The determination of ascaridole in chenopodium oil / by H. Paget.

  • Paget, Humphrey.
Date:
[1925.]
Catalogue details

Licence: Public Domain Mark

Credit: The determination of ascaridole in chenopodium oil / by H. Paget. Source: Wellcome Collection.

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    the fact that ascaridole readily undergoes intramolecular change to ascaridole glycol anhydride (Formula II), and that this is easily hydrated, forming ascaridole glycol (Formula III). CH3 I C CH, OH CH„ CH, OH CH, C I c3h7 iv CH, CH, •a c CH I yC ch2 1 X 0 CH ch2 CH. ch2 CHOH 1 1 II - -> 1 0 1 0- -> 1 0 ch2 0 CH ch2 CH ch2 CHOH C I c8h7 c I QH7 II c I CsH? III These two changes occur in succession by the mere application to ascaridole of (a) dry heat, (b) steam, and it is clear that in the distillation with steam involved in the manufacture of the oil from the seed such changes must occur. In the course of work on the components of the oil the author has fractionally distilled many litres of it, and has invariably found evidence of such decomposition. The anhydride and the glycol are, like ascaridole, miscible with 60 per cent, acetic acid, and therefore rank as ascaridole when general tests of this kind are applied. Further, chenopodium oil commands a fairly high price, and is in consequence liable to adulteration, as in the case of the “synthetic” chenopodium oils to which Messrs. Schimmel and Co. have called attention in their Reports for 1919 and 1921, and one of the substances found in such oils—cineole—is also miscible with 60 per cent, acetic acid (see p. 7). Quantitative Reduction of Ascaridole.—It is therefore desirable that a method should be found by which ascaridole itself can be determined. In the work already referred to, the only method which has been found satisfactory is the isolation of ascaridole by distillation under reduced pressure, but, as ascaridole is liable to explode on the application of heat, this does not constitute a desirable process for general use. Formula I shows that ascaridole is a peroxide, and, like these substances in general, it forms no solid derivatives by which it can be isolated. Attention was therefore directed to the possibility of its quantitative reduction. It has long been known that in presence of ferrous sulphate ascaridole is converted into the corresponding glycol (Formula III), but, as will be seen from Formulae I, II and III, this is not a true reduction, but merely involves intramolecular change and hydration. Wallach (Annalen, 1912, 392, 60), however, has shown that hydrogen in presence of palladium reduces ascaridole to 1-4-terpin (Formula IV) by the addition of four atoms of hydrogen, and there therefore seemed a possibility of finding an agent which would effect such a change in a manner both quantitative
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