The constitution of chaulmoogric and hydnocarpic acids / by Marmaduke Barrowcliff and Frederick B. Power.
- Barrowcliff, Marmaduke.
- Date:
- [1907]
Licence: In copyright
Credit: The constitution of chaulmoogric and hydnocarpic acids / by Marmaduke Barrowcliff and Frederick B. Power. Source: Wellcome Collection.
5/26 page 559
![tricarboxylic acid, C1SH3206, were again produced, and, in addition to these, a keto-dicarboxylic acid, Cl7H30Or) (in. p. 128°), identical with the acid of this formula described in the previous communication (loc. cit.). When this keto-acid is oxidised in alkaline solution with an amount of potassium permanganate equivalent to three atomic proportions of oxygen, the principal product is n-dodecanedicarboxylic acid, which is ap¬ parently associated with a small quantity of w-undecanedicarboxylic acid. The constitution of this keto-acid may therefore be represented by the formula 00aH'[CH2]2-;-C0'[CH2]12-C02H, oxidation taking place principally at the place indicated by the dotted line with the production of n-dodecanedicarboxylic and malonic acids, and also, to a much less extent, at the other side of the carbonyl group, yielding w-undecane- dicarboxylic and succinic acids. The amount of succinic acid formed was not sufficient to permit of its identification, but malonic acid, as already stated, has been identified as a product of the oxidation of chaulmoogric acid with an excess of permanganate. The extreme ease with which this keto-acid is broken down by alkaline permanganate doubtless accounts for the fact that no appreciable amount of it could be isolated from the products afforded by the oxid ition of chaulmoogric acid with this reagent. By the addition of hydrogen bromide to ethyl chaulmoograte, ethyl bromodihydrochaulmoograte is formed, which is optically active, having [a]D + 3'88°. When the latter ester is reduced with zinc dust and acetic acid it gives ethyl dihydrochaulmoograte, Cl7H33*C02Et (m. p. 17°), which is optically inactive. It would therefore appear that the asymmetry of the chaulmoogric acid molecule is destroyed when the ethylenic linking is resolved by the addition of two atoms of hydrogen. When the elements of hydrogen bromide are split off from ethyl bromo¬ dihydrochaulmoograte the original ester is not regenerated, but a pro¬ duct is obtained which has a rotatory power of about + 7J30' in a 1-dcm. tube. The latter ester, on hydrolysis, afforded a mixture of acids, from which, on oxidation with permanganate, a ketodicarboxylic acid, C18II3205 (m. p. 126°), was obtained. A consideration of the results recorded in this communication renders it evident that the constitution of chaulmoo<nic acid cannot O be represented by any single formula. In the first place, by its limited oxidation, it yields two dihydroxy-acids, and, furthermore, when moro completely oxidised, two series of products are obtained. These pro¬ ducts are, on the one hand, a stable tricarboxylic acid, C1SH3206, and, on the other, formic acid and a ketodicarboxylic acid, C02H-[CH2]2-C0-[CH2]12-CO2H, the latter, by further oxidation, yielding zi-dodecane and ?i-undecane- dicar boxy lie acids.](https://iiif.wellcomecollection.org/image/b30611751_0005.jp2/full/800%2C/0/default.jpg)
