title: Revision of the structure of escholidine.
abstract: The structure of the quaternary tetrahydroprotoberberine alkaloid escholidine is revised on the basis of 2D NMR spectroscopy and X-ray diffraction. In contrast to the originally reported constitution, escholidine bears an -OH group at C-9 and an -OCH3 group at C-10. The 1H and 13C NMR data and long-range 1H-13C and NOE interactions of escholidine are compared with those of thalifendine and tetrahydroberberrubine. The 15N NMR data of escholidine obtained by using long-range 1H-15N correlation experiments at natural abundance are also reported.
authors.affiliation: Department of Natural Drugs, Pharmaceutical Faculty, University of Veterinary and Pharmaceutical Sciences, Palackého 1-3, CZ-612 42 Brno, Czech Republic.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Chudík
authors.forename: Radek
authors.initials: R
authors.lastname: Marek
authors.forename: Pavlína
authors.initials: P
authors.lastname: Seckárová
authors.forename: Marek
authors.initials: M
authors.lastname: Necas
authors.forename: Jirí
authors.initials: J
authors.lastname: Dostál
authors.forename: Jirí
authors.initials: J
authors.lastname: Slavík
mesh_terms: D001600:Berberine Alkaloids / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004149:Dioxoles / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular
chemical_list: D001600:Berberine Alkaloids; D004149:Dioxoles; C510124:escholtzine