title: Syntheses and biological activities of dihydro-5,6-dehydrokawain derivatives.
abstract: The syntheses and biological activities of dihydro-5,6-dehydrokawain derivatives against plant pathogenic fungi and termites were investigated. Dihydro-5,6-dehydrokawain was isolated by a simple method without chromatography from the leaves of Alpinia speciosa K. SCHUM. The white crystalline compound obtained was identified as dihydro-5,6-dehydrokawain (1) by instrumental analyses. 4-Hydroxy-6-(2-phenylethyl)-2H-pyran-2-one (3) was prepared by hydrolyzing dihydro-5,6-dehydrokawain. Three dihydro-5,6-dehydrokawain derivatives were synthesized by reacting 3 with phosphoric agents. Among the synthesized compounds, dimethyl [6-(2-phenylethyl)-2-oxo-2H-pyran-4-yl]phosphorothionate (4) had the strongest antifungal activity of 91% at 100 ppm against Corticium rolfsii.
authors.affiliation: Department of Bioscience and Biotechnology, College of Agriculture, University of the Ryukyus, Okinawa, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tawata
authors.forename: S
authors.initials: S
authors.lastname: Taira
authors.forename: N
authors.initials: N
authors.lastname: Kobamoto
authors.forename: M
authors.initials: M
authors.lastname: Ishihara
authors.forename: S
authors.initials: S
authors.lastname: Toyama
mesh_terms: D000818:Animals; D000935:Antifungal Agents / Q000138:chemical synthesis* / Q000494:pharmacology; D007313:Insecta; D007306:Insecticides / Q000138:chemical synthesis*; D015394:Molecular Structure; D010946:Plants, Medicinal / Q000737:chemistry*; D011753:Pyrones / Q000138:chemical synthesis* / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: D000935:Antifungal Agents; D007306:Insecticides; D011753:Pyrones; C052296:7,8-dihydro-5,6-dehydrokawain