1-Phenethylisoquinoline alkaloids. Part II. The structures of alkaloids from Colchicum cornigerum(Sweinf.) Tackh. et Drar

Abstract

The structures of eight alkaloids from Colchicum cornigerum have been determined by a combination of spectroscopic methods, X-ray analysis, and chemical modifications; all eight belong to the new class of substances derived from 1-phenethylisoquinoline. One alkaloid, autumnaline, is the first unmodified 1-phenethylisoquinoline to be found in nature. The remaining seven could, in principle, be biosynthesised from (+)-, or (–)-autumnaline by two alternative modes of phenol coupling. Alkaloid CC-10 is probably the biological precursor of alkaloids CC-20, CC-2 and CC-3b.