54889-72-4Relevant articles and documents
Production of novel bispyrone metabolites in the cellular slime mold Dictyostelium giganteum induced by zinc(II) ion
Nguyen, Van Hai,Kikuchi, Haruhisa,Sasaki, Hiraku,Iizumi, Kyoichi,Kubohara, Yuzuru,Oshima, Yoshiteru
, p. 583 - 588 (2017)
In this study, Zn2+induced the production of two new bispyrone-type metabolites, dictyobispyrone B and E, in the cellular slime mold Dictyostelium giganteum. Their structures were proposed on the basis of spectroscopic analysis and confirmed by chemical synthesis. They possess a novel α,α-bispyrone skeleton modified with long carbon chains. Both could be formed from two different polyketide chains through a novel biosynthetic pathway. Our results indicate that cultivation of cellular slime molds in the presence of Zn2+is a useful technique for discovering other structurally unique compounds.
Chemical synthesis of a glycolipid library by a solid-phase strategy allows elucidation of the structural specificity of immunostimulation by rhamnolipids
Bauer, Joerg,Brandenburg, Klaus,Zaehringer, Ulrich,Rademann, Joerg
, p. 7116 - 7124 (2007/10/03)
The first synthesis of a glycolipid library by hydrophobically assisted switching phase (HASP) synthesis is described. HASP synthesis enables flexible switching between solution-phase steps and solid-supported reactions conducted with molecules attached to a hydrophobic silica support. A library of glycolipids derived from the lead compound 1 - a strongly immunostimulatory rhamnolipid - with variations in the carbohydrate part, the lipid components, and the stereochemistry of the 3-hydroxy fatty acids was designed and synthesized. The enantiose lective synthesis of the 3-hydroxy fatty acid building blocks was achieved by employing asymmetric hydrogenation of 3-oxo fatty acids. Glycolipids were prepared by this approach without any intermediary isolation steps, mostly in excellent yields. Final deprotection to the carboxylic acids was accomplished by enzymatic ester cleavage. All prepared rhamnolipids were tested for their immunostimulatory properties against human monocyte cells by assaying the secretion of the cytokine tumor necrosis factor α (TNFα) into the medium. The observed structure-activity relationships of rhamnolipids indicate a specific, recognition-based mode of action, with small structural variations in the rhamnolipids resulting in strong effects on the immunostimulatory activities of the rhamnolipids at low micromolar concentrations.
Asymmetric total synthesis of (-)-deoxoprosophylline
Jourdant, Angélique,Zhu, Jieping
, p. 3431 - 3434 (2007/10/03)
Asymmetric syntheses of (-)-deoxoprosophylline from chiral L-N,N-dibenzyl serine (TBDMS) aldehyde is reported. A highly diastereoselective intramolecular reductive amination of ω-oxo amino diol is a key step of the present synthesis.