Beilstein J. Org. Chem.2024,20, 2840–2869, doi:10.3762/bjoc.20.240
Peter Langer Institut für Chemie, Universität Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany 10.3762/bjoc.20.240 Abstract Indigo, indirubin, and isoindigo derivatives have been used for centuries as pigments. Since the 1990s, a new aspect of the chemistry of this type of compounds is
their activity against various types of cancer. N-Glycosides of indigo, indirubin, and isoindigo, blue, red, and yellow sugars, turned out to be of special interest because of their high cancerostatic activity and structural novelty. The present article provides an account on the synthesis and
anticancer activity of these compounds.
Keywords: cancerostatic activity; carbohydrates; heterocycles; N-glycosides; indirubin; Introduction
Indigo (1a), known for more than 6000 years and originally produced from indigo plants in India, represents a famous traditional blue pigment which was an expensive
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Graphical Abstract
Scheme 1:
Structures of indigo (1a), indirubin (2a) and isoindigo (3a).
Beilstein J. Org. Chem.2024,20, 228–242, doi:10.3762/bjoc.20.23
derivatives, outline the structural peculiarities, photophysical and photochemical properties of indigo and proceed with the detailed discussion of the photochromic indigo derivatives. Finally, we highlight the photochromism of the structural isomers of indigo (isoindigo and indirubin) and provide an overview
the considerably longer thermal half-lives of Z-22b and Z-23c in comparison to Z-23d [45].
Photochromism of the structural isomers of indigo
The indigo dye has two naturally occurring structural isomers, indirubin (26) and isoindigo (27), which differ in the attachment pattern of the two indole rings
(Figure 14).
Indirubin (26) is a purple colored dye that can be found in Isatis tinctoria and Indigofera tinctoria plants along with indigo and its derivatives or can be obtained as a metabolism product of some bacteria [68]. Given to the wide range of biological activities, including anticancer and anti
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Graphical Abstract
Figure 1:
Precursors used in the synthesis of indigo [4].