96(PB3-7) 担子菌が生産する配糖体抗生物質の構造研究(ポスター発表の部)

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A strain of Basidiomycetes sp. produces glycosidic antibiotics, MA (tentative name), which exhibit inhibitory activity against gram-positive bacteria. The structures of DM-A (1a), B (1b), and C (1c) obtained by deacetylation of MA were elucidated by spectroscopic and chemical methods. DM-A, B, and C were isolated by HPLC as their peracetyl phenacyl esters (2a, 2b, 2c) and methanolysis of 2a, 2b, 2c gave two methyl D-xyloside, one methyl D-glucoside, and C_<26> long-chain aliphatic acid methyl esters (3a, 3b, 3c). The structure of sugar moiety was determined by ^1H-COSY, C-H COSY, and long-range C-H COSY analyses. The positions of four hydroxy groups in aglycone (3a, 3b, 3c) were elucidated by degradative reactions (Scheme 1) and the absolute configurations were established by the stereoselective synthesis of the degradation products (7a, 7b, 7c and 8a, 8b, 8c), exciton chirality method for 3c, and transformation of 3a, 3b, 3c to 15a, 15b, 15c. Permethylation of 2a, 2b, 2c, followed by methanolysis and oxidation of the aglycone parts (4a, 4b, 4c) revealed that the trisaccharide group is located at C-21 in 3a and C-22 in 3b and 3c. On the basis of the above data, the total structures of 1a, 1b, 1c were clalified as shown in Fig. 1.
天然有機化合物討論会の論文
1987-07-25