Mccrearamycins A-D, Geldanamycin-Derived Cyclopentenone Macrolactams from an Eastern Kentucky Abandoned Coal Mine Microbe

Four cyclopentenone‐containing ansamycin polyketides (mccrearamycins A–D), and six new geldanamycins (Gdms B–G, including new linear and mycothiol conjugates), were characterized as metabolites of Streptomyces sp. AD‐23‐14 isolated from the Rock Creek underground coal mine acid drainage site. Biomimetic chemical conversion studies using both simple synthetic models and Gdm D confirmed that the mccrearamycin cyclopentenone derives from benzilic acid rearrangement of 19‐hydroxy Gdm, and thereby provides a new synthetic derivatization strategy and implicates a potential unique biocatalyst in mccrearamycin cyclopentenone formation. In addition to standard Hsp90α binding and cell line cytotoxicity assays, this study also highlights the first assessment of Hsp90α modulators in a new axolotl embryo tail regeneration (ETR) assay as a potential new whole animal assay for Hsp90 modulator discovery

Comparison of thermal effects of stilbenoid analogs in lipid bilayers using differential scanning calorimetry and molecular dynamics: correlation of thermal effects and topographical position with antioxidant activity

In previous studies it was shown that cannabinoids (CBs) bearing a phenolic hydroxyl group modify the thermal properties of lipid bilayers more significantly than methylated congeners. These distinct differential properties were attributed to the fact that phenolic hydroxyl groups constitute an anchoring group in the vicinity of the headgroup, while the methylated analogs are embedded deeper towards the hydrophobic region of the lipid bilayers. In this work the thermal effects of synthetic polyphenolic stilbenoid analogs and their methylated congeners have been studied using differential scanning calorimetry (DSC).Molecular dynamics (MD) simulations have been performed to explain the DSC results. Thus, two of their phenolic hydroxyl groups orient in the lipid bilayers in such a way that they anchor in the region of the headgroup. In contrast, their methoxy congeners cannot anchor effectively and are embedded deeper in the hydrophobic segment of the lipid bilayers. The MD results explain the fact that hydroxystilbenoid analogs exert more significant effects on the pretransition than their methoxy congeners, especially at low concentrations. To maximize the polar interactions, the two phenolic hydroxyl groups are localized in the vicinity of the head-group region, directing the remaining hydroxy group in the hydrophobic region. This topographical position of stilbenoid analogs forms a mismatch that explains the significant broadening of the width of the phase transition and lowering of the main phasetransition temperature in the lipid bilayers. At high concentrations, hydroxy and nonhydroxy analogs appear to form different domains. The correlation of thermal effects with antioxidant activity is discusse

Examining the origin of selectivity in the reaction of racemic alcohols with chiral N-phosphoryl oxazolidinones

A range of known and novel N-phosphoryl oxazolidinones and imidazolidinones were prepared and screened in the kinetic resolution of a range of racemic magnesium chloroalkoxides. Models are proposed to account for the enantioselectivity achieved based on a combination of chiral relay effects, generation of transient stereochemistry and the structure of the intermediate magnesium alkoxide

A group contribution model for determining the vaporization enthalpy of organic compounds at the standard reference temperature of 298K

Article on a group contribution model for determining the vaporization enthalpy of organic compounds at the standard reference temperature of 298 K

C-13 Contact Solvent Shifts in Radical-Anion Solutions - Mechanism of Spin-Density Transfer to Solvent

Journal URL: http://www.rsc.org/Publishing/Journals/cc/index.as

Correlation of Thermochemical Data with Gas-Phase Ionization-Potentials

Journal URL: http://pubs.acs.org/journals/joceah/index.htm

Hydrocarbon-Soluble Organoalkali-Metal Reagents - Preparation of Aryl Derivatives

Journal URL: http://pubs.acs.org/organometallics