The minor alkaloids of ipecacuanha

Abstract

Ipecacuanha had been used for many years in medical practice before Rogers (1), in 1912, showed that emetine, one of the constituent alkaloids, was a specific agent against dysentery. This discovery, in relation to the toll which the diseases takes in tropical countries, intensified the efforts of chemists to deduce the structure of the alkaloid in the hope of synthesising it. This hope was not finally achieved until 1950.

The final stages in selecting the correct structure for emetine were aided by a consideration fo the possible biogenetic route to the alkaloid in the light of current theories of the biogenesis of alkaloids. In consequences of this, a detailed examination of the alkaloidal material present in the root was undertaken in the hope of isolating some compound which might be a biogenetic intermediate. The results of that investigation are described in this thesis. At the same time the opportunity was taken to study the chemistry of the minor alkaloids.

The work on the structural formula of emetine had shown the marked specificity of the alkaloid in the treatment of amoebic dysentery. There are four centres of asymmetry in the molecule and inversion of the configuration at the asymmetric centres had to be ascertained. In the latter part of the thesis the initial experiments in the elucidation of the stereochemistry of emetine are described.

These results and the subsequent elucidation of the stereochemistry and the stereospecific synthesis of emetine and emetamine have been reported by Dr. Battersby and his associates in a series of papers in the Journal of the Society of Chemistry and Industrial and the Journal of the Chemical Society (80)(56)(57).