title: Synthesis and structures of regioisomeric hydnocarpin-type flavonolignans.
abstract: Flavonolignans represent natural compounds whose biosynthesis presumes a radical coupling of a ring B catecholic flavonoid with a molecule of coniferyl alcohol or an analogue. Many natural flavonolignans can exist as regioisomers, depending on how the coupled coniferyl alcohol moiety orients to the flavonoid. These regioisomers are often difficult to separate and have virtually identical NMR spectra. Structural assignments for some have changed with time or have been given without proof. We here report syntheses of both regioisomers of the flavonolignan hydnocarpin and one isomer of a plant isolate previously known as 5'-methoxyhydnocarpin. This isomer, here renamed 5'-methoxyhydnocarpin-D, was recently shown to be a potent inhibitor of a Staphylococcus aureus multidrug resistant efflux pump.
authors.affiliation: Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA.
authors.forename: N R
authors.initials: NR
authors.lastname: Guz
authors.forename: F R
authors.initials: FR
authors.lastname: Stermitz
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000138:chemical synthesis* / Q000737:chemistry; D005419:Flavonoids / Q000138:chemical synthesis* / Q000737:chemistry; D044947:Flavonolignans; D047311:Luteolin; D009682:Magnetic Resonance Spectroscopy; D010636:Phenols / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D012838:Silymarin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: C405502:5'-methoxyhydnocarpin; D000894:Anti-Inflammatory Agents, Non-Steroidal; D005419:Flavonoids; D044947:Flavonolignans; D010636:Phenols; D012838:Silymarin; C073621:hydnocarpin; C010559:coniferyl alcohol; D047311:Luteolin