The Biogenesis of Alkaloids: Xii. The Mode of Formation of the Tropine Base of Hyoscyamine

Ornithine-2-C14 was fed to mature Datura stramonium plants and radioactive hyoscyamine was isolated from the whole plant, while the hyoscine obtained from the plant was inactive. Systematic degradation of the radioactive alkaloid indicated that all the activity was present in the 1 or 5, or both, positions of the tropine half of the alkaloid indicating that ornithine is a precursor of the ring system in tropine, but not of scopine, the base present in hyoscine.