The petroleum extract was a dark-green, fatty solid; the ether and chloroform extracts were of a resinous character, and also possessed a darkgreen color; the portion removed by ethyl acetate was similar to the two preceding extracts, but of a somewhat lighter color; the alcohol extract was a dark-brown, syrupy mass. No crystals could be observed in any of these products. The dried marc was subsequently extracted with boiling water, and the liquid thus obtained, which possessed a slightly bitter taste, was found to give a dark-green coloration with ferric chloride and a dense yellow precipitate with basic lead acetate; it apparently contained a little tannin, together with gum and coloring matter. For the purpose of a complete examination, 96 pounds (43545 Gm.) of the air-dried eriodictyon leaves were thoroughly extracted by continuous percolation with hot alcohol. After the removal of the greater portion of the alcohol, 4434 pounds (20298 Gm.) of a thick, dark-green extract were obtained, corresponding to 46.6 per cent. of the weight of the leaves. 1000 Gm. of the alcoholic extract just mentioned were brought into a large flask, some water added, and steam then passed through the mixture until the entire amount of volatile substances present had been removed. Examination of the Steam Distillate. This liquid had an acid reaction, and contained a small amount of an essential oil. It was extracted three times with ether, the ethereal liquid washed, dried with anhydrous sodium sulphate, and the ether removed. The residue was a mobile, yellow oil, which possessed the characteristic odor of the drug. The amount obtained was 2.25 Gm., corresponding to 0.1 per cent. of the weight of air-dried leaves. It was distilled under atmospheric pressure, when it boiled between about 150 and 245° C., the greater portion, however, passing over below 190° C. This essential oil was readily soluble in 70 per cent. alcohol, and had the following constants: d=0.9372 at 15°/15° C. and a -0°.24' in a 25 Mm. tube. = The acids contained in the aqueous distillate from which the essential oil had been removed were converted into their barium salts for the purpose of identification. They were thus found to consist of formic and acetic acids, the former preponderating. Non-volatile Constituents of the Alcoholic Extract. After the removal of the volatile constituents, by distillation in steam, as above described, the contents of the distilling flask consisted of a brown, aqueous liquid and a large cake of soft, green resin, which had separated at the bottom. The aqueous liquid was decanted while hot, and, after adding a further quantity of water to the residual resin, steam was again passed into the mixture until it became heated to the boilingpoint. The flask was then placed in a bath of boiling water, and, after the green resin had been allowed to settle, the supernatant, aqueous liquid was decanted as before. This contained a small quantity of a semi-solid, bright yellow substance in a state of fine division, together with a small amount of the green resin. A further quantity of water was subsequently added to the resin, and the preceding oparation repeated. The first aqueous liquid which had been decanted from the resin, as above described, was allowed to cool, when it deposited a quantity of the same semi-solid, bright yellow substance as was contained in the liquids from the subsequent washings of the resin. All these aqueous liquids were allowed to stand for some time, when the substance in suspension gradually subsided to the bottom of the vessel. The clear portion of the liquid was then decanted, and the remainder separated as completely as possible from the precipitate by filtration. In this manner the following products were obtained: A clear, brown, aqueous liquid (A); a quantity of a slimy, semi-solid, bright yellow substance (B), which contained a few particles of green resin, and the previously mentioned large cake of green resinous matter (C). Examination of the Aqueous Liquid (A). This clear, aqueous liquid was concentrated to a small bulk on a waterbath, but, on cooling, nothing further separated. It was then repeatedly extracted with ether until nothing more was removed, and the ethereal liquid, after being washed with a little water, shaken with successive portions of a saturated solution of sodium carbonate. The alkaline liquid obtained by treatment with the first portion of carbonate solution (about 30 Cc.) was clear and of a brown color. This was acidified with sulphuric acid, and extracted with ether, the ethereal liquid being subsequently washed, dried, and the ether removed. Several grams of a deep yellow, sticky, varnish-like substance, possessing