The constituents of commercial chrysarobin / by Frank Tutin and Hubert W.B. Clewer.

  • Tutin, Frank.
Date:
[1912?]
Catalogue details

Licence: In copyright

Credit: The constituents of commercial chrysarobin / by Frank Tutin and Hubert W.B. Clewer. Source: Wellcome Collection.

    13/20 page 300
    of an intensely green liquid, from which nothing crystalline could be isolated. The chloroform, ethyl acetate, and alcohol extracts of the original solid (p. 291) amounted to 34, 1, and 3 grams respectively. They all consisted of black, amorphous products, and nothing crystalline could be obtained from any of them. II.—Examiruition of Commercial Samples of Chrysarobin. Three commercial samples of chrysarobin, which may be designated as A, B, and C respectively, were obtained from trust¬ worthy sources; sample A came from the same firm as had supplied the Araroba powder, the examination of which has just been described. It was found that a preliminary idea of the nature of the product might be obtained by estimating quantitatively the amount of oxygen absorbed by an alkaline solution of the material. Chryso- phanolanthranol, when air is passed through its solution in alkali, absorbs practically the theoretical amount of oxygen (13'3 per cent.) in about two hours. The monomethyl ether of dehydro- emodinanthranol, however, is oxidised much more slowly under similar conditions, and ararobinol also appears very slowly to absorb oxygen. Known weights of the various products were therefore dissolved in a weighed amount of aqueous potassium hydroxide in a suitable apparatus, and air passed through the mixture, the necessary precautions to ensure a quantitative deter¬ mination being taken. The following results were then obtained: Oxygen Oxygen Weight absorbed during absorbed during Material. takeu. first two hours. fifteen hours. Sample A . 0-9022 6 7 per cent. 11 0 per cent. „ B . 0-8816 7-4 10-7 „ c . Petroleum extract of 0-9596 5-1 10-1 Araroba powder. 1-9130 6-9 — Chrysophanolanthranol . 0-2340 12-8 — From these figures it would appear that none of the commercial products consisted essentially of anthranols or similar substances, as has been indicated by the work of previous investigators. A quantity (100 grams) of each of the samples, A, B, and C, was then mixed with purified sawdust, and submitted to prolonged extraction in a Soxhlet apparatus with petroleum (b. p. 35—40°), ether, and chloroform, when the entire amount of the material was removed. Although the extraction with petroleum was con¬ tinued for a number of weeks, no sharp separation was effected, for it was found that the same compounds were, in each case,
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