Chemical examination of Ipomoea purpurea / by Frederick B. Power and Harold Rogerson.

  • Frederick Belding Power
Date:
[1908?]
Catalogue details

Licence: In copyright

Credit: Chemical examination of Ipomoea purpurea / by Frederick B. Power and Harold Rogerson. Source: Wellcome Collection.

    34/40 (page 32)
    from the so-called purgic acid, a product of the alkaline hydrolysis of “ convolvulin” by treatment with dilute sulphuric acid. As Hoehnel, however, did not record the melting point of his acid, and the amount of acid obtained by us having been too small to permit of the preparation of the derivatives described by him, it is impossible to decide whether the two substances are identical. Guerin1 has synthesized a-hydroxylauric acid, the melting point of which is stated to be 73-74° C. As Guerin had prepared an anilide of this acid (m. p. 83° C.), a little of the corresponding derivative was made from the acid obtained by us for the purpose of comparison, the method employed having been precisely the same as that adopted by Guerin. A product was obtained in the form of small, lustrous plates, which melted at 15 5-157° C. It is, therefore, evident that the hydroxylauric acid obtained from Ipomoea purpurea is not the alpha compound. An attempt was made to obtain an acetyl derivative of the above- described acid, but the product was an oil, which did not solidify. {b) Ether Extract.—This constituted the remainder of the solid product obtained from the alcohol extract of the hydrolyzed resin. After purification it was found to consist entirely of ipurolic acid, C14H2804, which had previously been obtained by the treatment of the alcohol extract of the original resin with dilute sulphuric acid. On analysis it gave the following result: 0-2228 gave 0 5280 CO., and 0 2146 H20. C = 64-6; H — 10-7. Ci4H2804 requires C = 64-6; H = IO-8 per cent. The acid liquid, from which the above-mentioned crystalline acids had been separated, was treated with baryta for the removal of the sulphuric acid, and, after filtration, diluted to the measure of 1 litre. This liquid readily reduced Fehling’s solution on heating, and yielded an osazone which, after crystallization from pyridine, melted at 212-2130 C., and was therefore nf-phenylglucosazone. A quanti¬ tative determination, by means of Fehling’s solution, of the amount of sugar, formed by the action of dilute sulphuric acid on the alco¬ hol extract of the hydrolyzed resin, indicated that 25 grammes of the latter had yielded 4-3 grammes of glucose. If the amount of crystalline acid (5-5 grammes), consisting essentially of ipurolic 1 Bull. Soc. chim., 1903 [3], 29, 1124-1128, aud Journ. Client. Soc., 1904, 86, Part I, p. 138.