title: Rare prenylated isoflavones from Tephrosia calophylla.
abstract: Chemical re-examination of the roots of T. calophylla led to the isolation of four isoflavones, namely 2',4',5-trihydroxy-6,7-(2",2"-dimethylchromene)-8-gamma,gamma-dimethylallylisoflavone (1a, auriculatin), 2',5-dihydroxy-6,7-(2",2"-dimethylchromene)-4'-gamma,gamma-dimethylallyloxyisoflavone (2a, isoauriculatin), 3',4',5-trihydroxy-6,7-(2",2"-dimethylchromene)-8-gamma,gamma-dimethylallylisoflavone (1b, auriculasin), and 3',5-dihydroxy-6,7-(2",2"-dimethylchromene)-4'-gamma,gamma-dimethylallyl-oxyisoflavone (2b, isoauriculasin). Auriculasin and isoauriculasin are reported for the first time with full NMR assignments. All metabolites were fully characterized by 1D and 2D NMR techniques including COSY, HSQC, HMBC experiments, mass spectra and in part on the basis of X-ray diffraction. Accurate 'invariom' refinements with aspherical scattering factors were carried out for 1a, 1b and 2a.
authors.forename: Seru
authors.initials: S
authors.lastname: Ganapaty
authors.forename: Vimal
authors.initials: V
authors.lastname: Nair
authors.forename: Devarakonda Rama
authors.initials: DR
authors.lastname: Devi
authors.forename: Steve Thomas
authors.initials: ST
authors.lastname: Pannakal
authors.forename: Hartmut
authors.initials: H
authors.lastname: Laatsch
authors.forename: Birger
authors.initials: B
authors.lastname: Dittrich
mesh_terms: D007529:Isoflavones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D031304:Tephrosia / Q000737:chemistry*
chemical_list: D007529:Isoflavones