Osage Orange(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.

Though the wood of this tree has been used for many years in a desultory manner for dyeing by the Indians in the Red Valley region of Texas, America, its employment as a dyestuff has only recently engaged the attention of the United States Forest Service. As the -result of its examination by Kressmann (Journ. Amer. Leather Chemists Association, 1915, 347), it has been found that its dyeing properties are very similar to those given by old fustic, the shades which it produces being, however, slightly purer and somewhat less red in tint. A qualitative study of the aqueous extract showed that the dyeing principles present consisted as in old fustic of morin and maclurin, but that the unknown red constituent present in this latter was practically absent. Though apparently the tinctorial strength of distinct samples of the osage orange wood is somewhat variable, this is probably on the average quite equal to that of old fustic, and this wood can be satisfactorily employed not only for textile but also for leather dyeing.

Old Fustic(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.

Old fustic is the wood of a tree known as the Chlorophora tinctoria (Gaudich), previously called Morus tinctoria (Linn.), which occurs wild in different tropical regions. The tree frequently grows to a height of over 60 feet, is exported in the form of logs, sawn straight at both ends, and usually deprived of the bark. The best qualities of old fustic come from Cuba and the poorer from Jamaica and Brazil. It is at the present time used very largely, and, together with logwood, is the most important of the natural dyestuffs.

The colouring matters of old fustic were first investigated by Chevreul ("Leçons de chimie appliquee à la teinture," ii., 150), who described two substances, one sparingly soluble in water, called morin, and a second somewhat more readily soluble. Wagner (J. pr. Chem., (i.), 51, 82) termed the latter moritannic acid, and considered that it possessed the same percentage composition as morin. Hlasiwetz and Pfaundler (Annalen, 127, 351), on the other hand, found that the so-called moritannic acid was not an acid, and as moreover its properties were quite distinct from those of morin, they gave it the name "Maclurin ".

Morin, C₁₅H₁₀O₇, 2H₂O. To isolate this colouring matter from old fustic a boiling extract of the rasped wood is treated with a little acetic acid and then with lead acetate solution. This causes the precipitation of the morin in the form of its yellow lead compound, whereas the main bulk of the maclurin remains in solution. The washed precipitate in the form of a thin cream is run into boiling dilute sulphuric acid, and the hot liquid, after decantation from the lead sulphate, is allowed to stand. Crystals of crude morin are gradually deposited, and a further quantity can be isolated from the acid solution by means of ether. During the preparation of commercial fustic extract, the solution on standing, or the concentrated extract itself, deposits, as a rule, a brownish-yellow powder, which consists principally of a mixture of morin and its calcium salt, and this forms the best source for the preparation of large quantities of the colouring matter. The product is digested with a little boiling dilute hydrochloric acid to decompose the calcium compound, extracted with hot alcohol, and the extract evaporated. Crystals of morin separate on standing, and a further quantity can be isolated by the cautious addition of a little boiling water to the mixture.

Crude morin can be partially purified by crystallisation from dilute alcohol or dilute acetic acid, but the product usually contains a trace of maclurin. To remove the latter the finely powdered substance is treated in the presence of a little boiling acetic acid with fuming hydrobromic acid (or hydrochloric acid), which precipitates the morin as halogen salt, whereas the maclurin remains in solution (Bablich and Perkin, Chem. Soc. Trans., 1896, 69, 792). The crystals are collected, washed with acetic acid, decomposed by water, and the regenerated morin crystallised from dilute alcohol.

Morin crystallises in colourless needles (Bablich and Perkin), readily soluble in boiling alcohol, soluble in alkaline solutions with a yellow colour. Lead acetate solution gives a bright orange-coloured precipitate and ferric chloride an olive-green coloration.

[---]

Morin dyes mordanted woollen cloth shades which, though of a slightly stronger character, closely resemble those given by kaempferol.
Morin
Chromium. - Olive-yellow.
Aluminium. - Yellow.
Tin. - Lemon yellow.
Iron. - Deep olive-brown.
Kaempferol
Chromium. - Brown-yellow.
Aluminium. - Yellow.
Tin. - Bright yellow.
Iron. - Deep olive-brown.
(Perkin and Wilkinson, Chem. Soc. Trans., 1902, 81, 590).

Maclurin, C₁₃H₁₀O₆. When morin is precipitated from a hot aqueous extract of old fustic by means of lead acetate the solution contains maclurin. After removal of lead in the usual manner, the liquid is partially evaporated and extracted with ethyl acetate, which dissolves the colouring matter. The crude product is crystallised from dilute acetic acid (Perkin and Cope).