a strong sour smell, were thus obtained, but nothing of a crystalline character could be separated from it. The second and third extractions of the original ethereal liquid with sodium carbonate solution afforded intensely yellow liquids, containing a considerable quantity of a crystalline substance in suspension, which will subsequently be described. As these two aqueous, alkaline liquids appeared to be similar in character, they were mixed and filtered for the purpose of further examination. Isolation of a New Phenolic Substance, Eriodictyol, C15H12O6. The clear alkaline filtrate from the above-mentioned crystalline substance was at first of a deep yellow color, but rapidly became brown, which was apparently due to the absorption of atmospheric oxygen. It was at once acidified with sulphuric acid, extracted several times with ether, and the ethereal liquid washed, dried, and evaporated. Before all the ether had been removed, the contents of the flask became for the most part solid, and apparently crystalline. The solid thus obtained was first drained on a porous tile, and, after having been freed from a small amount of a bright yellow, varnish-like substance by washing with warm ether, it was obtained in the form of a brown powder. This substance was dissolved in hot alcohol, the solution boiled with animal charcoal, filtered, and concentrated on a water-bath, when the greater portion separated in small, glistening spangles of a light fawn color. After being collected on a filter, and dried, it was found to melt, with decomposition, between 260 and 270° C. When crystallized from glacial acetic acid, it was obtained in the form of small, fawn-colored plates, which darkened and melted to a red liquid at 267° C. C = = 4.3 0.1100 gave 0.2529 CO, and 0.0422 H2O. 62.7; H 0.1170 gave 0.2672 CO, and 0.0456 H,O. C 62.3; H 4.3. A portion of the substance was then recrystallized from boiling alcohol, when the melting-point remained unaltered. It was again analyzed with the following result: 0.0974 gave 0.2231 CO, and 0.0385 H2O. C = 62.5; H C15H12O6 requires C = 62.5; H = 4.2 per cent. 4.4. This substance is not identical with any compound hitherto described, and as its properties indicate that it 'is of a phenolic nature, and not a true acid, it is proposed to designate it eriodictyol. Eriodictyol is moderately soluble in hot alcohol and in acetic acid, very sparingly soluble in boiling water, and insoluble, or very sparingly soluble, in the other organic solvents. It dissolves readily in the fixed alkalies and alkali carbonates, affording at first almost colorless solutions, but which rapidly absorb oxygen and assume a deep brown color. When to a dilute solution of eriodictyol in water or in dilute alcohol a drop of ferric chloride solution is added, a deep greenish-brown color is produced, which rapidly changes to a pure brown. A saturated aqueous solution of eriodictyol does not reduce Fehling's solution, and is not appreciably precipitated by a solution of normal lead acetate, but with basic lead acetate it affords a bulky, yellow precipitate. Acetyl Eriodictyol.-A small quantity of eriodictyol was dissolved in an excess of hot acetic anhydride, and the mixture boiled for six hours. The greater part of the anhydride was then removed by distillation, and a small quantity of alcohol added, when, after standing for some time, a solid substance separated. This was collected on a filter, and recrystallized from ethyl acetate, when it was obtained in small tufts of minute, nearly colorless needles, which melted at 195-196° C. The amount of eriodictyol obtained from 1000 Gm. of the alcoholic extract of the drug was about 5 Gm., which corresponds to 0.23 per cent. of the weight of air-dried leaves. The crystalline substance separated by filtration from the aqueous alkaline liquid which afforded the eriodictyol, as previously described, was spread on a porous plate and allowed to dry. As thus obtained, it dissolved with moderate facility in boiling water, and, on cooling the solution, it separated in glistening, leaf-like crystals, possessing a beautiful silky lustre. After several recrystallizations from water, it was obtained perfectly white, and was evidently the sodium derivative of some organic substance of an acidic nature. The aqueous solution of this compound had a faintly alkaline reaction and a slightly yellow color, which was much intensified on the addition of an excess of alkali. A quantity of the above-mentioned sodium derivative was dissolved in hot water, dilute acetic acid added so long as a precipitate was produced, and the liquid allowed to cool. The pale-yellow, crystalline substance which separated was collected on