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.

    15/20 page 302
    rhubarb by Schlossberger and Dopping, is strictly correct, since the latter product was really a mixture of chrysophanol and emodin Percentage in Percentage in Percentage Constituent. sample A. sample B. in sample C. Chrysophanol. \ * Emodin monomethyl ether . j 6-3 7-2 8-9 Crude chrysophanolanthranol. about 26‘0 about 46‘0 about 62*0 Anthranol of emodin monoinethyl ether small small small Monomethyl ether of dehydroemodin- amount amount amount anthranol . 41T 13-4 17-7 Ararobinol . 4-2 4-1 nil Emodin . Inseparable mixture of substances and trace nil nil amorphous matter. about 23*0 about 30’0 about 12'0 * About 3 or 4 parts of the former to 1 of the latter. monomethyl ether similar to that occurring in chrysarobin (compare Trans., 1911, 99, 946). The amount of “ chrysophanic acid” indi¬ cated by Attfield to be contained in chrysarobin was, however, much greater than that actually present. Jowett and Potter (loc. cit.), who fully considered the work of Liebermann and Seidler (.Ber., 1878, 11, 1603), of Liebermann (ibid., 1881, 21, 437; Annalen, 1882, 212, 41), and of Hesse (ibid., 1899, 309, 32), stated that they had isolated from commercial chrysarobin the following substances: Chrysophanolanthranol (“ chrysarobin ”), “ dichrysarobin,” “ dichrysarobin methyl ether,” and a substance, C]7H1404. In the present investigation we have confirmed the statement regarding the presence of the anthranol, but could obtain none of the other three compounds. With regard to the substance C17H1404, we can only say that no compound of this composition could be detected by us in any of the products examined. With regard to “ dichrysarobin ” and its “ methyl ether,” however, the experience gained during the present work led us to doubt their homogeneity; for instance, during this investigation a product was obtained which appeared to possess all the attributes of homo¬ geneity, and which agreed approximately in its composition and properties with the “ dichrysarobin methyl ether ” of Jowett and Potter. It was found, however, to be a mixture of chrysophanol¬ anthranol and the monomethyl ether of dehydroemodinanthranol, for, when subjected to a carefully regulated treatment with chromic acid, the anthranol alone was oxidised, and the resulting chryso¬ phanol was then readily separated from the monomethyl ether of dehydroemodinanthranol. (Jow^ett and Potter found for “ dichrys¬ arobin methyl ether,” C = 73 0; H=4'9; CH3 = 21 per cent.; m. p. 160°. A mixture of equal parts of chrysophanolanthranol and the monomethyl ether of dehydroemodinanthranol melts at about 170°, and requires C = 73'3; H = 4‘8; CH3 = 2'9 per cent.) Now, the above-described mixture, on treatment with hydriodic
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