C₁₉-Diterpenoid Alkaloids from <i>Aconitum </i><i>h</i><i>emsleyanum</i> var. <i>c</i><i>ircinatum</i>

Seven new C19-diterpenoid alkaloids, circinasines A−G (1−7), together with six known compounds, talatisamine, yunaconitine, senbusine A, sachaconitine, hemsleyanisine, and isohemsleyanisine, were isolated from the roots of Aconitum hemsleyanum var. circinatum. The structures of 1−7 were determined by the interpretation of spectroscopic data and by the single-crystal X-ray crystallographic analysis of 6 and the acetonide derivative of 1. In addition, the structures of hemsleyanisine and isohemsleyanisine were revised from 8 and 9 to 10 and 11, respectively.