title: Conformational evaluation and detailed 1H and 13C NMR assignments of eremophilanolides.
abstract: Extensive application of 1D and 2D NMR methodology, combined with molecular modeling, allowed the complete 1H and 13C NMR assignments of eremophilanolides from Senecio toluccanus. Comparison of the experimental 1H, 1H coupling constant values with those generated employing a generalized Karplus-type relationship, using dihedral angles extracted from MMX and DFT calculations, revealed that the epoxidized eremophilanolides 1 and 2 show conformational rigidity at room temperature, whereas molecules 3-6, containing an isolated double bond, are conformationally mobile.
authors.affiliation: Departamento de Química, Unidad Profesional Interdisciplinaria de Biotecnología, Instituto Politécnico Nacional, Av. Acueducto s/n, La Laguna Ticomán, México D.F., 07340 Mexico. eburgenio@acei.upibi.ipn.mx
authors.forename: Eleuterio
authors.initials: E
authors.lastname: Burgueño-Tapia
authors.forename: Luis R
authors.initials: LR
authors.lastname: Hernández
authors.forename: Adriana Y
authors.initials: AY
authors.lastname: Reséndiz-Villalobos
authors.forename: Pedro
authors.initials: P
authors.lastname: Joseph-Nathan
mesh_terms: D002247:Carbon Isotopes; D006859:Hydrogen; D007554:Isotopes; D008958:Models, Molecular; D008968:Molecular Conformation; D009281:Naphthalenes / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D018517:Plant Roots / Q000737:chemistry; D000081223:Polycyclic Sesquiterpenes; D012674:Senecio / Q000737:chemistry; D012717:Sesquiterpenes
chemical_list: D002247:Carbon Isotopes; D007554:Isotopes; D009281:Naphthalenes; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes; C018286:eremophilane compounds; D006859:Hydrogen