Young Fustic(CHAPTER VII. Flavonol Group.)

The Natural Organic Colouring Matters
By
Arthur George Perkin, F.R.S., F.R.S.E., F.I.C., professor of colour chemistry and dyeing in the University of Leeds
and
Arthur Ernest Everest, D.Sc., Ph.D., F.I.C., of the Wilton Research Laboratories; Late head of the Department of Coal-tar Colour Chemistry; Technical College, Huddersfield
Longmans, Green and Co.
39 Paternoster Row, London
Fourth Avenue & 30th Street, New York
Bombay, Calcutta, and Madras
1918

Kaikki kuvat (kemialliset kaavat) puuttuvat // None of the illustrations (of chemical formulas) included.

Cotinus coggygria

Young fustic consists of the wood of the stem and larger branches of the Rhus cotinus (Linn.), a small tree which is a native of Southern Europe, and the West India Islands. It is a hard compact yellow wood, and is usually imported in small bundles or faggots. Within the last few years young fustic has almost disappeared from the market, not only on account of the artificial colouring matters, but because the shades it yields lack permanence, and the percentage of colouring matter it contains is small. The leaves of the R. cotinus constitute Venetian sumach, a tanning material which is employed to some extent in Italy and Southern Europe.

Fisetin, C₁₅H₁₀O₆, the colouring matter of young fustic, was first isolated by Chevreul ("Leçons de Chimie appliquee a la Teinture," A. ii., 150), who gave it the name "Fustin". Bolley (Schweiz. polyt. Zeitschr., 1864, 9, 22) considered that it was identical with quercetin, but Koch (Ber., 5, 285) maintained that fisetin was probably an aldehyde of quercetinic acid.

Schmid (Ber., 1886, 19, 1734), who carried out an exhaustive examination of this dyewood, obtained fisetin in a pure condition and proved that it was not identical with quercetin. He found that in addition to the free colouring matter, young fustic contains a glucoside of fisetin combined with tannic acid to which he gave the name of fustin tannide.

To prepare fisetin, Schmid (loc. cit.), and later Herzig (Monatsh., 12, 178), employed "cotinin" (v. infra), a commercial preparation of young fustic which is no longer on the market. According to Perkin and Pate (Chem. Soc. Trans., 1895, 67, 648), fisetin is readily isolated from the dyewood as follows:

Young fustic is extracted with boiling water, and the extract treated with lead acetate solution. The lead compound of the colouring matter is collected, made into a thin paste with water, and in a fine stream run into boiling dilute sulphuric acid. After removal of lead sulphate the dark-coloured filtrate, on cooling, deposits a semicrystalline brownish mass, which is collected and purified by crystallisation from dilute alcohol.

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Fisetin is a strong colouring matter and gives shades which are almost identical with those produced by quercetin, rhamnetin, and myricetin. The colours given with wool mordanted with chromium, aluminium, and tin are, respectively, red-brown, brown-orange, and bright red-orange (Perkin and Hummel, Chem. Soc. Trans., 1896, 69, 1290).

The glucoside of fisetin, according to Schmid (loc. cit.), is prepared as follows: A boiling aqueous extract of young fustic is treated with lead acetate, the precipitate removed, the clear liquid freed from lead by means of sulphuretted hydrogen, and saturated with salt. The mixture is filtered, the filtrate extracted with ethyl acetate, and the extract evaporated. There is thus obtained a residue consisting of the crude fustin-tannide, which is purified by solution in water, precipitation with salt, and extraction with ethyl acetate.

Fustin tannide crystallises in long yellowish- white needles, which are easily soluble in water, alcohol, and ether. When heated it decomposes above 200°. If a solution of fustin tannide in hot acetic acid is treated with water, and allowed to stand for some time, colourless crystals of fustin are gradually deposited.

Fustin crystallises from water in yellowish-white needles, melting-point 218-219°, and when digested with boiling dilute sulphuric acid gives fisetin and a sugar, the nature of which has not been determined. The formula given to this glucoside C₅₈H₄₆O₂₃ by Schmid cannot be regarded as correct, in view of the fact that the true formula of fisetin is now known to be C₁₅H₁₀O₆.

Dyeing Properties of Young Fustic.

The colours derived from young fustic are all fugitive to light, hence this dyestuff has lost its importance. In silk dyeing it was formerly used for dyeing brown, the silk being mordanted with alum, and afterwards dyed with a decoction of young fustic, peachwood, and logwood. With the various metallic salts as mordants young fustic yields colours somewhat similar to those obtained from old fustic, the chromium colour is, however, much redder, being a reddish-brown, and the aluminium yellow is much duller; stannous chloride on the contrary gives an incomparably more brilliant orange, not unlike that obtainable from flavin or from Persian berries (Hummel).

Fisetin is present also as glucoside in the wood of the yellow cedar, Rhodosphacra rhodanthema, and in the wood of the Quebracho Colorado (loc. cit.).

The leaves of the R. cotinus contain myricetin.

Robinia pseud-acacia, Flowers (CHAPTER VII. Flavonol Group.)

