The Structures of Anhweidelphinine, Bulleyanitines A-C, Puberaconitine, and Puberaconitidine

The structures of the six norditerpenoid alkaloids listed in the title have been reported to contain a β-methoxyl group at C-1. However, the 13C-nmr spectral evidence for all these alkaloids and chemical correlation studies of puberaconitine and puberaconitidine clearly indicate a C-1 α-methoxyl group. In contrast to mass spectral evidence, 13C-nmr shift data can be reliably used as a diagnostic tool for the assignment of configuration of the oxygen function at C-1 in this family of alkaloids