Non‐enzymatic synthesis of hygrine from acetoacetic acid and from acetonedicarboxylic acid

Hygrine, an intermediate in biosynthesis of tropane alkaloids, was formed non‐enzymatically by the coupling of γ‐methylaminobutyraldehyde with either acetoacetic acid or acetonedicarboxylic acid. When these ketoacids were fed to a tropane alkaloid‐free culture of tobacco roots, hygrine formation was observed. A possible process of this reaction is discussed.