A description of maclurin and its derivatives will be found in the chapter devoted to benzophenone compounds.

Dyeing Properties of Old Fustic.

In silk and cotton dyeing fustic is employed to a comparatively limited extent, but in wool dyeing it is the most important natural yellow dyestuff. The olive-yellow or old-gold colours which fustic yields when used with chromium mordant and the greenish-olives obtained with the use of copper and iron mordants are all fast to light and milling, but the yellow colours yielded in conjunction with aluminium and tin possess only a moderate degree of fastness with respect to light. Fustic is chiefly employed in wool dyeing with potassium dichromate as the mordant, and it is for the most part used along with other dyestuffs, e.g. logwood, alizarin, etc., for the production of various compound colours, olive, brown, drab, etc.

Yellow Wallflower - Cheiranthus cheiri (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.

The purplish-brown petals of the common garden wallflower are comparatively rich in colouring matter, though the shade given by these on alumina mordant possesses a greenish-olive-yellow tint, and is of a less pure character than that given by the variety known as "Cloth of Gold". A boiling aqueous extract of these latter flowers on treatment with sulphuric acid gradually deposits a yellow precipitate, and this is most readily purified by pouring the concentrated alcoholic solution into much ether. The main impurity is thus precipitated, whereas the colouring matter remains dissolved in the ether. By fractional crystallisation from alcohol two colouring matters can be isolated from this product, (a) sparingly soluble which consists of isorhamnetin (quercetin monomethyl ether) and (b) quercetin. The existence of isorhamnetin was first demonstrated by an examination of these flowers (Perkin and Hummel, Chem. Soc. Trans., 1896, 69, 1566).

Asbarg(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.

Asbarg consists of the dried flowers and flowering stems of the Delphinium zalil, which is found in great quantity in Afghanistan. The dyestuff is collected and taken to Multan and other Punjab towns, from which it is conveyed all over India. It is much used in silk dyeing for the production of a sulphur-yellow colour known as "gandkaki," and, together with Datisca cannabina, to obtain a similar shade on alum-mordanted silk; it is also used in calico-printing. The flowers, which are bitter, are likewise employed medicinally as a febrifuge.

The colouring matters of asbarg are present entirely as glucosides, and are best isolated in the crude condition by digesting the boiling aqueous extract with a little sulphuric acid (Perkin and Pilgrim, Chem. Soc. Trans., 1898, 268). A brownish-yellow powder thus separates, which contains three substances: isorhamnetin, quercetin, and kaempferol.

Isorhamnetin, C₁₆H₁₂O₇, the sparingly soluble constituent, forms yellow needles, resembling rhamnetin in appearance. With lead acetate in alcoholic solution, an orange-red precipitate is formed, whilst ferric chloride gives a greenish-black coloration. Fused with alkali, phloroglucinol and protocatechuic acid are produced, and when air is aspirated through its alkaline solution, phloroglucinol and vanillic acid are obtained.

With acetic anhydride isorhamnetin gives a tetra-acetyl derivative, C₁₆H₈O₇(C₂H₃O)₄, colourless needles, melting-point 195-196°; and with methyl iodide a trimethyl ether, which is identical with quercetin tetramethyl ether. As, moreover, by the action of hydriodic acid wrhamnetin yields quercetin, its constitution can only be represented as follows: [KUVA PUUTTUU]

The dyeing properties of isorhamnetin are similar in character to those given by kaempferol. isoRhamnetin is also present in yellow wallflowers (Cheiranthus cheiri) (Perkin and Hummel), and in red clover flowers, Trifolium pratense (Power and Salway, Chem. Soc. Trans., 1910, 97, 245). A description of the more soluble colouring matters quercetin (quercitron bark) and kaempferol (Delphinium consolida) is given elsewhere.

In dyeing properties asbarg closely resembles quercitron bark, but yields with aluminium mordant a purer or less orange-yellow. It is, however, a much weaker dyestuff, having but 35 per cent, the dyeing power of quercitron bark. The colouring matter of the flowers, apart from the flowering stalks, is present to the extent of 3,47 per cent.

The stems and flowers of the D. saniculafolium give shades analogous to, though somewhat weaker than, those yielded by the D. zalil.

Rhamnus catharticus(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.

