The constitution of chaulmoogric and hydnocarpic acids / by Marmaduke Barrowcliff and Frederick B. Power.

  • Barrowcliff, Marmaduke.
Date:
[1907]
Catalogue details

Licence: In copyright

Credit: The constitution of chaulmoogric and hydnocarpic acids / by Marmaduke Barrowcliff and Frederick B. Power. Source: Wellcome Collection.

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    Chaulmoogric acid has, however, all the properties of an individual substance. It has, moreover, been obtained from the seeds of three botanically distinct species of plants, and in all cases it possesses identical properties. In addition to this, a homologue of it, hydnocarpic acid, C16H2802, has been isolated (Trans., 1905, 87, 888), which shows an analogous behaviour on oxidation, and, like chaulmoogric acid, has all the characters of an individual substance. For these reasons it cannot be considered possible that chaulmoogric acid is a mixture of stable isomerides, and it must therefore be regarded as being in a state of tautomerism between the two formulae represented above, or at all events existing in such a state as to undergo chemical change in accordance with both these formulae. This conclusion respecting the constitution of chaulmoogric acid may also be expressed by a formula analogous to that propo-ed by Thorpe for glutaconic acid (Trans., 1905, 87, 1669) as follows : CH ch2—ch2 In this formula the dotted lines represent a state of equilibrium between the hydrogen atom and two carbon atoms. The results obtained by Sir W. H. Perkin for the molecular magnetic rotation of ethyl chaulmoograte, as previously recorded (Trans., 1904, 85, 851), are quite in harmony with the above conclusion. The average value found at 14° (21*02) lies between that calculated for the ester if it possessed the pentene structure (21*31) and that for the bicyclic structure (19*51). Sir W. II. Perkin has now kindly determined the rotation of ethyl chaulmoograte at a higher tempera¬ ture, when for a rise of 68*6° a diminution of 0*231 in the molecular magnetic rotation was observed, but as a small reduction with rise of temperature is usual amongst such compounds no deduction can be drawn from this observation. A determination of the molecular magnetic rotation of chaulmoogric acid at 84° gave a result analogous to that obtained for its ethyl ester, inasmuch as the value found (19*031) lies between the numbers calculated for the two formuke suggested for this acid. Hydnocarpic acid, C](;H280., (m. p. 60°; [a]D +68°), the isolation of which has previously been described (Trans., 1905, 87, 884), is a homo¬ logue of chaulmoogric acid, and is associated with the latter in the three fatty oils from which it has been obtained. The two acids are in every respect similar in their properties, and are evidently of closely analogous constitution. From a consideration of the constitutional formulae assigned to chaulmoogric acid it was to be expected that hydnocarpic acid would
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