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.
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![When a dilute aqueous solution of chaulmoogric acid in an excess of potassium hydroxide is treatedat temperatures below 10° with an amount of potassium permanganate equivalent to one atomic proportion of oxygen, a considerable portion of the acid is recovered unchanged. This is due to the very sparing solubility of the potassium salt in water at low temperatures. If, however, an amount of permanganate equivalent to 2—3 atomic proportions of oxygen is employed at a temperature of 18—20°, two isomeric dihydroxydihydrochaulmoogric acids having the formula C18H3202(0H)2 can be isolated, whilst formic acid is also produced. The acid to which the name a-dihydroxydihydro- chaulmooyric acid may he applied melts at 105°, and has [a]D + IT6°. It is identical with the dihydroxy-acid previously described (Power and Gornall, loc. cit.). The isomeric acid, designated as /3-dihydroxydihydro- chauhnoogric acid, melts at 93°, and has [a]^ - 14'2°. On repeating the oxidation with the use of an amount of permangan¬ ate equivalent to four atomic proportions of oxygen, an acid of the formula C1SH3204 was produced. This was isolated in the form of its methyl ester, which had the composition C19H34G4, melted at 64°, and gave a semicarbazone melting at 110°. It thus appears that this is the methyl ester of a hydroxylcetodihydrochaulmoogric acid. On hydrolysis with alcoholic sodium hydroxide this ester neutralised two equivalents of the alkali, notwithstanding the fact that it is derived from a monocarboxylic acid. This property is probably due to the open¬ ing of the ring by the hydrolysis of the grouping *CH(OII)'CO, with the formation of the sodium salt of a hydroxydicarboxylic acid, ^18^34^5' The acid liberated from this salt was found to have the formula ^18^32^4’ but it did not again yield the original ester, and would therefore appear to be a lactonic acid, formed by the elimination of a molecule of water. By the oxidation of chaulmoogric acid in alkaline solution with an excess of permanganate, an amount of the latter equivalent to 6—7 atomic proportions of oxygen was consumed. A tricarboxylic acid (m. p. 68°), having the formula C1SH3.,0(;, was thus obtained, together with ?i-dodecanedicarboxylic acid, [CH2]12(C02H)2, a smaller quantity of n-undecanedicarboxylic acid, [CH2]n(C02H)2, and still smaller quantities of oxalic and malonic acids. The tricarboxylic acid is a very stable compound, and the numerous attempts to obtain from it such degradation products as would throw light on its constitution were unsuccessful. In order to ascertain whether the same products would be obtained under different conditions, an oxidation of chaulmoogric acid was con¬ ducted in acetic acid solution. The n-dodecanedioarboxylic acid and the](https://iiif.wellcomecollection.org/image/b30611751_0004.jp2/full/800%2C/0/default.jpg)
