Macrorhynines A and B, Two Novel Norditerpenoid Alkaloids from Aconitum macrorhynchum

Two novel norditerpenoid alkaloids, macrorhynines A and B ( 1 and 2 ), together with seven known compounds, were isolated from Aconitum macrorhynchum. The structures of the new compounds were elucidated as (1 α ,6 α ,14 α )‐8‐acetoxy‐1,6,16‐trimethoxy‐4‐(methoxymethyl)aconitan‐14‐yl 4‐methoxybenzoate ( 1 ) and (1 α ,6 α ,14 α )‐8‐acetoxy‐13‐hydroxy‐1,6,16‐trimethoxy‐4‐(methoxymethyl)aconitan‐14‐yl 4‐methoxybenzoate ( 2 ) on the basis of spectral analyses. The novel compounds were found to contain the rare C(19)N, azomethine, group.