Structural reassignment of epierythratidine, an alkaloid from erythrinafusca, based on nmr studies and computational methods

• OLIMPO GARCÍA-BELTRÁN ^[1] ; JORGE SOTO-DELGADO ^[1] ; PATRICIO ITURRIAGA-VÁSQUEZ ^[1] ; CARLOS ARECHE ^[1] ; BRUCE K CASSELS ^[1]
  1. [1] Universidad de Chile

     Universidad de Chile

     Santiago, Chile

     
• Localización: Journal of the Chilean Chemical Society (Boletín de la Sociedad Chilena de Química), ISSN-e 0717-6309, ISSN 0366-1644, Vol. 57, Nº. 3, 2012, págs. 1323-1327
• Idioma: inglés
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• Resumen

  • 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.