P-4 マメゾウムシ類フェロモンの大類-赤坂法による立体異性体比の決定と立体化学-生物活性相関(ポスター発表の部)

概要

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The azuki bean weevil, Callosobruchus chinensis L. and the cowpea weevil, C. maculatus, are serious cosmopolitan pests of stored products such as cowpea, azuki or other pulses. The structures of the copulation release pheromones were proposed to be as 1 and 2. However, it was impossible to determine the absolute configurations because of the scarcity of the materials and the incorporation of other acids. In order to determine the absolute configurations of the natural products, we re-isolated the natural pheromones and synthesized optically active 1 and 2 via Evans asymmetric alkylation as a key step. The natural products and the synthetic samples were converted into the corresponding Ohrui-Akasaka esters, that were subjected to the 2D-HPLC analyses. The natural products were confirmed to be stereochemically impure. The stereoisomer constitution of 1 was determined to be R: S=3.3: 1 and that of 2 was determined to be (2R,6S): (2S,6R): (2S,6S): (2R,6R)=43: 38: 18: trace. (R)-1 was reported to be almost a half as active as (S)-1. This means that the female C. chinensis L. produces the biologically weaker enantiomer as a major isomer. On the other hand, there was an inclination for the more contained isomer of 2 in the natural product, to be more active.
天然有機化合物討論会の論文
2007-08-24