favour production of indirubin-5′-sulfonate, with the result that the ratio of indigo and indirubin-5′-sulfonate produced is altered by a factor of at least 3500, without a substantial loss of yield.

[1]  S. Lincoln,et al.  Modified Cyclodextrins: Scaffolds and Templates for Supramolecular Chemistry , 1999 .

[2]  R. Breslow,et al.  Biomimetic Reactions Catalyzed by Cyclodextrins and Their Derivatives. , 1998, Chemical reviews.

[3]  S. Hamai,et al.  Inclusion effects of cyclomaltohexa- and heptaose (α- and β-cyclodextrins) on the acidities of several phenol derivatives , 1997 .

[4]  M. Komiyama,et al.  Selective syntheses using cyclodextrin as catalyst. 1. Control of orientation in the attack of dichlorocarbene at phenolates , 1983 .

[5]  Ronald Breslow,et al.  Biomimetic Chemistry and Artificial Enzymes: Catalysis by Design , 1995 .

[6]  S. Lincoln,et al.  Metallocyclodextrin catalysts for hydrolysis of phosphate triesters , 2002 .

[7]  M. L. Bender,et al.  Acceleration of phenyl ester cleavage by cycloamyloses. A model for enzymic specificity , 1967 .

[8]  S. Lincoln,et al.  Cyclodextrin and termethylated cyclodextrin complexation of aromatic carboxylic acids and their conjugate bases in aqueous solution. The effect of size, hydrophobicity and charge , 1995 .

[9]  M. L. Bender,et al.  The mechanism of the cycloamylose-accelerated cleavage of phenyl esters , 1967 .

[10]  R. Breslow,et al.  Selective aromatic substitution by hydrophobic binding of a substrate to a simple cyclodextrin catalyst , 1971 .

[11]  R. Breslow,et al.  Selective aromatic substitution within a cyclodextrin mixed complex , 1969 .

[12]  R. Breslow,et al.  CATALYSIS OF AN INTRAMOLECULAR ALDOL CONDENSATION BY IMIDAZOLE-BEARING CYCLODEXTRINS , 1994 .

[13]  Susan E. Brown,et al.  Substituent effects and chiral discrimination in the complexation of benzoic, 4-methylbenzoic and (RS)-2-phenylpropanoic acids and their conjugate bases by β-cyclodextrin and 6A-amino-6A-deoxy-β-cyclodextrin in aqueous solution: potentiometric titration and 1H nuclear magnetic resonance spectroscopi , 1993 .

[14]  H. Kohn,et al.  Methylated cyclodextrin and a cyclodextrin polymer as catalysts in selective anisole chlorination , 1976 .

[15]  T. Kurucsev,et al.  Complexation of Methyl Orange and Tropaeolin 000 No. 2 by β-cyclodextrin dimers , 1997 .

[16]  H. Henze,et al.  Utilization of Isoamyl α-Methoxyethyl Ketone in the Pfitzinger Synthesis1 , 1944 .