The Mitragyna Alkaloids

Gailey, Robert M (1953) The Mitragyna Alkaloids. PhD thesis, University of Glasgow.

Abstract

Mitraphylline is isolated from the hark of Mitragyna rubrostipulaceae and is separated from beta-sitosterol, quinovic acid and nitrogenous bases comprising alkaloidal congeners. The molecular formula, C21H26O4N2, the presence of one methoxyl group - probably incorporated in a methoxycarbonyl group, and the absence of rnethyl-imino groups are confirmed; but the alleged presence of an olefinic linkage is refuted and, contrary to previous statements, it is found that the alkaloid may be induced to yield a mono-acetyl derivative. The ultra-violet and infra-red absorption spectra of mitraphylline are measured and are shown to be consistent with an oxindole structure. Distillation of mitraphylline from zinc dust in vacuo is found to yield degradation products of considerable significance. In particular, isoquinoline is isolated from the basic fraction while a neutral product, C10H9ON, is identified as either 3-ethylidene-or 3-vinyl-oxindole since it affords 3-ethyloxindole on hydrogenation. Mitraphylline may therefore be regarded as a derivative of N-(beta-3-oxindolylethyl)perhydroisoquin-oline, in which only the suspected methoxycarbonyl group and one unidentified oxygen atom remain to be located. Moreover, the neutral compound, C10H9ON, is now shown to he identical with the "methylcarbostyril" which Barger, Dyer and Sargent had obtained from the related alkaloid, rhynchophylline. In the light of these facts the evidence reviewed shows that in the Mitragyna bases an oxindole group of alkaloids co-exists with the beta-carboline type indicated by previous investigations. Synthetic work described includes the syntheses of 1:7-dimethyltryptophan and of 9-methyl-, 1;9-dimethyl-, 2:9-dimethyl- and 1:2:9-trimethyl-beta-carbolines. The apparatus used for the extraction of the bark and a device for the chromatography of colourless substances are described.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Organic chemistry
• Date of Award: 1953
• Depositing User: Enlighten Team
• Unique ID: glathesis:1953-79081
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 31 Mar 2020 09:09
• Last Modified: 31 Mar 2020 09:09
• URI: https://theses.gla.ac.uk/id/eprint/79081