Arcutinine, a new alkaloid from Aconitum arcuatum

The structure of arcutinine isolated as a crystalline mixture with arcutine from the aerial part of Aconitum arcuatum was established using H-1 and C-13 NMR, IR, and mass spectra and comparison with arcutine. Arcutinine, like arcutine, contains a C-5-C-20 bond instead of the usual C-10-C-20 bond in the C-20-diterpenoid carbon skeleton.