The Rhamnus catharticus or Purging Buckthorn, indigenous to Great Britain, is a stiff many-branched shrub growing from five to ten feet high, the fruit of which consists of small berries, resembling when dry black pepper-corns. Formerly it was in great demand as a medicine, but has now fallen into disrepute. The juice of the berries admixed with lime and evaporated to dryness constitutes the pigment known as "sap" or "bladder green". According to Tschirch and Polacco (Arch. Pharm., 1900, 238, 459) the yellow tinctorial constituents yielded by the berries of this plant are quite distinct from those given by the berries of the various species of Rhamnus which constitute the Persian berry proper. Thus in addition to rhamno-emodine they isolated four yellow crystalline substances, rhamnocitrin, β-rhamnocitrin, rhamnochrysin, and rhamnolutin. Rhamnocitrin was considered to consist of the trihydroxy derivative of a dihydroxanthone [KUVA PUUTTUU] rhamnolutin of a tetrahydroxyflavone isomeric with luteolin and fisetin, and rhamnochrysin an oxidation product of rhamnocitrin, whereas β-rhamnocitrin was distinct from rhamnetin and indeed contains no methoxy groups.

Valiaschko and Krasowski (J. Russ. Phys. Chem. Soc., 1908, 40, 1502) and Krasowski (ibid., 1510) criticised this paper of Tschirch and Polacco, and could not isolate the compounds described by these latter authors. On the other hand, quercetin, rhamnetin, and xanthorhamnin, the glucoside of rhamnetin, were found to exist in these berries, and it seemed likely that the rhamnolutin of Tschirch and Polacco was rhamnetin and their rhamnochrysin a mixture of quercetin and emodine.

Oesch and Perkin (Chem. Soc. Trans., 1914, 105, 2350) also isolated rhamnetin from these berries, together with a small amount of quercetin, and considered that the former represents the β-rhamnocitrin of Tschirch and Polacco. The main colouring matter present, however, is kaempferol, C₁₅H₁₀O₆, the trihydroxyflavonol which can be obtained from the flowers of the Delphinium salil and D. consolida, and this is to be regarded as the so-called "rhamnolutin".

A fourth compound, evidently the rhamnocitrin of these latter authors, possessed the formula C₁₆H₁₂O₆, rather than C₁₅H₁₀O₅ which they assigned to it. This crystallised in yellow leaflets, melting-point 221-222°, and its acetyl derivative at 200-201°, and these melting-points are practically the same as those given by Tschirch and Polacco. It contains one methoxy group, by the action of hydriodic acid yields kaempferol, and is evidently a kaempferol monomethyl ether. It bears considerable resemblance to kaempferide, a monomethyl ether of kaempferol present in Galanga root, Alpinia officinarum (Jahresber., 1881, 14, 2385), which, however, melts at 227-229°, and its acetyl derivative at 193-195°, and though there is thus strong probability that the two compounds are not identical, Oesch and Perkin suggest that further work on this point is desirable.

Persian Berries(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.

Persian berries are the seed-bearing fruit of various species of Rhamnus, growing wild or cultivated in France, Spain, Italy, the Levant, and Persia. The Persian berry proper is obtained from R. amygdalinus, R. oleoides, and R. saxatilis, and is imported from Smyrna and Aleppo. Its size is about that of a pea, colour yellowishgreen, surface much shrivelled, hard, and divisible along well-marked depressions forming a cross, into four parts, each containing a triangular seed; its taste is intensely bitter.

Avignon or French berries, the product of R. infectorius (Linn.) and R. alaternus (Linn.), are smaller in size than the foregoing and contain only two seeds.

Spanish, Italian, and Hungarian berries are respectively the products of R. saxatilis, R. infectorius (Linn.), and R. cathartica (Linn.). These are similar in quality to the Avignon berries. Other qualities come from the Morea, Wallachia, and Bessarabia.

All of these botanical varieties do not contain entirely the same constituents, but, on the other hand, there is every reason to suppose that the colouring constituents of those to which the term Persian berry proper is applied are identical in each case.

Gelatly (Edinburgh New Phil. Jour., 7, 252) was the first to isolate from Persian berries (R. tinctoria, Wald. et Kit.) the glucoside xanthorhamnin, C₄₅H₅₆O₂₈, which on hydrolysis with acid gave a sugar and a colouring matter rhamnetin. Hlasiwetz (Annalen, 112, 107) considered that xanthorhamnin was identical with quercitrin, and rhamnetin with quercetin, but Schützenberger and Berteche (Bull. Soc. Ind. Mulhouse, 35, 456) denied this, and assigned to rhamnetin the formula C₁₂H₁₀O₅. Xanthorhamnin, which Schützenberger (Jahres., 1868, 774) termed α-rhamnegin was considered to possess the formula C₂₄H₃₂O₁₄. The presence of a second glucoside, β-rhamnegin, was also detected by this chemist, and from this by hydrolysis fi-rhamnetin was derived. Liebermann and Hörmann (Annalen, 196, 313) also investigated Persian berries, devised a method for the preparation of xanthorhamnin and rhamnetin, and prepared various derivatives of the latter.

