Preparation and Properties of Some Peri-Hydroxyquinone Inner Complexes<sup>1</sup>

Geyer, Bradford P.; Smith, G. McP.

doi:10.1021/ja01259a049

Cited by 8 publications

(2 citation statements)

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“…There is only one significant plant anthraquinone dye, alizarin [72-48-0] (CI Natural Red 6,8,9,10,11,and 12;CI 75330). In ancient times, alizarin was the preferred red dye.…”

Section: Alizarinmentioning

confidence: 99%

Dyes, Natural

Cofrancesco¹

2009

Kirk-Othmer Encyclopedia of Chemical Technology

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From the earliest times humans admired the beautiful natural colors of plants and minerals and sought to enhance human appearance by color. Ancient peoples used these dyes in cosmetics,food, and as medicine. The greatest use of natural dyes occurred when the art of weaving was developed. A few synthetic dyes were manufactured before 1856, but the big break through in synthetic dye manufacture came from Perkin who developed the synthesis for the dye Mauve. Synthetic dyes replaced natural dyes, but natural dyes are making a comeback. Hand dyeing is popular and there is an ever increasing demand for natural dyes as food colorings. This article discusses those natural dyes formerly manufactured. Basic categores include anthraquinones; napthoquinone dyes; indigoid dyes, and the natural food colors.The use of biogenic sources for color is a common practice, and for the most part, these do not produce adverse reactions. However, a few biogenic substances have been linked to allergic type reactions. Literature makes reference to carmine and annatto. Regulations of natural dyes are not numerous, but are discussed here.

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“…There is only one significant plant anthraquinone dye, alizarin [72-48-0] (CI Natural Red 6,8,9,10,11,and 12;CI 75330). In ancient times, alizarin was the preferred red dye.…”

Section: Alizarinmentioning

confidence: 99%

Dyes, Natural

Cofrancesco¹

2009

Kirk-Othmer Encyclopedia of Chemical Technology

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“…The isomer ratio was maintained through aromatization. For the purpose of assignment, we compared those chemical shifts with that of the known 1-hydroxyanthraquinone 15 and newly prepared 5hydroxy-1,4-dimethylanthraquinone. While the phenolic proton of the former resonated at δ 12.60, that of the latter appeared at δ 12.70.…”

Section: Diels-alder Reaction Of Juglone and Unsymmetrical Dienesmentioning

confidence: 99%

Importance of the role of secondary orbital interactions in the Diels–Alder reaction. Regioselectivity in the catalyzed and uncatalyzed reactions of juglone and aliphatic dienes

Motoyoshiya¹,

Kameda²,

Asari³

et al. 1997

J. Chem. Soc., Perkin Trans. 2

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The regioselectivities in the uncatalyzed and catalyzed Diels-Alder (DA) reactions of juglone with piperylene (penta-1,3-diene) or 2,3-dimethylpenta-1,3-diene have been investigated, employing Lewis acids such as boron trifluoride (BF 3 ) and sterically hindered aluminium catalysts in order to verify the role of the secondary orbital interactions (SOI). While the results of the uncatalyzed and catalyzed reactions using BF 3 or aluminium trimethoxide agree with the prediction made by the frontier molecular orbital (FMO) theory considering SOI, steric repulsion of the aluminium catalysts causes orderly changes to the ratios of the product regioisomers, which could be interpreted by diminution of SOI. The transition states are located by AM1 calculations and their energies are estimated by CDNO/2-CI and ab initio 6-31G* calculations. The regioselectivities observed in the experiments are explained by comparison of their energies. A zwitterionic mechanism in the catalyzed reaction was strongly supported and the molecular orbital feature suggests the contribution of SOI which would stabilize the transition state to control the reaction pathway.

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Dyes, Natural

Cofrancesco¹

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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With Perkin's syntheses of Mauve in 1856, the age‐old usage of natural dyes for textiles and foods greatly diminished. However, scientific interest in natural dyes continued. In 1868, the first laboratory synthesis of a natural dye, alizarin, was accomplished, followed by the manufacture of the dye. Later, indigotin was synthesized and ultimately manufactured. The structure of many other natural dyes was determined and verified by synthesis: anthraquinones, naphthoquinones, flavones, anthocyaniddins, and others. In the field of anthraquinones, some remarkable discoveries were reported: laccaic acid was shown to be a mixture of acids, and the wrong structure had been assigned to carminic and kermisic acid. The correct structure of the latter was established using the newly developed regiospecific method of synthesis. The structure of Tyrian Purple was determined and the dye synthesized. Much later, the precursors of the dye were isolated and identified. Since the early 1970s there has been a renewal of interest in natural dyes for use as food colorants. This was prompted mainly by FDA's deletion of certain synthetic dyes used for coloring foods. Some natural dyes are on FDA's list of approved dyes for coloring foods. However, their range of color is limited, so that other sources of natural dyes have been investigated. Among these was the red beet whose color is due primarily to a red dye and a small amount of a yellow dye. Both were isolated and synthesized and found to have unique chemical structures. By a suitable modification of the chlorophyll molecule, a useful food dye has been obtained.

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Preparation and Properties of Some Peri-Hydroxyquinone Inner Complexes¹

Cited by 8 publications

References 1 publication

Dyes, Natural

Dyes, Natural

Importance of the role of secondary orbital interactions in the Diels–Alder reaction. Regioselectivity in the catalyzed and uncatalyzed reactions of juglone and aliphatic dienes

Dyes, Natural

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Preparation and Properties of Some Peri-Hydroxyquinone Inner Complexes1

Cited by 8 publications

References 1 publication

Dyes, Natural

Dyes, Natural

Importance of the role of secondary orbital interactions in the Diels–Alder reaction. Regioselectivity in the catalyzed and uncatalyzed reactions of juglone and aliphatic dienes

Dyes, Natural

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Preparation and Properties of Some Peri-Hydroxyquinone Inner Complexes¹