10 エポキシ構造を有するシャクガ科の性フェロモンに関する研究(口頭発表の部)

抄録

Monoepoxy derivatives of (Z,Z,Z)-3,6,9-triunsaturated hydrocarbons have been identified as sex pheromone components of female moths which distribute in foreign countries and belong to Geometridae, one of the biggest family in Lepidoptera. In order to obtain some information about pheromones of Japanese species, the C_<18>-C_<23> trienes were systematically synthesized from linolenic acid and converted into a mixture of three racemic monoepoxides, 3,4-, 6,7- and 9,10-epoxydienes. After separation by MPLC and structure determination by 2D NMR, each positional isomer was offered to random screening tests and specific male attraction of ca. 20 species was newly observed. Besides this finding, their GC-MS data were utilized to identify a pheromonal C_<19>-3,4-epoxydiene secreted by an adult female of the Japanese giant looper, Ascotis selenaria cretacea, a serious defoliator of tea gardens. Chiral HPLC is helpful not only to determine the absolute configuration of a natural pheromone but also to prepare optically pure enantiomers for a biological assay. Using Chiralpak AS and AD columns operated under a normal phase condition and a Chiralcel OJR column operated under a reversed phase condition, enantiomers of each epoxydienes were successfully resolved, and then stereochemistry of the separated enantiomers was determined by a modified Mosher's method after methanolysis of the epoxy ring. Analysis of the natural pheromone of A. s. cretacea showed that the female produced the racemic mixture, while the males interestingly attracted to the pure (3R,4S)-isomer more strongly than the racemic mixture. Furthermore, epoxidation in the pheromone gland of A. s. cretacea was examined in vivo. GC-MS analysis of the gland extracts treated with a deuterated C_<19>-triene and other unsaturated hydrocarbons revealed that a monooxygenase of the pheromone biosynthesis regiospecifically attacked only the (Z)-double bond at 3-position but substrate specificity of this enzyme was rather low.