It is now known that Persian berries contain the glucosides of three colouring matters, namely rhamnetin, rhamnazin, and quercetin (Herzig, Monatsh., 6, 889; 9, 549; 12, 175; Perkin and Geldard, Chem. Soc. Trans., 1895, 67, 500).

To isolate these substances Persian berries are extracted with boiling water, the solution treated with a small quantity of sulphuric acid, and digested while boiling for one hour. The glucosides are thus hydrolysed and the crude colouring matters separate in the form of a greenish-yellow precipitate.

The product is extracted with boiling alcohol, which dissolves principally the quercetin, this being the most soluble of the three colouring matters. The residue now contains rhamnetin and rhamnazin, and the latter is removed from the former by two or three extractions with boiling acetic acid.

Rhamnetin, C₁₆H₁₂O₇, crystallises in yellow needles very sparingly soluble in acetic acid and alcohol. It dissolves in alkaline solutions with a pale yellow colour, and gives with alcoholic lead acetate an orange-red precipitate. When acetylated it forms tetra-acetylrhamnetin, C₁₆H₈O₇(C₂H₃O)₄ (Liebermann and Hörmann), colourless needles, melting-point 183-185°, and on bromination dibromrhamnetin is produced.

Rhamnetin sulphate, C₁₆H₁₂O₇.H₂SO₄ (Perkin and Pate, Chem. Soc. Trans., 1895, 67, 650), orange-red needles, and monopotassium rhamnetin, C₁₆H₁₁O₇K (Perkin and Wilson, ibid., 1903, 83, 136), orange-yellow needles, have been prepared.

Rhamnetin is in reality a quercetinmonomethyl ether (Herzig, loc. cit.}, for on digestion with hydriodic acid it is converted into quercetin, and when methylated with methyl iodide quercetintetramethyl ether is produced.

By the action of boiling potassium hydroxide solution, of boiling alcoholic potash, or by aspirating air through its alkaline solution, rhamnetin gives protocatechuic acid, and a syrupy phloroglucinol derivative. The latter, identified by means of its diazobenzene compound, consists of phloroglucinol monomethyl ether (Perkin and Allison, Chem. Soc. Trans., 1902, 81, 470), and consequently the constitution of rhamnetin is to be expressed as follows [KUVA PUUTTUU]

Rhamnetin is a strong dyestuff, and gives on mordanted woollen cloth shades which are practically identical with those produced by quercetin:
Chromium - Red-brown.
Aluminium - Brown-orange.
Tin - Bright Orange.
Iron - Deep olive.
(Perkin and Wilkinson, ibid., 1902, 81, 590).

Rhamnazin, C₁₇H₁₄O₇ (P. and G.), yellow needles, melting-point 214-215°, is moderately soluble in boiling toluene, a property which distinguishes it from both rhamnetin and quercetin. It dissolves in alkaline liquids to form orange-yellow solutions, and with alcoholic ferric chloride gives an olive-green coloration.

Acetylrhamnazin, C₁₇H₁₁O₇(C₂H₃O)₃, colourless needles, benzoylrhamnazin, C₁₇H₁₁O₇(C₇H₆O)₃, colourless needles, melting-point 204-205°, and dibromrhamnazin, C₁₇H₁₂Br₂O₇, yellow needles, have been prepared.

Rhamnazin is a quercetin dimethyl ether. Digested with boiling hydriodic acid, it is converted into quercetin, and by methylation in the ordinary manner gives quercetin tetramethyl ether. Boiling alcoholic potash hydrolyses rhamnazin with formation of vanillic acid and phloroglucinol monomethyl ether (Perkin and Allison, loc. cit.). It accordingly possesses the constitution [KUVA PUUTTUU]

Rhamnazin does not readily dye mordanted calico, but on mordanted wool gives shades resembling those which are produced by kaempferol-
Chromium - Golden-yellow
Aluminium - Orange-yellow
Tin. - Lemon-Yellow.
Iron - Olive-brown.
Only a small amount of this colouring matter is present in Persian berries.

