The organic constituents of plants and vegetable substances and their chemical analysis / by G.C. Wittstein ; authorised translation from the German original, enlarged with numerous additions, by Baron Ferd. von Mueller.

  • Georg Christian Wittstein
Date:
1878
Catalogue details

Licence: Public Domain Mark

Credit: The organic constituents of plants and vegetable substances and their chemical analysis / by G.C. Wittstein ; authorised translation from the German original, enlarged with numerous additions, by Baron Ferd. von Mueller. Source: Wellcome Collection.

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    täte the filtrate with acetate of lead, treat the deposit with diluted acetic acid, filter, heat the filtrate to boiling point and precipitate with siibacetate of lead. Decompose the deposit under water with sulphuret of hydrogen and evaporate the filtrate in a current of «arbonic acid gas.—Amber-yellow powder of an acidulous, acerb taste, greens the salts of oxyd of iron, separates on heating with <liluted acids a red-yellow powder (Rhodoxanthin~2 C14 H7 Og + HO). KlloeH(lin=C42 H21 NO12. Peculiar alkaloid occurring in all parts of Papaver Rhoeas and allied species. Treat the whole herb with warm water, concentrate the extract, oversaturate with car- bonate of soda and shake repeatedly with ether. Transfer the Rhoea- din from the ethereous solution to an aqueous solution of bitartarate of soda by shaking, throw away the ether and precipitate the aqueous liquid with ammonia, wash the deposit, dry, and boil with alcohol, in order to remove dyeing matters and an alkaloid which exists in the plant in small quantity only, and seems to be thebain. The Phoeadiii remains by this process for the greatest part undissolved. To pmify it completely, dissolve the remnant in acetic acid, shake with animal charcoal and precipitate with ammonia.—Forms small, white prisms, tasteless either by itself or in solution; fuses at 232° without loss of weight, becomes brown and sublimates ])artly; is almost insoluble in ether (in 1280 parts), benzol, chloroform, alcohol, water, liquor of ammonia, soda-ley and lime-water; the alcoholic solution has a scarcely perceptible alkaline reaction. Dissolves in acids, without being able to neutralise them or even to remain in contact with them without alteration (to turn red), especially hydrochloric and sulphuric acids, yielding purple-red solutions. Alkalies restore the original colour. The red coloura- tion is accompanied by the production of a colouring substance, and of a new alkaloid of highly basic properties and of the same composition as Phoeadin. Concentrated sulphuric and nitric acids dissolve the Phoeadin under decomposition, the former acid with olive-gi-een, the latter with yellow colour. The colourless solution of Ph. is precipitable by tannin, chloride of mercury, etc. RllOitaimic Acid = Cig Hu O13. In the leaves of Rhus Toxicodendron. Shake the ethereous extract with warm water, filter, allow to rest for two days, filter anew, throw do^vn sulphuric and phosphoric acids by means of a little acetate of lead, filter and precipitate completely with acetate of lead, decompose the latter deposit under water with sulphuret of hydrogen; filter and evaporate.—Amorphous, yellowish-green, gum-like mass, of slightly bitter taste and acidulous reaction, colours and precipitates the salts of oxyd of iron dark green, colours tartarated antimony dark yellow without precipitation, turbidifies solutions of glue when concentrated.