Some derivatives of umbellulone / by Frederic H. Lees.

  • Lees, F. H. (Frederic Herbert)
Date:
[1904.]
Catalogue details

Licence: In copyright

Credit: Some derivatives of umbellulone / by Frederic H. Lees. Source: Wellcome Collection.

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    umbellulone, C10H15OBr, can only be explained on the assumption that one of the two closed rings present in umbellulone, dibromo- dihydroumbellulone, and bromodihydroumbellulone becomes resolved by reduction in passing to the alcohol. Umbellulone is readily oxidised by cold permanganate, yielding a lactone, C()H1.,02 (b. p. 217—221°), together with several acids which, on account of insufficiency of material, have not yet been investigated. Experimental. Action of Bromine on Umbellulone. Formation of Umbellulone Dibromide, C10H14OBr2. Twenty grams of umbellulone were dissolved in 100 c.c. of dry chloroform, and the solution cooled in a freezing mixture. A solution of 25 grams of dry bromine in 100 c.c. of dry chloroform was then run in, drop by drop ; the bromine was instantaneously absorbed, and without any evolution of hydrogen bromide. When all the bromine had been added, the colour of the solution was red, and on this remaining permanent for some minutes, the slight excess of bromine was removod by shaking the liquid with a solution of sodium hydrogen sulphite. The nearly colourless liquid, after washing several times with water, was dried with calcium chloride, and the chloroform removed by allowing the liquid to boil under diminished pressure without the application of external heat. The resulting dibromide was a somewhat dark, heavy oil, the amount obtained being ap¬ proximately equal to the combined weights of the umbellulone and bromine originally taken for its formation, thus showing that the process is one of addition and not of substitution. A portion was exposed in a vacuum desiccator over paraffin wax, and then analysed : 0 4554 gave 0‘528 AgBr. Br = 49*3. C10H14OBr2 requires Br = 51‘6 per cent. Umbellulone dibromide is very unstable, readily losing hydrogen bromide even when kept at the ordinary temperature. Action of Heaton Umbellulone Dibromide. Formation of an Unsaturated Bromohetone, C10iri2OBr, and Dibromodihydroumbellulone, C10H14OBr2. A quantity of umbellulone dibromide was slowly heated in a distilling apparatus under 20 mm. pressure. An energetic evolution of hydrogen bromide commenced almost immediately, and a small amount of a colourless liquid passed over into the receiver while the temperature was
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