48 Colletotrichum nicotianaeの生産するcolletotrichin類の生合成

概要

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Colletotrichin(I) is a phytotoxic substance isolated from fungi, and the structure has been rigorously established by X-ray chrystallography. In the course of our continuous searching for the related substances, we isolated two new compounds, colletotrichin B(II) and C(III) from the culture filtrate of Colletotrichum nicotianae. These compounds consist of unique norditerpene and polysubstituted γ-pyrone. The biosynthesis of these compounds was studied employing carbon magnetic resonance. All of the carbon atom signals were assigned from the multiplicities and by comparison of I with II, III and IV which was obtained by treatment with H_2O_2 in NaOH solution. The cmr spectra showed that I, II and III were biosynthesized through the combination of acetate-mevalonate-terpene pathway with acetate-polyketide pathway. From the data of labelled II and III together with those of I, the mechanism involving cyclization of geranyl-geranyl pyrophosphate, followed by epoxidation of terminal isopentenyl double bond, cleavage of Baeyer-Villiger type reaction would account for the biosynthetic pathway of colletotrichins as shown in scheme 2.
天然有機化合物討論会の論文
1978-08-22