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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    After treatment with a little animal charcoal, the optical rotatory power of the resin was determined, with the following result: A solution in absolute alcohol, of which 5 c.c. contained 0 2072 gram of the resin, gave oD -0°51' in a 1-dcm. tube, whence [«]D -20-5°. Hydrolysis of the Ethereal Extract with Barium Hydroxide. A quantity (500 grams) of the dry ethereal extract of the resin was dissolved in alcohol, and, after the addition of a little water, a cold saturated solution of barium hydroxide waB gradually added until the liquid showed an alkaline reaction. It was then kept at a temperature of 35—45°, and the alkalinity maintained by the further occasional addition of small portions of solution of barium hydroxide. This treatment was continued until the liquid gave no turbidity when mixed with water, after which it was allowed to cool, and a dark brown precipitate which had formed during the hydrolysis was separated by filtration. Isolation of Ipuranol, C23H3802(OH)2. The above-mentioned dark brown precipitate amounted to 50 grams, and consisted for the most part of a barium salt. It was treated with acetic acid, when a portion remained undissolved, and this, after being dried, was extracted in a Soxhlet apparatus with absolute alcohol. A small amount of a sparingly soluble substance was thus removed, which, after several crystallisations from dilute pyridine, was obtained in colourless, microscopic needles, melting at 285—290°. After drying at 110°, it was analysed. (Found, C = 72'4 ; H = 10'6. Calc., C = 72'6; H = 10‘5 per cent.) This substance was evidently ipuranol, the identity of which was further confirmed by the colour reactions and the formation of the acetyl derivative, which separated from ethyl acetate in needles melting at 162°. The liquid from which the above-mentioned dark brown precipi- tate had been separated by filtration was diluted with a large volume of water, and distilled in a current of steam in order to remove the alcohol. The excess of barium was then removed by carbon dioxide, and, after boiling and filtering, dilute sulphuric acid was added to the liquid until a precipitate just ceased to be produced, any excess of the mineral acid being carefully avoided. The liquid was again filtered to remove the barium sulphate, and then distilled in a current of steam until volatile acids ceased to pass over.