Xanthorhamnin, C₂₃H₄₂O₂₀, is readily prepared by extracting powdered Persian berries with three times their weight of boiling 85 per cent, alcohol. On standing the dark brown filtered extract deposits a large quantity of the impure glucoside as a brown resinous mass. From the supernatant liquid on standing a purer xanthorhamnin separates in the form of a pale yellow cauliflower-like precipitate, and in such quantity as to congeal the whole liquid to a stiff paste. This is collected, repeatedly crystallised from alcohol, and finally from alcohol containing a little water and ether (Liebermann and Hörmann, loc. cit.}.

Xanthorhamnin consists of pale yellow needles readily soluble in water and hot alcohol, soluble in alkaline solutions with a yellow colour. With basic lead acetate it gives an orange precipitate. According to the work of Liebermann and Hörmann, xanthorhamnin, when hydrolysed with acid, gives rhamnetin and rhamnose, C₈H₆₆O₂₉ + 5H₂O = 4C₆H₁₄O₆ + 2C₁₂H₁₀O₅

More recently, however, Xanthorhamnin has been shown to possess the formula C₃₄H₄₂O₂₀, and that by means of its specific ferment rhamninase, contained by Persian berries, it is hydrolysed with formation of rhamnetin and a complex sugar rhamninose, C₁₈H₃₂O₁₄, C₂₄H₄₂O₂₆+H₂O=C₁₆H₁₂O₇+C₁₈H₃₂O₁₄

When rhamninose is digested with boiling dilute acids, it is converted into 2 molecules of rhamnose, and 1 molecule of galactose (C. and G. Tanret, Comptes rend., 1899, 129, 725), C₁₈H₂₂O₁₄+4H₂O=C₆H₁₂O₆+2C₆H₁₄O₆

No glucosides of rhamnazin or quercetin have been isolated as yet from Persian berries.

The action of the ferment rhamninase is readily demonstrated. If crushed Persian berries, contained in a muslin bag, are suspended in water heated to 40°, a yellow solution containing the glucosides is produced; this quickly becomes opaque and a heavy precipitate of the mixed colouring matters eventually separates. To within recent years this reaction was carried out on a commercial scale, and the product was placed on the market under the name of "rhamnétine". This reaction can be employed to distinguish between the dyeing properties of the glucosides contained in the berries, and the free colouring matters produced by their hydrolysis. Thus if Persian berries be added to a cold dye-bath, and this is slowly heated to boiling, the glucosides are hydrolysed by the ferment; but if, on the other hand, the berries be at once plunged into boiling water, the ferment is killed and a solution of the glucosides is obtained. In the former case wool mordanted with tin gives an orangered shade, whereas in the latter a pure yellow colour is produced.

Beyond the ordinary extract of Persian berries which is prepared in large quantity by extracting the berries with boiling water, and evaporating the solution under reduced pressure, no special commercial preparations are manufactured at the present time.

Dyeing Properties.

In wool dyeing Persian berries are little employed on account of their cost; moreover, they possess no special advantage over quercitron bark and old fustic. Persian berries, as a rule, give redder shades than quercitron bark, a fact which is to be explained as due to the hydrolysis of its glucosides by the ferment. The quercitrin of quercitron bark is not accompanied by such a specific ferment, and consequently the shades given by this dyestuff are of a yellower character. With tin mordant Persian berries give bright yellows and oranges, which are only fairly fast to light; but according to Hummel, the yellowish-olive produced with copper mordant is extremely fast, and is darkened rather than otherwise by exposure. Persian berries are still used to a considerable extent in calico-printing for the formation of yellow, orange, and green shades.

Prunus emarginata (?)(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.

The bark of a spurious substitute for that of the Prunus serotina, probably P. emarginata, has been shown by Finnemore (Pharm. Journ., 1910, (iv.), 31, 604) to contain in addition to quercimeritrin (Perkin, Chem. Soc. Trans., 1909, 95, 243) a glucoside prunitrin, C₂₂H₂₄O₁₁, 4H₂O, fine needles, which when hydrolysed yields prunetin and glucose.

Prunetin, C₁₅H₉O₄.OCH₃, colourless needles, melting-point 242°, dissolves in alkalis with a slight yellow colour, and is sparingly soluble in all the usual solvents. Monacetylprunetin, C₁₆H₁₁O₅(C₂H₃O), pale yellow needles, melting-point 190°; diacetylprunetin, C₁₆H₁₀O₅(C₂H₃O)₂, melting-point 224-226°; benzoylprunetin, C₁₆H₁₀O₅(C₇H₅O)₂, needles, melting-point 215°; dimethylprunetin, C₁₅H₈O₃(OCH₃)₂, needles, melting- point 145°; and acetyldimethylprunetin, C₁₅H₇O₃(OCH₃)₂C₂H₃O, have been prepared.

