The constitution of umbellulone. [Pt. I] / by Frank Tutin.

  • Tutin, Frank.
Date:
[1906]
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: The constitution of umbellulone. [Pt. I] / 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.

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    to the presence of oxidation products derived from substances other than umbellulone contained in the fraction of oil employed. When this mixture of acids is slowly distilled under 20 mm. pressure, water is eliminated, and a portion of the umbellulonic acid passes into an unsaturated lactone, C9IIJ2O2 (b. p. 129—135°/50 mm.), which, on solu- tion in potash, again yields the keto-acid. This lactone is, in fact, produced by the elimination of water from the enolic modification of umbellulonic acid. 00 OO2H ^ CO-CH, CO2H c(oh):ch2 Umbellulonic acid. Enolic modification. c:ch2 Lactone. H2O. The change from keto-acid to lactone also takes place, but to a less extent, when pure umbellulonic acid is distilled under diminished pressure. The explanation of the phenomenon, that a larger proportion of umbellulonic acid becomes converted into lactone on distilling the crude mixture of acids than when the pure acid alone is distilled, probably lies in the fact that the acids associated with the umbellulonic acid in the former case are of higher boiling point, and also give rise to anhydrides * which assist in the abstraction of water and formation of the lactone. This supposition receives support from the fact that umbellulonic acid was found to pass into the lactone on boiling with acetic anhydride. This unusual change from keto-acid into unsaturated lactone, and vice versd, is accompanied by a remarkable change in optical rotation, as the former has [a]n -t-377‘6° and the latter [a]i) -210-58'^. Fiom the formation of umbellulonic acid, CgH^9(C02H)C0*CH3, by the oxidation of umbellulone, CjqHj^O, it would appear that the latter contains the complex The lactone, when shaken into an emulsion with water, is readily oxidised by potassium permanganate, giving a quantitative yield of a polymethylene dicarboxylic acid, CgHj204 (m. p. 120—121°; [a]]) - 89'7°), for which the name umhellularic acid is proposed. CO CgHjo<^0 -b H2O -b 40 = ^ ^ o:ch2 The lactone. Umhellularic acid. Umhellularic acid passes into the anhydride (b. p. 167—169°/50mm.) when heated to about 150°, and is remarkably stable, for all further * Umbellularic acid is probably present.