著者

古森 徹哉 瀬戸口 信郎 川崎 敏男

出版者

天然有機化合物討論会実行委員会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

vol.10, pp.216-223, 1966

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The unknown, nonsteroidal, nonglycosidal and N-free substance, which had been obtained as crystals from the root tubers of Dioscorea bulbifera L. forma spontanea Makino et Nemoto, was found to be a mixture of at least three compounds. One of them, named bulbiferin C, m.p.255°, (α)_D +17.3°, was isolated only in trace and the structures of major component, bulbiferin B, m.p. 285°, (α)_D+103.0° and minor, bulbiferin A, m.p. 283°, (α)_D +16.2°, were investigated. Bulbiferin B, C_<19>H_<20>O_6, m.w. 344 (mass) has γ-lactone, β-substituted furane and no hydroxyl groups (positive Ehrlich reaction, I.R., U.V. and mass spectra). B is converted to A by hydrolysis with NaOH in pyridine followed by neutralisation and methylation with diazometane. Bulbiferin A,C_<20>H_<24>O_7, m.w. 376 (mass), has hydroxyl, ester, γ-lactone and β-substituted furane functions (Ehrlich reaction, I.R., U.V. and mass spectra). On treatment with NaBH_4 B is unchanged but by catalytic hydrogenation over PtO_2 it gives a hexahydro-compound having tertiary hydroxyl group indicating B (and also A) has an ether oxygen. The hydrogenated B is reduced with LiAlH_4 and the product is subjected to the Se-dehydrogenation to give 1,2,5-trimethyl naphthalene. The N.M.R. spectra of tetrahydro-B and -A indicate the presence of one tertiary methyl group. From these and other experimental data B and A are respectively assigned the partial formulae (a) and (b) of furano-norditerpene type. The results of a further investigation on the location of the functional groups which lead to the tentative structures of B and A are presented.