Pigment derivative

BenZimidaZolones. This class of pigments derives its name from 5-aminobenzimidazolone/Pj5 -2J-< 7 which upon reaction with diketene or 2-hydtoxy-3-naphthoyl chloride leads to compounds which can be coupled with a variety of diazotized amines. 

Orga.nic Colora.nts. The importance of coal-tar colorants cannot be overemphasized. The cosmetic industry, in cooperation with the FDA, has spent a great deal of time and money in efforts to estabUsh the safety of these dyes (see Colorants for food, drugs, cosmetics, and medical devices). Contamination, especially by heavy metals, and other impurities arising from the synthesis of permitted dyes are stricdy controlled. Despite this effort, the number of usable organic dyes and of pigments derived from them has been drastically curtailed by regulatory action. 

Pigments derived from pyrazolones include Hansa Yellow R, l-phenyl-3-methyl-4-[(2,5-dichlorophenyl)azo]-5-hydroxypyrazole and Pigment Chrome Yellow, 1-phenyl-3-methyl-4-[(o-tolylazo]-5-hydroxypyrazole, as examples of monoazo compounds. 

Pterins — These are pigments derived from pteridine skeletons. All natural pterins are 2-amino-4-hydroxypteridines bearing various substituents at Cg and C7 and having different oxidation states of N5 and Ng. 

Sava, V.M. et al., Isolation and characterization of melanic pigments derived from tea and tea polyphenols, Food Chem., 73, 177, 2001. 

Escribano-Bailon, T. et al.. Color and stability of pigments derived from the acetaldehyde-mediated condensation between malvidin 3-O-glucoside and (-t-)-catechin, J. Agric. Food Chem., 49, 1213, 2001. 

Hajjaj, H. et ah. Production and identification of N-glucosylrubropunctamine and N-glucosyhnonascorubramine from Monascus ruber and occurrence of electron donor-acceptor complexes in these pigments, Appl Environ. Microbiol, 63, 2671, 1997. Jung, H. et ah. Color characteristics of Monascus pigments derived by fermentation with various amino acids, J. Agric. Food Chem., 51, 1302, 2003. 

Hayasaka, Y. and Asenstorfer, R.E., Screening for potential pigments derived from anthocyanins in red wine using nanoelectrospray tandem mass spectrometry, J. Agric. Food Chem., 50, 756, 2002. 

These are the only ranges of precursor products in the Colour Index that are still commercially significant. Azoic dyes have a close formal relationship to those monoazo pigments derived from BON acid or from acetoacetanilides (section 2.3.1) and some are chemically identical with them, although they are used in a totally different way. Azoic components are applied to produce insoluble azo dyes within the textile substrate, which is almost always cotton. Corresponding azoic components for the dyeing of cellulose acetate, triacetate and polyester fibres were once commercially important, but are now obsolete because of environmental hazards and the time-consuming application procedure. 

These pigments derive their name from 2-hydroxy-3-naphthoic acid, which is used as a general coupling component for the entire group. The compound is also known as beta-oxynaphthoic acid (BONA). 

Most pigments derived from vat dyes are structurally based on anthraquinone derivatives such as indanthrone, flavanthrone, pyranthrone, or dibromoan-thanthrone. There are other polycyclic pigments which may be used directly in the form in which they are manufactured. This includes derivatives of naphthalene and perylene tetracarboxylic acid, dioxazine (Carbazole Violet), and tetrachloro-thioindigo. Quinacridone pigments, which were first introduced in 1958, and recently DPP pigments have been added to the series. 

In this section a number of polycyclic pigments are discussed which have been used for a long time as vat dyes for textile fibers. Heading the list are perylene, perinone, and thioindigo pigments, as well as pigments derived from anthraquinone. 

As a group, these pigments include derivatives of 1-aminoanthraquinone, which is the only derivative of the possible parent compounds which has stimulated commercial interest. While the synthetic routes to the pigment derivatives are found under the respective pigments, the pathway for 1-aminoanthraquinone will be described separately. 

Imports of 3,3 -dichlorobenzidine base and salts were 1.1 million poimds in 1983, while pigments derived from 3,3 -dichlorobenzidine were about 129,000 pounds in 1983 (USITC 1984b). 

No uses of 3,3 -dichlorobenzidine in commonplace consumer products are known. In the past, the general public may have been exposed to minute amounts of 3,3 -dichlorobenzidine during the use of pressurized spray containers of paints, lacquers, and enamels containing traces of benzidine yellow, a pigment derived... 

Nonradioactive methods determining isolated conjugated azodiptjrrole Conjugated azo pigment, derived from syn- GTE. Versatile TLC can be applied thetic BC, is determined photometrically after its chromatographic isolation ... 

Radioactive conjugated azo pigment, derived from conjugated bilirubin, is counted, after separation from other labeled compounds (Table... 

Spectroscopy and Physical Chemistry of Retinal and Visual Pigments. Several reviews and symposium proceedings discuss the spectroscopic, photochemical, or physicochemical properties of retinal and related compounds, and of natural and model visual pigments derived from them. " " In addition, many papers have been published dealing with specific aspects of the spectroscopy (u.v., n.m.r., resonance Raman) of retinals and rhodopsins" or with aspects of the photochemistry and physical chemistry of retinal derivatives which may be relevant to the functioning of rhodopsin and other visual pigments. The bacterial purple... 

Determination Of Residual DCB In Diarylide Yellow. Diary-lide yellow is a widely used pigment derived from DCB. The purpose of this study was to determine residual DCB in a lot of the commercial pigment being used in animal feeding experiments. 

Blue ultramarine-blue from over the sea - is the name which European artists of the Middle Ages gave to the pigment derived from lapis lazuli, a semiprecious stone imported mainly from Afghanistan. Ultramarine was the supreme blue of medieval times, but eventually it became scarce and very expensive. 

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