title: Studies on zoospore attracting activity. II. Synthesis of isoflavones and their attracting activity to Aphanomyces euteiches zoospore.
abstract: Nineteen isoflavones were synthesized and their attracting activity to Aphanomyces euteiches zoospore were investigated. Isoflavones (1, 2, 4, 16 and 19) with an unsubstituted B ring were synthesized by the oxidation of corresponding 2'-hydroxychalcones with thallium (III) nitrate trihydrate in methanolic perchloric acid. A hydroxyl group at the C-5 position in isoflavones was necessary for strong attraction to A. euteiches zoospore. The introduction of an additional hydroxyl group at the C-7 or C-4' position strengthened the attracting activity. Moreover, the methylation of the C-7 hydroxyl group strengthened the attracting activity, but the methylation of the C-4' hydroxyl group slightly weakened it. The naturally occurring isoflavones (9 and 10), which were reported to possess estrogen activity, showed moderate attracting activity.
authors.affiliation: Faculty of Pharmaceutical Sciences, Higashi Nippon Gakuen University, Hokkaido, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sekizaki
authors.forename: R
authors.initials: R
authors.lastname: Yokosawa
authors.forename: C
authors.initials: C
authors.lastname: Chinen
authors.forename: H
authors.initials: H
authors.lastname: Adachi
authors.forename: Y
authors.initials: Y
authors.lastname: Yamane
mesh_terms: D002599:Chalcone / Q000737:chemistry*; D007529:Isoflavones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D008745:Methylation; D009868:Oomycetes / Q000187:drug effects* / Q000502:physiology; D010084:Oxidation-Reduction; D013172:Spores, Fungal / Q000187:drug effects / Q000502:physiology
chemical_list: D007529:Isoflavones; D002599:Chalcone