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.

    9/12 (page 258)
    Since the “ dihydroumbellulol ” described by Semmler was prepared in the above manner, and from a portion of the identical oil employed by me, it would naturally be expected to consist of a similar mixture. It is stated to have had the following constants: d 20° = 0931 ; aD — 27°30' in a 1-dcm. tube, and, on analysis, gave C = 77-37 ; H = 11 22 per cent. These figures for the density and rotation are practically identical with those found by me, .as given above, but the analysis cannot be said to agree with any formula. It is evident, however, that Semmler’s preparation must have been essentially the same as that obtained by Mr. Lees and by the present author. Oxidation of the Reduction-product.—Fifteen grams of the above- described mixture of alcohols (see Trans., 1906, 89, 1118) gave, on oxidation with a chromic acid mixture, 6 grams of a product, boiling at 204—209°, which was designated “ /Ldihydroumbellulone.” This material, when dissolved in chloroform, readily decolorised a solution of bromine in the same solvent, and, on analysis, gave results in agreement with those required for the formula C10H16O. This was confirmed by analysis of the semicarbazone. Since 6 grams of a ketonic product, O10H1(JO, had been obtained by oxidising 15 grams of a mixture of unsaturated alcohols, C10H](JO and C10H18O, it was stated that the former alcohol must have been destroyed. The semicarbazone of this “ /3-dihydroumbellulone ” was prepared, and was first obtained in a viscous condition, but after standing for some time it became solid. It was then dissolved in alcohol and allowed to crystallise, when a product melting at 150° was obtained. On recrystallisation from a mixture of ethyl acetate and light petroleum, the melting point of this product was raised to 155—156°. This material has now been fractionally crystallised from ethyl acetate, when the melting point of the most sparingly soluble fraction gradually rose, and eventually about 30 per cent, of the product was obtained in well-defined needles, which were sparingly soluble in ethyl acetate, and melted sharply at 204°. The ketone regenerated from this semicarbazone (m. p. 204°) behaved towards bromine as a saturated compound, and is doubtless the substance which gave rise to Semmler’s benzylidene derivative. The more readily soluble portions of the semicarbazone, which formed the greater part of the material, gave a ketone which, when dissolved in chloroform, instantly decolorised a solution of bromine in the same solvent. The name “/3-dihydroumbellulone ” ought therefore to be discarded, since the preparation is a mixture. The “ /3-dihydroumbellulone ” prepared by Semmler had the same characters as the liquid which I had described under that name, but he failed to observe that the preparation is a mixture, consisting, to a considerable extent, of an unsaturated substance. The semicarbazone