title: Semi-synthesis and NMR spectral assignments of flavonoid and chalcone derivatives.
abstract: Previous investigations of the aerial parts of the Australian plant Eremophila microtheca and Syzygium tierneyanum resulted in the isolation of the antimicrobial flavonoid jaceosidin (4) and 2',6'-dihydroxy-4'-methoxy-3',5'-dimethyl chalcone (7), respectively. In this current study, compounds 4 and 7 were derivatized by acetylation, pivaloylation, and methylation reactions. The final products, 5,7,4'-triacetoxy jaceosidin (10), 5,7,4'-tripivaloyloxy jaceosidin (11), 5,7,4'-trimethoxy jaceosidin (12), 2',6'-diacetoxy-4'-methoxy-3',5'-dimethyl chalcone (13), 2'-hydroxy-4'-methoxy-6'-pivaloyloxy-3',5'-dimethyl chalcone (14), and 2'-hydroxy-4',6'-dimethoxy-3',5'-dimethyl chalcone (15) were all fully characterized by NMR and MS. Derivatives 10 and 13 have been previously reported but were only partially characterized. This is the first reported synthesis of 11 and 14. The natural products and their derivatives were evaluated for their antibacterial and antifungal properties, and the natural product, jaceosidin (4) and the acetylated derivative, 5,7,4'-triacetoxy jaceosidin (10), showed modest antibacterial activity (32-128 µg/ml) against Staphylococcus aureus strains. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Eskitis Institute for Drug Discovery, Griffith University, Brisbane, 4111, QLD, Australia.
authors.forename: Rohitesh
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Eskitis Institute for Drug Discovery, Griffith University, Brisbane, 4111, QLD, Australia.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Institute for Molecular Bioscience, University of Queensland, St Lucia, 4072, QLD, Australia.
authors.forename: Alysha G
authors.initials: AG
authors.lastname: Elliott
authors.affiliation: Institute for Molecular Bioscience, University of Queensland, St Lucia, 4072, QLD, Australia.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Kavanagh
authors.affiliation: Institute for Molecular Bioscience, University of Queensland, St Lucia, 4072, QLD, Australia.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Cooper
authors.affiliation: Eskitis Institute for Drug Discovery, Griffith University, Brisbane, 4111, QLD, Australia. r.davis@griffith.edu.au.
authors.forename: Rohan A
authors.initials: RA
authors.lastname: Davis
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D047188:Chalcones / Q000138:chemical synthesis* / Q000737:chemistry* / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D005419:Flavonoids / Q000138:chemical synthesis* / Q000737:chemistry* / Q000494:pharmacology; D005658:Fungi / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D013211:Staphylococcus aureus / Q000187:drug effects; D013329:Structure-Activity Relationship; D027842:Syzygium / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D047188:Chalcones; D005419:Flavonoids; C477508:jaceosidin
keywords: 13C; 1H; 2′,6′-dihydroxy-4′-methoxy-3′,5′-dimethyl chalcone; Eremophila microtheca; NMR; Syzygium tierneyanum; antimicrobial; chalcone; flavonoid; jaceosidin