Institution: | aDepartamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria RS, Brazil bDepartamento de Biologia e Química, Universidade Regional do Noroeste do Estado do Rio Grande do Sul (UNIJUI), Ijuí RS, Brazil |
Abstract: | Waltherine-C (5), a novel 14-membered cyclopeptide alkaloid has been isolated, together with four known cyclopeptide alkaloids, waltherine-A (1) and -B (2), scutianine-B (3) and adouetine-Y' (4), from the bark of Waltheria douradinha (Sterculiaceae) from Rio Grande do Sul, Brazil. The structure and NMR assignments of this new alkaloid were determined by 1D and 2D NMR techniques. The stereochemistry of the ring amino acid residue and the N,N-dimethyl amino acid side-chain has been assigned by gas chromatography employing modified cyclodextrins as chiral stationary phases. |