Biosynthesis of Thermopsis Alkaloids from Carbon-14 Dioxide. Evidence for the Formation of the Pyridone Bases from Lupanine Via 5,6-Dehydrolupanine

Abstract

The observed relative rates and chronology of labelling of the alkaloids of Thermopsis rhombifolia and T. caroliniana following pulse feeding of 14CO2 were consistent with the formation of the pyridone bases from lupanine, via 5,6-dehydrolupanine. Rhombifoline appears to be the first of the tricyclic bases to be formed from the tetracyclic ones. No evidence was obtained for the formation of sparteine, casting doubt on its role in the formation of these alkaloids.