Fig. 7. (a). Key NOESY correlations of the selected norditerpenoid alkaloids in depiction B1 (B1′). Depiction B1 shows the A-ring in chair conformation and depiction B1′ shows the A-ring in boat conformation. (b) Key NOESY correlations of the selected norditerpenoid alkaloids in depiction C2 (C2′). Depiction C2 shows the A-ring in chair conformation and depiction C2′ shows the A-ring in boat conformation. (c). Key NOESY correlations of the selected norditerpenoid alkaloids in depiction B4 (B4′). Depiction B4 shows the A-ring in chair conformation and depiction B4′ shows the A-ring in boat conformation.
