Resumen de Structural reassignment of epierythratidine, an alkaloid from erythrinafusca, based on nmr studies and computational methods
Olimpo García-beltrán, Jorge Soto-delgado, Patricio Iturriaga-vásquez, Carlos Areche, Bruce K Cassels
The diene Erythrina alkaloids erysotrine (1), erysodine (2), erythraline (3), erytharbine (4), and erysotrine N-oxide (5), plus the hydroxylated dihydro derivative of 1, epierythratidine (6) were isolated from seeds of Erythrina fusca Lour., and their ¹H and 13C NMR spectra were completely assigned using 2D experiments (H-H COSY, HMQC, HMBC and H-H NOESY). Our assignments for 1-5 agree well with the literature, but the present work shows that the published interpretation of the spectra of 6 must be revised. A combined study based on NMR data and quantum-mechanical calculations using DFT/GIAO indicate that 6 is the correct structure of epierythratidine.
