The constitution of umbellulone. Pt. III / by Frank Tutin.

  • Tutin, Frank.
Date:
1908
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: The constitution of umbellulone. Pt. III / by Frank Tutin. 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.

    10/12 (page 259)
    obtained by him melted at 150°, and was evidently the above-described mixture. The foregoing results may be summarised as follows: The umbellulone obtained by the fractional distillation of the essential oil of Californian laurel is not the pure ketone, C10H14O, but, on analysis, gives results agreeing with those yielded by a mixture of substances, C10H14O and C10H16O. When this umbellulone fraction is reduced, it gives about 70 per cent, of its weight of an unsaturated mixture of alcohols, C10H16O and c10h18o. On oxidising this mixture of alcohols, the former one is readily destroyed by the excess of the oxidising agent, and less than a 50 per cent, yield of a ketonic product (“ /3-dihydroumbellulone ”), C10HlfiO is obtained. The explanation of this appears to be that the original fraction of the oil is a mixture of ketones, C10HuO and C10H16O, which, on reduction, yields the corresponding alcohols, that is, umbellulol and a product, C10H17*OH. This conclusion is in agreement with the unsaturated character of the material. On treating this mixture with chromic acid, the umbellulol is broken down, and “ /3-dihydro- umbellulone ” is obtained from the product, C10Hl7*OH, from which consideration it appears highly probable that “ /3-dihydroumbellulone ” is not a derivative of the ketone from which it was named.* Finally, this “ /3-dihydroumbellulone ” is a mixture of at least two ketones, one of which is saturated, and one unsaturated. It was from a constituent of this mixture of unknown origin that Semmler prepared homotanacetonedicarboxylic acid, and such is the foundation upon which he has based his conclusions respecting the constitution of umbellulone. Apart from the above considerations, Semmler represents “ /3-di- liydroumbellulone ” as umbellulone in which the double linking has been reduced. This view, however, could not possibly be correct, even if “ /3-dihydroumbellulone ” were a definite derivative of um- bellulone, since a-dihydroumbellulone (m. p. of semicarbazone 177°), a compound which is certainly a pure, saturated derivative of umbellulone, must be represented in this manner. a-Dihydro- umbellulone is not only formed by the reduction of monobromo- umbellulone (Lees, Trans., 1904, 85, 639), but can also be obtained by the reduction, with zinc dust and acetic acid, of umbellulone dibromide, the initial product of the interaction of bromine and umbellulone at 0°. * With llio exception of “ £-dihydroumbellulone,” all compounds described by Power and Lees, by Lees, or myself as derivatives of umbellulone have been proved to be derived from this ketone.