a filter, washed with water, and dried, when it melted at 223° C. This substance was subsequently dissolved in boiling 70 per cent. acetic acid, when, on cooling, it separated from the solution in handsome, lemon yellow plates, which were likewise collected on a filter, washed with water, and dried. As its melting-point remained unchanged after this treatment, it apparently represented a pure substance. It was analyzed with the following result: 0.0977 gave 0.2267 CO, and 0.0424 H2O. 0.1156 gave 0.2686 CO, and 0.0493 HO. C=63.3; H=4.8. CHO requires C=63.5; H=4.6 per cent. A portion of this substance was dissolved by boiling with water and sodium bicarbonate, and the solution cooled. The crystalline sodium derivative which separated was collected on a filter, washed with water, and allowed to dry in the air. 0.1794 of the air-dried sodium derivative, when heated at 115° C. until of constant weight, lost 0.0361 or 20.1 per cent. C16H1306 Na,5 H2O requires H2O=21.7 per cent. 0.1433 of the anhydrous compound gave on ignition 0.0238 NaCO3. Na=7.2. CHO, Na requires Na-7.1 per cent. The fact that the sodium compound effloresces slightly on exposure to the air, would account for the somewhat low percentage of water found. From the above analytical results it is evident that the substance melting at 223° C. is correctly represented by the formula C16H1O. The only known substance of this formula which has properties at all agreeing. with those of the substance just described is hesperitin, which melts at 226° C. Although the melting-points of these two compounds are almost identical, there are other important differences which lead to the conclusion that the substance which we have isolated from eriodictyon, having the melting-point of 223 C., is not hesperitin, but an isomeric com pound of a similar type. The differences referred to may be summarized as follows: Hesperitin has been described as crystallizing in almost colorless needles, which possess an intensely sweet taste, and dissolve in alkalies with, at the most, a faintly yellow color.* The compound from eriodictyon, on the other hand, crystallizes in pale yellow plates, which have only a slightly sweetish taste, and dissolve in alkalies with a bright yellow color. Furthermore, hesperitin affords a sodium derivative of the formula C16H13O6Na.C16HО,† whereas the sodium derivative of the compound from eriodictyon, when prepared under the same conditions, has been shown to have the normal formula C1H1ОNa. As the formula of the compound melting at 223° C. differs by the increment of CH, from that of the other newly isolated substance, eriodictyol, it is proposed to designate it homo-eriodictyol. 14 Homo-eriodictyol resembles eriodictyol in solubility, but it is even more sparingly soluble in water than the latter, and apparently more readily soluble in alcohol and in acetic acid. When to a dilute alcoholic solution of homo-eriodictyol a drop of ferric chloride solution is added, an intense red-brown color is produced. An aqueous solution of homo-eriodictyol is not appreciably precipitated by either normal or basic lead acetate solution. Acetyl and benzoyl homoeriodictyol were prepared, but all the attempts to obtain these compounds in a crystalline condition were unsuccessful. A considerable amount of homo-eriodictyol was also obtained from other products of the drug, as will subsequently be noted. The total yield of this substance from 1000 Gm. of the original alcoholic extract was about 65 Gm., which corresponds to 3 per cent. of the weight of airdried leaves. The ethereal liquid from which the eriodictyol and homo-eriodictyol had been extracted by sodium carbonate solution was subsequently shaken with further quantities of the alkali until nothing more was removed, and it was then found that practically nothing remained dissolved in the ether. The alkaline liquids from these final extractions with sodium carbonate solution were acidified, and shaken out with ether in the usual manner, but they only afforded a small amount of uncrystallizable resinous matter. The aqueous liquid (A), from which the mixture of the above-described products had been removed by shaking with ether, had a brown color, and afforded a voluminous precipitate of a bright yellow color on the addition of a solution of basic lead acetate. A slight excess of the latter was therefore added, the resulting precipitate collected by filtration under pressure, washed with a little water, then suspended in water, and completely decomposed by hydrogen sulphide. The liquid containing lead sulphide was then heated to the boiling-point, filtered, and the filtrate *Journ. Chem. Soc., 1898, 73, p. 1032. + Ibid, 1898, 73, p. 1037. |