The constituents of leptandra / by Frederick B. Power and Harold Rogerson.

  • Frederick Belding Power
Date:
[1910?]
Catalogue details

Licence: In copyright

Credit: The constituents of leptandra / by Frederick B. Power and Harold Rogerson. Source: Wellcome Collection.

    8/18 (page 1949)
    a large volitme of alcoliol was added, when a quantity of a crystalline substance was deposited, which was collected, washed with a little alcohol, and dried. The liquid from which this crys¬ talline substance had been separated was deprived of alcohol, and evaporated to the consistency of a syrup. It evidently contained a large amount of a sugar, since it readily reduced Fehling’s solution, and yielded <Aphenylglucosazone, melting at 209—211°. Isolation of d-Mannitol. The crystalline substance above described, which amounted to 120 grams, or 2T4 per cent, of the weight of the drug, was re¬ crystallised from alcohol, when it separated in needles, melting at 165—166°, and proved to be d-mannitol. (Found, C = 39*5; H = 7*8. Calc., C = 39'6; H = 7'7 per cent.) Further confirmation of the identity of the above-described substance with mannitol was obtained by the formation of its acetyl and benzoyl derivatives. On heating a little of the substance with acetic anhydride, a product was obtained which, when crystallised from absolute alcohol, separated in octahedra, melting at 122—124°, and consisted of the hexa-acetyl derivative of mannitol. Another portion of the substance was benzoylated by the Schotten-Baumann method, as employed by Panormoff (J. Russ. Phys. Ghtm. Soc., 1891, 23, 375), when a product was obtained which was soluble in chloroform, but, on the removal of the solvent, formed a syrup. On dissolving this, however, in a small volume of ether, it yielded a mass of needle-shaped crystals, which melted at 149°, and after recrystallisation from a mixture of ethyl acetate and alcohol, or from acetic anhydride, the melting point remained unchanged. (Found, C = 71*3; H = 4*9. Calc., C = 71*4; H = 4*7 per cent.) This substance is thus seen to be hexabenzoylmannitol, C6H806(C0 • C6H5)0, the melting point of which has been given as 149° by Skraup (Monatsh., 1889, 10, 389) and by Panormoff (loc. cit.), but was incorrectly recorded by Stohmann, Rodatz, and Herzberg (J. pr. Chem., 1887, [ii], 36, 354) as 124—125°. The optical rotatory power of hexabenzoylmannitol does not appear to have previously been recorded, and this was therefore determined, with the following result: 0*4238, made up to 20 c.c. with chloroform, gave aD + 2°9; in a 2-dcm. tube, whence [a]D +50*7°. If the benzoylation of mannitol is conducted in the usual manner, by adding the benzoyl chloride in small quantities at a time, a dibenzoyl derivative, C6H1206(C0*C6H5)2, is obtained. This is very