Fused with caustic potash at 250°, prunetin gives phloroglucinol and p-hydroxyphenylacetic acid.

Prunetol, C₁₅H₁₀O₅, colourless needles, melting-point 290°, is formed by the demethylation of prunetin with hydriodic acid, and yields acetylprunetol, Cl5H7O5(C₂HO)₃, prunetol sulphate, C₁₅H₁₀O₅.H₂SO₄, yellow needles. On methylation with methyl iodide prunetol dimethyl ether, identical with prunetin monomethyl ether, and a sparingly soluble methyl ether, the acetyl derivative of which melts at about 186°, are produced (Finnemore, Chem. Soc. Trans., 1910, 98, 1102).

It is considered by this author that prunetin is closely related to scutellarein (Molisch and Goldschmiedt, loc. cit.) and may have the constitution [KUVA PUUTTUU]

Clover 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.

It has long been known that clover flowers dye a yellow colour on aluminium mordanted fabrics, and in the past they have been employed to a minor extent for dyeing purposes. Three varieties have been chemically examined, viz. those derived from the Trifolium pratense, the T. incarnatum, and the T. repens.

Trifolium pratense

The flowers known as the "common red clover," according to Power and Salway (Chem. Soc. Trans., 1910, 97, 231), contain in addition to isorhamnetin (quercetin monomethyl ether) and a glucoside of quercetin, melting-point 235°, numerous other phenolic substances, which, judging by their chemical properties, appear to be closely allied to the colouring matters of the flavone group. These are described below.

Pratol, C₁₅H₈O₂(OH).OCH₃, colourless needles, melting-point 253°, readily soluble in hot aqueous sodium carbonate and sodium hydroxide with a pale yellow coloration, yields the acetyl compound, C₁₅H₈O₂(OC₂H₃O).OCH₃, and is probably a hydroxymethoxyflavone.

A new yellow compound, C₁₈H₁₀O₇, thin yellow plates, melting point about 280°, is soluble in alkalis with a yellow colour, and its solution in sulphuric acid exhibits a brilliant green fluorescence. It contains a methoxy group and gives an acetyl compound, C₁₆H₆O₇(C₂H₃₀)_4l melting-point 145-147°.

Pratensol, C₁₇H₉O₂(OH)₃, is very readily soluble in alcohol, dissolves in alkali carbonates yielding yellow solutions, and its alcoholic solution gives with ferric chloride a greenish-black coloration. Triacetylpratensol, C₁₇H₉O₅(C₂H₃O)₃, colourless slender needles, melts at 189°.

A new phenolic substance, C₁₅H₇O₃(OH)₃, colourless needles, melting-point 225°, is soluble in alkali hydroxides, and gives with alcoholic ferric chloride a dark green coloration. The acetyl derivative, silky needles, has melting-point 209°.

The glucoside trifolin, C₂₂H₂₂O₁₁, H₂O, pale yellow needles, melts and decomposes at about 260°. It is soluble in alkalis with an intense yellow coloration, and dissolves in sulphuric acid, forming a yellow solution, which rapidly develops a brilliant green fluorescence. When hydrolysed it yields rhamnose and trifolitin, C₁₆H₁₀O₆, melting-point about 275°, readily soluble in alcohol,
C₂₂H₂₂O₁₁ = C₁₆H₁₀O₆ + C₆H₁₂O₅

* Both in its melting-point and that of its acetyl derivative there is a marked resemblance between trifolitin and kaempferol.Alkalis dissolve trifolitin with an intense yellow colour, alcoholic ferric chloride gives a dark green coloration, and alcoholic lead acetate an orange-yellow lead salt. It contains no methoxy group, and is unaltered when heated for several hours with 30 per cent, aqueous potassium hydroxide. It does not appear to belong to the flavone group, and differs from the flavone compounds by the fact that it does not give an oxonium salt with sulphuric acid, and only with difficulty a potassium compound by means of alcoholic potassium acetate. It may possibly consist of a tetrahydroxyphenylnaphthoquinone. The acetyl compound when rapidly heated melted at 116°, re-solidified at a higher temperature, and finally melted at 182°.*

The glucoside isotrifolin, C₂₂H₂₂O₁₁, isomeric with trifolin, consists of pale yellow needles, melting-point about 250°, and when hydrolysed yields similarly to the latter trifolitin, C₁₆H₁₀O₆, melting-point 275°. Though in general behaviour it is very similar to trifolin, it is much more soluble in alcohol, and does not appear to be identical with this glucoside.

