Indigo red

Indigo red is found in the Indian and Guatemala products to the extent of 1-8% and in that from Java in much larger quantity the amount of indigo brown may reach 5%, and that of indigo gum 4%. 

Indigo red forms a vat and a sulphonic acid, both capable of dyeing. The shades produced in the vat are noteworthy for their extreme fastness to light. 

However, only indigo red is formed via an aldol-type condensation shown in Fig. lb. Carbonyl carbon a (see Fig. 1) is not attacked by the carbanion because it is substantially deactivated by an amide resonance with the adjacent NH group ... 

Therefore attack by the carbanion takes place at carbonyl carbon b, which yields indigo red upon the loss of H2O. 

Synthesis After A. von Baeyer achieved the first synthesis of I. in 1878 and the exact structure was elucidated in 1883, further syntheses of I. were developed, the best of which was that by Heumann in 1890. Like natural 1., synthetic I. contains the isomeric indigo red, the content of the latter ranges from 2-4% in Bengal I. to 15% in Java I. The biosynthesis proceeds from indole and/or L-tryptophan and has not been completely clarified . ... 

Tryptophan reacts with chlorine dioxide (195) to give a mixture containing isatin, indoxyl, indigo red, and other substances (64). Histidine also reacts (195), but the products have not been characterized. 

S -Tetraphenyl-thio-indigo ) red. with alkali acetone 300 9 no detailed A/-data Br 16 ... 

Indigo red org chem Ci H 10O2N2 A red isomer of indigo obtained in the manufacture of indigo. Also known as indirubin. in-da-go red ... 

Indirect effect phys chem A chemical effect of ionizing radiation on a dilute solution caused by the interaction of solute molecules with highly reactive transient molecules or ions formed by reaction of the radiation with the solvent., in-da rekt i fekt Indirubin See indigo red., in-da rii-ban )... 

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