UCH9, a New Antitumor Antibiotic Produced byStreptomyces. II. Structure Elucidation of UCH9 by Mass and NMR Spectroscopy.
作者:RITSUKO KATAHIRA、YOICHI UOSAKI、HARUMI OGAWA、YOSHINORI YAMASHITA、HIROFUMI NAKANO、MAYUMI YOSHIDA
DOI:10.7164/antibiotics.51.267
日期:——
The structure of UCH9, which is a novel antitumor agent, was determined by spectroscopic methods. UCH9 consists of an aglycone and five 2, 6-dideoxy sugars (three D-olivoses, one 4-O-methyl-D-olivose and one D-oliose). Four of the five sugars are sequentially connected through a β1→3 linkage (olivose-1→3-4-O-methyl-olivose-1→3-oliose-1→3-olivose). On the basis of the results of spectroscopic analysis, it was found that UCH9 belongs to the aureolic acid family of antibiotics. The structure of UCH9 is unique in that mono- and tetrasaccharide moieties, and a long hydrophobic side chain (sec-butyl group) are attached to the aglycone, while di- and trisaccharide moieties and a methyl or a hydrogen are attached in the case of the known aureolic acid analogs. It is known that aureolic acid analogs form a dimer in the presence of Mg2+. NMR, FAB-MS and atomic absorption analysis revealed that UCH9 isolated from Streptomyces also forms a dimer, containing one equivalent molar Mg2+
Two-step synthesis of C-glycosyl juglones from unprotected sugars: a novel approach to angucycline antibiotics
作者:Goh Matsuo、Shuichi Matsumura、Kazunobu Toshima
DOI:10.1039/cc9960002173
日期:——
The two-steps synthesis of C-glycosyl juglones, versatile synthetic intermediates for angucycline antibiotics, has been developed by the C-glycosidation of naphthalene-1,5-diol with an unprotected sugar and the subsequent regioselective photooxygenation of the resultant C-glycosyl naphthalenediol.
Alldiastereomers of the 2-deoxypentoses and the 2,6-dideoxyhexoses were synthesized from 2-phenyl-1,3-dioxan-5-one hydrate (1), by alkylation via the RAMP-hydrazone (2). Some of the diastereomers were synthesized in the racemic form via the dimethylhydrazone (28). The 2-deoxypentoses were synthesized by alkylation with allyl bromide, followed by stereoselective reduction, ozonolysis, and deprotection
Highly practical aryl C-glycosidations of unprotected 1-OMe and 1-OH sugars with phenol and naphthol derivatives were effectively realized using montmorillonite K-10 as an environmentally compatible solid acid in CHCl3 or H2O. (C) 1997 Elsevier Science Ltd.
Practical synthesis of 2,6-dideoxy-d-lyxo-hexose (“2-deoxy-d-fucose”) from d-galactose
作者:Cynthia M. Shafer、Tadeusz F. Molinski
DOI:10.1016/s0008-6215(98)00160-8
日期:1998.8
2,6-Dideoxy-D-lyxo-hexose was prepared efficiently fromD-galactose in eight steps (25% overall yield). The synthesis is amenable to multigram scale-up.