A minor arcutine-type C20-diterpenoid alkaloid iminium constituent of “fu zi”

A rare arcutine-type C20-diterpenoid alkaloid was characterized as a minor constituent of “fu zi” (the lateral roots of Aconitum carmichaelii). The C20-diterpenoid alkaloid is an iminium named aconicarmicharcutinium A and obtained as hydroxide (1) and trifluoroacetate (1a) forms. Structures of 1 and 1a were elucidated by comprehensive analysis of spectroscopic data including 19F and 2D NMR experiments. Compounds 1 and 1a represent the first examples of the arcutine-type C20-diterpenoid alkaloid iminium.