Chemical examination of the root of Ipomoea orizabensis / by Frederick B. Power and Harold Rogerson.

  • Frederick Belding Power
Date:
1912
Catalogue details

Licence: In copyright

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

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    a copious, yellow precipitate was produced. This precipitate was collected, washed, and then suspended in water, and decomposed by hydrogen sulphide. On filtering the mixture, and concentrating the filtrate, a dark brown liquid was obtained, which gave a green colour with ferric chloride, but did not precipitate gelatin. After treating the liquid with a solution of potassium hydroxide, as previously described, a further small quantity of 3:4-dihydroxy- cinnamic acid was obtained. The filtrate from the precipitate produced by basic lead acetate was treated with hydrogen sulphide for the removal of the excess of lead, the mixture again filtered, and the filtrate concentrated under diminished pressure to the consistency of a syrup, which, on cooling, formed a viscid jelly. The syrup instantly reduced Fehling’s solution on heating, and yielded d-phenylglucosazone, melting at 205—206°. In order further to confirm the identity of the sugar, a portion of the syrup was heated with acetic anhydride in the presence of a little rf-camphorsulphonic acid. A crystalline acetyl derivative was thus obtained, which melted at 130—131°, and was identified as /3-penta-acetyldextrose. Inasmuch as the original alcoholic extract has been shown to contain a small amount of sucrose, which would doubtless have become inverted during the subsequent operations of heating, it is probable that the above- mentioned syrup, in addition to dextrose, also contained some laevulose. There was, however, no evidence of the presence of a methylpentose. A portion (50 grams) of the above-mentioned syrup was heated with 5 per cent, sulphuric acid, and the liquid extracted with chloro- form, when a very small amount (O'l gram) of scopoletin was obtained, thus indicating the presence of a glucoside of this substance. The attempts which were made to isolate a glucoside from the syrup were, however, unsuccessful. Examination of the Resin (B). The crude resin, which had been separated from the aqueous liquid (A) as previously described, formed a dark brown mass, which, when dry, could be reduced to a light brown powder, and when treated with a little animal charcoal was obtained nearly colourless. After drying in a vacuum over sulphuric acid, it melted at 125—130°. Optical Rotation of the Crude Resin. Since the optical rotatory power of the various convolvulaceous resins has been considered to be a factor of some value in deter-
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