Indigoid Color

Beside indigo itself, the indigoid colorant thioindigo and its derivatives are also important vat dyes, but because of the low affinity of vatted thioindigo dyes for the fiber, these dyes are used mainly in textile printing. 

Classification Indigoid color Empirical CisH8N2Na208S2 Formula C16H8N2O8S2 2Na Properties M.w. 466.35... 

Classification Indigoid color Empincal C16H10N2O Properties M.w. 246.28 Toxicology LD50 (oral, mouse) > 32 g/kg, (IP, mouse) 2200 mg/kg irritant mutagen TSCA... 

CAS 2379-74-0 EINECS/ELINCS 219-163-6 Synonyms 6-Chloro-2-(6-chloro-4-methyl-3-oxobenzo [b] thien-2(3H)-ylidene)-4-methylbenzo [b] thiophen-3(2H)-one Cl 73360 Helindone pink CN Vat red 1 Classification Indigoid color Empirical C i8Flio i202S2 Properties Bluish pink m.w. 393.30 Toxicology TSCA listed Uses Colorant in cosmetics, pharmaceutical orals... 

There are three color additives of the indigoid type, including D C Blue No. 6 (35) (an insoluble pigment), FD C Blue No. 2 (2) (the water-soluble disodium sulfonate derivative of indigo), and D C Red No. 30 (23) (an insoluble thioindigoid). AH are related to indigo [482-89-3] which has stmcture (35) (Fig. 3). 

In context with the formation of peraminosubstituted 1,4,5,8-tetraazaful-valenes of type 85 it must be mentioned that the bis-vinylogous compounds 94 can be easily prepared by reaction of acetamidine with bisimidoylchlo-rides derived from oxalic acid (96S1302). In the course of a complex reaction a cyclic ketene aminal was produced it immediately underwent an oxidative dimerization to yield deeply colored TAFs. Tlieir high chemical stability can be compared with that of indigoid dyes and manifests itself, for example, by the fact that they are soluble in hot concentrated sulfuric acid without decomposition. Tire same type of fulvalene is also available by cy-... 

Anthraquinone leuco dyes are widely known as vat dyes.10 Vat dyes possess extensively conjugated aromatic systems containing two or more carbonyl groups, e.g., anthraquinone, indigoid chromophores. The colored form of vat dyes are insoluble in water. The dyes are applied by a process whereby the dye is converted to the reduced form (leuco dye) which is soluble in water and can penetrate into a cellulosic fiber. On exposure to the atmosphere the leuco form is oxidized to the original quinoid form which then precipitates as an aggregate. Vat dyes generally have excellent chemical and photochemical stability. 

Indigenous biocontrol species, 13 347 Indigo, color, 7 332 Indigoid dyes, 9 256... 

Anthraquinone acid, disperse, basic and reactive dyes 280 Polycyclic vat dyes 294 Indigoid and thioindigoid dyes 316 Sulphur and thiazole dyes 321 Diarylmethane and triarylmethane dyes 327 Miscellaneous colorants 344 References 353... 

The leuco esters of vat dyes are anthraquinoid or indigoid vat dyes (Section 3.4) that have been made water soluble by reduction and esterification of the hydroxyl groups with sulfuric acid. These dyes are used mainly for dyeing high-quality articles of cellulose fibers in light colors and polyester-cellulose blends to moderate depths of shade [58], [59, p. 568],... 

From ancient times, mankind was enchanted by the marvelous colors arising from the treatment of cloth with the natural dyes extracted from various animals or plants. As early as the 13th century B.C., Phoenicians knew how to manufacture indigoid dyes (Tyrian purple) from the secretions of certain Mediterranean Sea mollusks. To produce 1 gram of the dye, 10000 animals were required for a lengthy and laborious procedure. Its price was up to 10-20 times its weight in gold. 

Comments Indigo carmine is an indigoid dye used to color oral and topical pharmaceutical preparations. It is used with yellow colors to produce green colors. Indigo carmine is also used to color nylon surgical sutures and is used diagnostically as a 0.8% w/v injection. 

The synthetic food colorants, according to their chemical structure, belong to mono-, di-, and trisazo, triarylmethane, xanthene, quinoline, and indigoid. They can also be divided into water-soluble, oil-soluble, insoluble (pigment), and surface marking colors. 

Beutner, S., Bloedom, B., Frixel, S., Blanco, L, Hoffmann, T., Martin, H., Mayer, B., Noack, P, Ruck, C., Schmidt, M., Schulke, L, Sell, S., Ernst, H., Haremza, S., Seybold, G., Sies, H., Stahl, W., and Walsh, R. 2001. Quantitative assessment of antioxidant properties of natural colorants and phytochemicals carotenoids, flavonoids, phenols and indigoids. The role of P- carotene in antioxidants functions, J. Sci. Food Agric., 81, 559. 

Beutner, S. et al. Quantitative assessment of antioxidant properties of natural colorants and phytochemicals carotenoids, flavonoids, phenols and indigoids the role of P-carotene in antioxidant functions, J. Set Food Agric., 81, 559,2001. 

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