Cactus alkaloids

Abstract

Twenty-four species of cacti have been surveyed for alkaloids using Meyer's test (KHgI) and gas chromatography to detect their presence. The following twenty-three species, not previously known to contain alkaloids, were found to contain alkaloids with a molecular weight greater than 125: Thelocactus bicolor, Neobessey sp., Echinocereus pectinatus, Neolloydia conoidea, Mammillaria melanocentra, Escobaria tuberculosa, Escobaria dasyacantha, Mammillaria zaccariniana, Ferocactus hamatocanthus, Mammillaria candida, Ferocactus latispinus, Mammillaria uncinate, Echinocactus palmeri, Ferocactus robustus, Mammillaria viperina, Coryphantha reduncuspina, Echinocactus histrix, Echinofossulocactus pectacanthus, Echinocereus enneucanthus, Mammillaria bucareiensis, Selenicereus grandifloras, Ferocactus wislizeni, and Echinocereus chloranthus. Opuntia schotti did not contain any alkaloids. The absolute configuration of the cactus alkaloid macromerine has been proved to be I by relating it to 1-adrenaline (II). The proof required that the alkaloid be synthesized optically active. [Diagrams] The structure of he cactus alkaloid gigantine (III) has been proven by degrading it to carnegine (IV) another known cactus alkaloid, and by the synthesis of d, 1-gigantine. The absolute configurating of gigantine was established when the degradation product, carnegine, proved to be optically active. The absolute configuration of 1-carnegine had been previously established.