The Natural Organic Colouring Matters
By
Arthur George Perkin, F.R.S., F.R.S.E., F.I.C., professor of colour chemistry and dyeing in the University of Leeds
and
Arthur Ernest Everest, D.Sc., Ph.D., F.I.C., of the Wilton Research Laboratories; Late head of the Department of Coal-tar Colour Chemistry; Technical College, Huddersfield
Longmans, Green and Co.
39 Paternoster Row, London
Fourth Avenue & 30th Street, New York
Bombay, Calcutta, and Madras
1918

Kaikki kuvat (kemialliset kaavat) puuttuvat // None of the illustrations (of chemical formulas) included.

Robinin was first isolated from the flowers of the white Azalea by Zwengerand Dronke (Annalen, Supp., 1861, 1, 263), who considered that it was a glucoside of quercetin. Perkin (Chem. Soc. Trans., 1902, 81, 473) has shown that this is not the case.

To prepare the glucoside the flowers are exhausted with boiling alcohol, the solution concentrated by evaporation and poured into water. The mixture is extracted with ether, and the aqueous liquid distilled down to a small bulk. On standing, crystals of robinin separate, which are purified by crystallisation from water.

Robinin, according to Perkin, consists of pale yellow needles, sintering at 190 and melting at 196-197°, and when air-dried it possesses the formula C₂₃H₄₂O₂₀, 8H₂O.

Boiling dilute sulphuric acid hydrolyses robinin with formation of kaempferol, 2 molecules of rhamnose and 1 of glucose, according to the following equation:
C₂₃H₄₂O₂₀ + 4H₂O = C₁₅H₁₀O₆ + 2C₆H₁₄O₆ + C₆H₁₂O₆

Schmidt (Chem. Zentr., 1901, ii., 121), who examined robinin at almost the same time, also obtained by its hydrolysis a colouring matter C₁₅H₁₀O₆, the acetyl compound of which melts at 182-183° (evidently kaempferol), and Waljascko (J. Russ. Phys. Chem. Soc., 1904, 36, 421), again, no doubt, also unaware of the communication of Perkin, terms this colouring matter C₁₅H₁₆O₆, H₂O, robigenin. Robinin he considered to possess the formula C₃₃H₄₀O₁₉.7½H₂O, and the sugars that it yields by hydrolysis to consist of galactose (1 mol.) and rhamnose (2 mols.).

Robinin is a most interesting glucoside, and with the exception of xanthorhamnin is the only known substance of this class which yields three sugar nuclei. It is practically devoid of tinctorial property.

Interesting is the fact that whereas the bark of this plant contains acacetin, the monomethyl ether of the trihydroxyflavone, apigenin, its flowers yield the glucoside of the trihydroxyflavonol kaempferol. Whether the occurrence of distinct flavones in various portions of the same plant is exceptional or otherwise, has been little studied, and appears to have only been observed elsewhere in the cases of the yellow cedar (Rhodesphaera rhodanthema), the leaves of which contain quercetin and the stem fisetin, and the Venetian sumach, the stem of which contains fisetin and the leaves myricetin.

Delphinium consolida, Flowers (Kaempferol)(CHAPTER VII. Flavonol Group.)(Osa artikkelista)

The Natural Organic Colouring Matters
By
Arthur George Perkin, F.R.S., F.R.S.E., F.I.C., professor of colour chemistry and dyeing in the University of Leeds
and
Arthur Ernest Everest, D.Sc., Ph.D., F.I.C., of the Wilton Research Laboratories; Late head of the Department of Coal-tar Colour Chemistry; Technical College, Huddersfield
Longmans, Green and Co.
39 Paternoster Row, London
Fourth Avenue & 30th Street, New York
Bombay, Calcutta, and Madras
1918

Kaikki kuvat (kemialliset kaavat) puuttuvat // None of the illustrations (of chemical formulas) included.

Delphinium consolida is a common European plant belonging to the Larkspur family; its name refers to its powers, real or imaginary, of healing or consolidating wounds. The blue flowers were examined by Perkin and Wilkinson (Chem. Soc. Trans., 1902, 81, 585) to determine if these yield the same colouring matters as those previously isolated from the flowers of the D. zalil (ibid., 1898, 73, 267). The presence of kaempferol only could, however, be detected. For its isolation an aqueous extract of the flowers was digested at the boiling-point with addition of sulphuric acid, and the brown resinous product which separated on keeping, extracted with alcohol and the extract evaporated to a small bulk. Addition of ether to this solution caused the precipitation of resinous impurity, and on evaporating the ethereal liquid a semi-crystalline residue of the crude colouring matter was obtained. The product was crystallised from dilute alcohol, converted into acetyl derivative, and this after purification retransformed into colouring matter in the usual manner. The yield was approximately 1 per cent.

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Kaempferol possesses well-defined dyeing properties, and gives with mordanted woollen cloth the following shades which closely resemble those given by morin (loc. cit.):
Chromium. Brownish-yellow.
Aluminium. Yellow.
Tin. Lemon-yellow.
Iron. Deep olive-brown.

It is also present in the Impatiens balsamina (Chantili Pass), the Erythrina stricta (vernacular name "Kon kathet"), (Perkin and Shulman, Chem. Soc. Proc., 1914, 30, 177), the berries of the Rhamnus catharticus (loc. cit.), and together with quercetin, both apparently as glucosides, in the flowers of the Prunus spinosa (Perkin and Phipps, Chem. Soc. Trans., 1904, 85, 56). For the separation of the two colouring matters a fractional crystallisation from acetic acid was employed, kaempferol in these circumstances being the more sparingly soluble.