In addition to these compounds the flowers contain salicylic acid, coumaric acid, myricyl alcohol, C₃₁H₆₃OH, heptacosane, C₂₇H₅₆, hentriacontane, C₃₁H₆₄, sitosterol, C₂₇H₄₆O, trifolianol, C₂₁H₃₄O₂(OH)₂, palmitic, stcaric, linolic, oleic, linolenic, and isolinotenic acids.

Trifolium incarnatum.

A considerable difference is exhibited between the constituents of the "carnation or crimson clover flowers" and those of the T. pratense or "common red clover".

According to Rogerson (Chem. Soc. Trans., 1910, 97, 1006) these flowers contain pratol, C₁₅H₈O₂(OH)(OCH₃), free quercetin, and a glucoside of quercetin, C₂₁H₂₀O₁₂, 3H₂O, to which the name incarnatrin is applied. This latter crystallises in yellow prismatic needles, melting-point 242-245°, dissolves in sulphuric acid with formation of a green fluorescent solution, and when hydrolysed yields quercetin and glucose according to the equation
C₂₁H₂₀O₁₂+H₂O=C₁₅H₁₀O₇+C₅H₁₂O₆

Incarnatrin is not identical with the quercimeritrin of Perkin (Chem. Soc. Trans., 1909, 95, 2181).

In addition to these substances the flowers yield furfuraldehyde, benzoic and salicylic acids, a trace of p-coumaric acid, incarnatyl alcohol, C₃₄H₆₉OH, hentriacontane, C₃₁H₆₄, a phytosterol, C₂₇H₄₆O, and palmitic, stearic, oleic, linolenic, and isolinolenic acids.

Trifolium repens.

The flowers of the white clover, T. repens, according to Perkin and Phipps (Chem. Soc. Trans., 1904, 85, 58), owe their tinctorial property to quercetin which is present as glucoside.

Podophyllum emodi(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.

P. emodi is a small herbaceous plant growing abundantly in Northern India. The root, or rather the rhizome, is employed medicinally in India as a powerful purgative, just, indeed, as the allied P. peltatum is used in Europe and America.

An examination of this root by Dunstan and Henry (Chem. Soc. Trans., 1898, 73, 209) has shown that in addition to podophyllotoxin, the active constituent, a considerable quantity of quercetin is present. According to Hummel this material in dyeing property compares favourably with quercitron bark, and should prove commercially valuable as a dyestuff at least to the native dyer.

Eucalyptus macrorhyncha(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.

Eucalyptus macrorhyncha (F. v. M.), a fair-sized tree, is the "red stringy bark" of New South Wales, and the ordinary stringy bark tree of Victoria (Smith, Chem. Soc. Trans., 1898, 73, 697).

The leaves yield under favourable conditions a very large amount (10 per cent.) of a crystalline glucoside termed by Smith myrticolorin, which can be isolated in the crude condition by mere extraction with boiling water. The solution on cooling became semi-solid owing to the separation of crystals, and these can be purified by extraction with ether to remove chlorophyll and crystallisation first from alcohol and subsequently from water. It formed pale yellow needles, gave on hydrolysis quercetin and glucose, and at first appeared to be a new glucoside of quercetin. Though very similar to rutin its identity with this glucoside was unsuspected in that rutin by hydrolysis was presumed at that time to give quercetin and 2 molecules of rhamnose (Schunck, ibid., 1888, 53, 264). Schmidt in 1908 (Arch. Pharm., 246, 214), however, pointed out that rutin in this manner yields not only rhamnose but glucose, and the probability that myrticolorin as also viola quercitrin and osyritrin (loc. cit.} were identical with rutin was subsequently confirmed by Perkin (ibid., 1910, 97, 1776).

Thespasia macrophylla(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.

Thespasia macrophylla, Blume (T. lampas, Dabz.). This is a small bush common to the tropical jungles of India, Burma, and Ceylon. In Watt's "Dictionary of the Economic Products of India" there is no mention of the use of this plant as a dyestuff, but, on the other hand, the capsules and flowers of the allied T. populnea (Soland) are stated to give a yellow dye.

According to Perkin (Chem. Soc. Trans., 1909, 95, 1859) tne flowers of the T. macrophylla yield quercetin and some quantity of protocatechuic acid.

With mordanted woollen cloth the flowers produce fairly good shades, but are in no way superior to the better-known Indian natural yellow dyestuffs.

Heather or Calluna vulgaris(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.

