Co-Investigator(Kenkyū-buntansha) |
MURAI Akio Hokkaido University, Faculty of Science, Professor, 理学部, 教授 (20000838)
TOKOROYAMA Takashi Osaka City University, Faculty of Science, Professor, 理学部, 教授 (90046938)
SUGA Takayuki Hiroshima University, Faculty of Science, Professor, 理学部, 教授 (00033811)
GOTO Toshio Nagoya University, Faculty of Agriculture, Professor, 農学部, 教授 (20023369)
ISOE Sachihiko Osaka City University, Faculty of Science, Professor, 理学部, 教授 (90046946)
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Research Abstract |
(1) Various kinds of polyfunctional iridoids and seco-iridoids have been synthesized starting from natural (+)-genipin (Isoe). (2) Teleocidins, which are skin-irritant and tumor promoters, have been synthesized from an indole derivative by direct introduction of substituents on the indole nucleus (Goto). (3) In the biosynthesis of cyclic monoterpenoids, geranyl diphosphate bound to the active sites of the enzyme is transformed into the stereochemically specified allylic cation under the steric control characteristic to the enzyme in the respective plants (Suga). (4) Construction of the clerodane skeleton with 8,9-trans-di-methyl groups was investigated by way of cyclization of 2-(6'-silyl-4'-hexenyl)-3',4'- dimethyl-2-cyclohexenone with a bulky group (eg. silyl or alkoxycarbonyl group) at 2'-position (Tokoroyama). (5) A bourbonane type tricyclic system could be a possible biogenetic intermediate of Aphanamols, a novel perhydroazulene type sesquiterpenoid, from germacranoid precursor. Accor
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ding to this hypothesis, intramolecular [2+2]- photo-cycloaddition of an enol ester of a substituted cyclopentene acetic acid with 1-hydroxycyclopenten-3-one to a bourbonane skeleton was undertaken. Relative configuration and necessary functional groups of aphanamol A were furnished on this cycloaddition. After cleavage of the cyclobutane ring, the intermediate is to be transformed into the novel aphanamol skeleton (Hayashi). (6) Potato tuber tissues, when infected with Phytophthora infestans and arachidonic acid, generated hydrogen peroxide which then elicit accumulation of phytoalexins, respectively. The plant tissues, when inoculated with hydrogen peroxide, induced phytoalexin production, indicating that hydrogen peroxide is a primary substance for triggering the phytoalexin production in potato. These characteristics of hydrogen peroxide were also found with sweet potato, kidney bean, and sugar beet. Isolation of an endogenous elicitor, which increases in potato tissues in contact with hydrogen peroxide, was also attempted (Mural). Less
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