A laevo-rotatory modification of quercitol / by Frederick B. Power and Frank Tutin.

  • Power, Frederick B. (Frederick Belding), 1853-1927
Date:
[1904.]
Catalogue details

Licence: In copyright

Credit: A laevo-rotatory modification of quercitol / by Frederick B. Power and Frank Tutin. Source: Wellcome Collection.

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    LX1I.—A Lcevorotatory Modification of Quercitol. By Frederick Bklding Power and Frank Tutin. Quercitol has hitherto only been found in the fruits (acorns) of certain species of Quercus, in which it exists as a dextrorotatory modification. The lcevorotatory modification now described was obtained by us from the leaves of Gymnema sylvestre (Br.), a plant belonging to the family of Asclepiadacece, and indigenous to Banda and the Deccan Peninsula (compare “ Pharmacographia Indica,” vol. II, p. 450). In the course of an examination of a large quantity of Gymnema leaves, a colourless, crystalline substance having the empirical formula C6Hu06 was isolated, which melted at 174° and had [a]D -73*9°. When heated at 110°, it lost one molecular proportion of water; it formed a penta-acetyl derivative, C6H7(0*C2H30)5, and a pentabenzoyl derivative, C6H7(0*C7H50)5. From these facts it was seen that the above formula, C6H1406, could be appropriately modified to 06li7(0H)5,H20, which represents the substance as a hydrated isomeride of quercitol. The constitutional formula of quercitol, first proposed by Kanon- nikoff, represents it as pentahydroxyhexahydrobenzene, HO-HC CH-OH HO-HC CH-OH CH-OH The correctness of this formula was proved by Kiliani and Schaefer (Her., Ib96, 29, 1762), who obtained malonic acid on oxidation with potassium permanganate. Moreover, the same investigators have shown that (/-quercitol, on oxidation with aqueous bromine, forms a diketone, Ct;H805, which was isolated in the form of its dihydrazone, ^18^20^3^4* The substance isolated from the leaves of Gymnema sylvestre, when oxidised with potassium permanganate and sodium hypobromite respectively, showed a behaviour identical with that of (/-quercitol. Like the latter, it afforded, on the one hand, malonic acid, and, on the i other, a diketotrihydioxyhexahydrobenzene, which was isolated in the 11 form of its dihydrazone (m. p. 209°). It was thus demonstrated that our substance has the same con- l stitution as> (/-quercitol, and can only differ from the latter stereo