In former times the common heath or heather, until recently named Erica vulgaris, was used as a dyestuff for producing a yellow colour on - woollen goods (Crookes, "Dyeing and Calico Printing," 1874, p. 511). Although now almost superseded it was until recently employed in the home industries of outlying districts, such as the Highlands of Scotland. Bancroft ("Philosophy of Permanent Colours," 1813, 2, 1 08) states that all five species of the erica or heather found in Great Britain are, he believes, capable of giving yellows much like those obtained from dyer's brown. According, however, to the experiments of the late J. J. Hummel the E. tetralix (bell heather) and E. cinerea contain only traces of yellow colouring matter. Leuchs (Farben u. Färbekunde, 2, 320) refers to the tanning property of heather, and notes that the effect resembles in character that given by oak bark. H. R. Procter found it to contain 6.4 per cent, of tannin. The colouring matter was isolated by Perkin and Newbury (Chem. Soc. Trans., 1899, 75, 837) from an aqueous extract of the green portion of the plant, in which it appears only to reside, by precipitation with lead acetate in the usual manner. It proved to be identical with the quercetin of quercitron bark. The dyeing properties of heather, though distinctly weaker, are so similar in character to those given by quercitron bark as to require no special description. Experiment showed that 36 parts of the heather were necessary to obtain as good a result as that given by 10 parts of quercitron bark.

Onion Skins(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.

The outer dry skins of the bulb of the onion, Allium cepa (Linn.), were formerly employed for dyeing purposes. According to Leuchs (Farben und Färbekunde, 1825, 1, 434), "the outer skins of onion bulbs which are of a brownish-orange colour have long been used in Germany for dyeing Easter eggs yellow, and in conjunction with alum for dyeing woollen, linen, and cotton materials. The colour is fast and particularly brilliant. From Kurrer's observations onion skins are very suitable for dyeing cotton, on which they give a cinnamon-brown with acetate of alumina, a fawn with alumina and iron, a grey with iron salts, and a variety of shades with other additions."

The colouring matter was extracted by boiling the skins with distilled water for one hour, and the yellow extract on keeping gradually deposited the impure dye as a pale olive precipitate. The average yield was 1.3 per cent. This was extracted with alcohol, the concentrated extract treated with ether and the ethereal solution washed, until a tarry precipitate no longer separated. On extracting the ethereal solution with dilute alkali the whole of the colouring matter was removed, and on neutralising the alkaline liquid a yellow precipitate was thrown down, which was purified by crystallisation from dilute alcohol. The acetyl compound melted at 190-191°, and there could be no doubt as to the identity of this colouring matter with quercetin (Perkin and Hummel, Chem. Soc. Trans., 1896, 69, 1295). Attempts to isolate a quercetin glucoside from onion skins have hitherto failed, and it seems that such a compound is absent at least in the outer dry material.

Sophora japonica(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.

Sophora japonica (Linn.). This is a large and beautiful tree, not unlike an acacia, belonging to the Leguminosæ, which grows abundantly throughout China.

The undeveloped flower-buds constitute an important yellow dyestuff employed by the Chinese for colouring the silken vestments of the mandarins. For this purpose the buds are collected and dried rapidly, either in the sun or by artificial means, usually with the addition of a little chalk. The method of dyeing consists in simply boiling for one to one and a half hours in a decoction of the flower-buds silk which has been previously mordanted by steeping overnight in a.decoction of alum. Less frequently it is employed in the dyeing of cotton and wool. Its price appears to be about 305. a cwt.

This dyestuff has been studied by many chemists, especially by Schunck (Chem. Soc. Trans., 1888, 53, 262; 1895, 67, 30), who has proved that the glucoside which it contains, formerly called sophorin (Forster, Ber., 1882, 15, 214), is in reality identical with rutin, the quercetin glucoside first isolated from rue (Ruta graveolens, Linn.) by Weiss (Chem. Zentr., 1842, 903). (Cf. also Stein, J. pr. Chem., (i.), 58, 399; 85, 351; 88, 280; Schunck, Manchester Memoirs, 1858, 2 Ser., 15, 122.) The glucoside is readily isolated by extracting the flower buds with boiling water. The liquid on cooling deposits crystals of rutin, which can be purified by recrystallisation from water or dilute alcohol.

When applied to wool the Sophora japonica buds give colours somewhat like those obtained with quercitron bark, viz. a dull orange with chromium, a yellow of moderate brilliancy with aluminium, a bright yellow with tin, and a dark olive with iron. In dyeing power it seems to be equal if not slightly superior to quercitron bark, and is to be regarded as an excellent natural dyestuff, quite equal to those of similar character in general use (Hummel and Perkin, J. Soc. Chem. Ind., 1895, 458).