118(P60) シガトキシン絶対配置決定と抗体調製への合成化学的アプローチ(ポスター発表の部)

概要

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Ciguatoxin (CTX, 1) is a principal toxin causing ciguatera, one of the largest poisoning caused by natural toxins. Annual ciguatera patients are estimated to be over twenty thousand. In 1989, Yasumoto established the whole structure of 1 and its congner, Ciguatoxin 4B, except the absolute configuration and the C2 stereochemistry. Extremely low accessibility of this toxin hampers further studies on the absolute configuration, pharmacological studies at the molecular level and development of immunoassay system for differentiating poisonous fishes. Therefore, synthetic studies aimed for solving these problems are of great interest. We have first determined the absolute configuration of C2 stereogenic center of 1 by chemical means. The C11-p-bromobenzoate (14) of the AB ring model compound of CTX4A showed a strong exciton chirality CD spectrum due to interaction between the C11-p-bromobenzoate and the C5-butadienyl group. This distinct interaction is very useful for determination of the C5 configuration, and very recently Yasumoto and Satake succeeded in preparation of p-bromobenzoate of CTX4A and determination of the absolute configuration of CTX4A. Furthermore, the ABC ring fragment (15) was designed and synthesized as a haptenic compound, which was then conjugated with proteins and subjected to immunization to prepare the specific anti-ciguatoxin antibody.
1996-09-02