Anthraquinones purpurin

Some anthraquinones isolated from Rubia tinctorum are believed to be artefacts for example the anthraquinones which show the presence of a 2-methoxymethyl or 2-ethoxymethyl group. These anthraquinones have been formed during the extraction of lucidin with boiling methanol or ethanol [4,68,97]. According to Schweppe the anthraquinones purpurin (1,2,4-trihydroxy anthraquinone) and purpuroxanthin (1,3-dihydroxy-anthaquinone) are formed from respectively pseudopurpurin (3-carboxy-1,2,4-trihydroxyanthraquinone) and munjistin (2-carboxy-l,3-dihydroxy-anthraquinone) during drying of the roots [3]. Some anthraquinones were only isolated once from Rubia tinctorum. It is thus doubtful whether these... 

For the detection of boric acid, the best hydroxyanthraquinones are l,2-dihydroxyanthraquinone-3-sulfonic acid (alizarin S) 1,2,4-trihydroxy-anthraquinone(purpurin) l,2,5,8-tetrahydroxyanthraquinone(quinali2arin). 

Acid—mordant dyes have characteristics similar to those of acid dyes which have a relatively low molecular weight, anionic substituents, and an affinity to polyamide fibers and mordant dyes. In general, brilliant shades caimot be obtained by acid—mordant dyes because they are used as their chromium mordant by treatment with dichromate in the course of the dyeing procedure. However, because of their excellent fastness for light and wet treatment, they are predominandy used to dye wool in heavy shades (navy blue, brown, and black). In terms of chemical constitution, most of the acid—mordant dyes are azo dyes some are triphenyhnethane dyes and very few anthraquinone dyes are used in this area. Cl Mordant Black 13 [1324-21 -6] (183) (Cl 63615) is one of the few examples of currentiy produced anthraquinone acid—mordant dyes. It is prepared by condensation of purpurin with aniline in the presence of boric acid, followed by sulfonation and finally by conversion to the sodium salt (146,147). 

Statistical evaluation of HPLC UV MS[19] and CE UV MS[20] methods proves that MS detection of anthraquinone dyes is more sensitive than UV, especially in the case of chromatographic analysis of laccaic acids (almost 20 times) and purpurin (almost 40 times). However, detection limits of HPLC ESI MS determination of alizarin and purpurin (0.03 gg ml ) are about 20 times lower than those of CE ESI MS (0.52 0.58 gg ml x). 

In a DTA study of 14 anthraquinone dyes, most had high flash points (225-335°C) and ignition points (320-375°C). Purpurin dianilide [107528-40-5] was exceptional with the much lower values of 110 and 155°C, respectively. 

N.A. Rubia tinctorum L. Anthraquinone derivatives, ruberythric acid, alzarin, purpurin, indoid, asperuloside, resin, calcium.99 Treat kidney and bladder stones. 

Quinone Colors depend on mordant and pH 1. benzoquinone 2. naphthaquinone 3. anthraquinone Carthamine Juglone Alizarin Purpurin Walnut or butternut (Juglans sp.) Rubiaceae family Sorrel (Rumex sp.) Poligonaceae family Forms lake with mordant For 3. pH >7 -> violet-blue pH < 7-> yellow-red AL rose-red Ca bluish-red Zn red-violet Fe black-violet Cr=red brown... 

In a DTA study of 14 anthraquinone dyes, most had high flash points (225—335°C) and ignition points (320—375°C). Purpurin dianilide [107528-40-5] was exceptional with the much lower values of 110 and 155°C, respectively [1]. A similar study of indigo type dyes and vat solubilised modifications is reported. The basic dyes decompose over 350°C, destabilised to around 200°C for solubilised dyes. The relation between functional groups, structure and flammability is discussed [2]. Sulfonyl azides have been employed for attachment of reactive dyes, it is claimed they are safer used in supercritical carbon dioxide than in water [3]. 

Peroxidases purified from plants have also been used for the degradation of dyes. Purified peroxidase of Saccharum spontaneum leaf could degrade a variety of dyes ranging from the 70% to 100% in 1 h [144]. A peroxidase of Ipomeapalmata was also able to transform different dyes, but less effectively. A peroxidase purified from Senna angustifolia oxidized alizarin and purpurin anthraquinones efficiently to produce the respective bianthraquinones the same reaction was catalyzed by horseradish peroxidase [145],... 

Anthraquinones The Oj Pile). Alizarin (1,2-dihydroxyanthraquinone) is the orange-red compound of Rubia tinctorum (madder) (Rubiaceae), a longstanding dyestuff in human history. A range of anthraquinones are variously cathartic, antimicrobial and cytotoxic. A variety of anthraquinones are protein kinase inhibitors including alizarin, chrysazin, damnacanthal, emodin and purpurin. 

From two disulphonic adds of anthraquinone, two trioxyanthra-quinones, flavo- and anthra-purpurin, are prepared in a manner analogous to that by which alizarin is obtained from the monosulphonic acid. 

Several anthraquinone derivatives have been suggested for the spectrophotometric determination of germanium, namely quinalizarin (extraction of the complex with chloroform in the presence of diphenylguanidine), Purpurin (1,2,4-trihydroxyanthraquinone) [52], and Alizarin Complexone [53]. 

