Biosynthesis of the lythraceae alkaloids: incorporation of lysine

Radioactivity from [2-14C]- and from [6-14C]-lysine enters the Lythraceae alkaloids decodine (1) and decinine (2); partial degradation of the alkaloids shows that incorporation is non-random and indicates that the C5N moiety which constitutes ring A of the alkaloids is derived from lysine which is incorporated by way of a symmetrical intermediate.