51 2重,3重分子加水分解性タンニンの単離と構造

概要

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1) Two new dimeric hydrolysable tannins, gemins B (3) and C (4) have been isolated from the leaf extract of Geum japonicum, and their structures were elucidated by comparison of the ^1H-NMR (200 MHz) spectra with that of previously isolated gemin A (2). 2) Three novel dimeric hydrolysable tannins, rugosins D (5), E (6) and F (7) have been isolated from the flower of Rosa rugosa. Upon the partial hydrolysis with hot water, rugosins D〜F gave rugosins A (9), B (11) and C (12), respectively, in addition to tellimagrandin-I (10). Rugosins A〜C, new monomeric tannins, were also obtained from the flower of R. rugosa. Based on the structures of rugosins A〜C which were elucidated by the chemical and spectral evidences, rugosins D〜F were formulated as 5, 6 and 7. 3) An additional new tannin, rugosin G, was isolated from the flower of R. rugosa, and its structure 8, which is the first example of trimeric hydrolysable tannin, was elucidated. 4) The CD spectra of these tannins indicate that the empirical rules for determining the stereochemistry of the monomeric tannins by the signs and amplitudes of the Cotton effects about 230 and 280 nm, which were recently reported by the authors, can be applied to the oligomeric hydrolysable tannins.
天然有機化合物討論会の論文
1982-09-10