Further examples of the sulfonation of phenols by this method are the preparation of l,4-dihydroxyanthraquinone-2-sulfonic acid from quinazirin189 and of 1,3,4-trihydroxy-anthraquinone-2-sulfonic acid from purpurin.190... 

Recently the separation of 10 anthraquinone aglycones and two glycosides from Rheum by capillary electrophoresis was described [88] and compared with an HPLC separation. Two of the investigated aglycones also occur in madder alizarin and purpurin. Because all of the anthraquinones can be charged by means of complexation with a borate buffer, capillary zone electrophoresis (CZE) was chosen as separation mode. The separations were carried out with a 90 cm x 75 pm fused silica capillary. The detection window was located at 80 cm. Dectection occurred at 260 nm. The voltage was 23 kV and the temperature 20°C. The injection was pressure controlled (1.2 sec at 200 mbar). The total run time was 39 min (compared to 63 min for gradient RP-HPLC for the same set of test substances). 

After the first isolation of alizarin a lot of other anthraquinones were isolated from Rubia tinctorum for example purpurin, munjistin, rubiadin, pseudopurpurin, nordamnacanthal, lucidin, xanthopurpurin and anthra-gallol. 

The roots of Rubia tinctorum have been used for dyeing textiles in many parts of the world since ancient times. Madder was widely cultivated in Western Europe for the dye industry until the beginning of the twentieth century. Rubia tinctorum contains useful anthraquinone mordant dyes. Dried roots of madder contain the hydroxy anthraquinones alizarin, pseudopurpurin, rubiadin, purpurin, purpuroxanthin and some minor anthraquinones. Anthraquinone derivatives are good mordant dyes if they satisfy the following conditions ... 

Graebe (an assistant) and C. Liebermann (a student) in Baeyer s laboratory reduced alizarin to anthraquinone by Baeyer s method of heating with zinc dust, and thus established that alizarin is a derivative of anthracene, and not of naphthalene as had been thought. They proposed a formula for anthracene and synthesised alizarin from anthraquinone. This led to the synthetic alizarin industry, and the decline of natural madder as a dye. The other colour in madder, purpurin, was synthesised by oxidising alizarin by F. de Lalande. Behr and van Dorp obtained anthraquinone by heating o-benzoylbenzoic acid with phosphoric oxide, when ring-closure occurs. They discovered 1 8-naphthalenedicarboxylic acid. ... 

Before the introduction of synthetic anthraquinone derivatives, natural anthraquinone dyes have been used for centuries. Apart from alizarin, madder also contains e.g. purpurin, pseudopurpurin, rubiadin and munjistin. 

Red Colorants. The most important class of pre-Perkin colorants, from the coordination chemistry point of view, is the red colorants. All of the major red colorants, whether of animal or vegetable origin, are derivatives of anthraquinone (See Table II). The principal red coloring matter of madder is alizarin, or 1,2-dihydroxyanthraquinone. Natural madder contains a considerable amount of another colorant, purpurin, or 1,2,4-trihydroxyanthraquinone, which accounts for the various shades of red to purplish-red that can be obtained when different sources of madder are used. In almost every source that describes dyeing with anthraquinone derivatives, the use of a metallic salt is mentioned. The principal metals used were aluminum, iron, tin, and in later years, chromium. The resulting color on the fiber depended in large part upon the metal used since the dyes chelated with the metal ions. The colors of different chelate compounds with alizarin and cochineal are shown in Table HI. 

Evidence to support this proposal has been obtained by Burnett and Thomson in work with the madder plant (Rubia tinctorum). 2-[ C]-Mevalonic acid was administered to this plant and was incorporated into a series of anthraquinone metabolites such as alizarin (101), purpurin (124) and pseudopurpurin (102). Degradation of the quinones to phthalic acid showed that all the radioactivity was confined to ring C. Decarboxylation of pseudopurpurin (102) gave purpurin (124) containing one half of the total radioactivity and this is in agreement with the hypothesis outlined above namely that ring C of these quinones is derived by cyclisation of a precursor such as lapachol (122). Burnett and Thomson s observations imply that the two methyl groups in the precursor (122)... 

Madder is characterised by the presence of a series of key anthraquinone components, the most important of which are alizarin, purpurin and pseudopurpurin, molindone, xanthop-urpurin, rubiadin (qq.v.), although a large group of other anthraquinones is also present. Schweppe and Winter list the following additional components found in the various madder species munjistin, ibericin, lucidin, 2-hydroxyan-thraquinone, xanthopurpurin-3-methyl ether, alizarin-1-methyl... 

Purpurin, 1,2,4-trihydroxyanthraquiiione, is an anthraquinone foimd in association with alizarin and pseudopnrpurin in dyestuffs derived from various Rubiaceae ( madder ) species therefore a common component of lake pigments produced from them. It is also produced synthetically and may be used for so-called aHzarin violet . The synthetic form is hsted in the Colour Index (1971) as Cl 58205, the natural form as Cl 75410. 

Anthraquinone group Naphthoquinones group Alizarin Alkanet Alkannin Aloe Aloe-emodin Aloin Carminic acid Carthamin Cochineal Juglone Kermes Kermesic acid Lac Laccaic acid Madder Munjistin Pseudopurpurin Purpurin Rubiadin Safflower Walnut... 

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