Expedient and Practical Synthesis of CERT-Dependent Ceramide Trafficking Inhibitor HPA-12 and Its Analogues

International audienc

Méditation et bien-être, qu’en disent les élèves ?

International audienc

Preparation and Spectroscopic, Magnetic, and Electrochemical Studies of Mono-/Biradical TEMPO Derivatives

A comparison set of mono-/biradical TEMPO derivatives was prepared, novel compounds were fully characterized, and their physicochemical properties were determined. Cyclic voltammetry revealed reversible redox behavior for all studied nitroxides. Moreover, the electron-withdrawing substituents increased the oxidation potential of the respective nitroxides in comparison to electron-donating groups. While EPR spectra of monoradicals in dichloromethane at 295 K reveal the expected three-line signal, spectra of biradicals show more complex features. DFT and MP2 calculations indicate that the EPR splitting pattern of dinitroxide <b>7</b> could be explained by its interactions with solvent molecules. In the solid state, mononitroxides <b>4</b> and <b>5</b> behave as a Heisenberg antiferromagnetic chain, whereas dinitroxides <b>6</b>–<b>8</b> are almost isolated paramagnetic diradicals coupled in an antiferromagnetic manner

Preparation and Spectroscopic, Magnetic, and Electrochemical Studies of Mono-/Biradical TEMPO Derivatives

A comparison set of mono-/biradical TEMPO derivatives was prepared, novel compounds were fully characterized, and their physicochemical properties were determined. Cyclic voltammetry revealed reversible redox behavior for all studied nitroxides. Moreover, the electron-withdrawing substituents increased the oxidation potential of the respective nitroxides in comparison to electron-donating groups. While EPR spectra of monoradicals in dichloromethane at 295 K reveal the expected three-line signal, spectra of biradicals show more complex features. DFT and MP2 calculations indicate that the EPR splitting pattern of dinitroxide <b>7</b> could be explained by its interactions with solvent molecules. In the solid state, mononitroxides <b>4</b> and <b>5</b> behave as a Heisenberg antiferromagnetic chain, whereas dinitroxides <b>6</b>–<b>8</b> are almost isolated paramagnetic diradicals coupled in an antiferromagnetic manner

Preparation and Spectroscopic, Magnetic, and Electrochemical Studies of Mono-/Biradical TEMPO Derivatives

A comparison set of mono-/biradical TEMPO derivatives was prepared, novel compounds were fully characterized, and their physicochemical properties were determined. Cyclic voltammetry revealed reversible redox behavior for all studied nitroxides. Moreover, the electron-withdrawing substituents increased the oxidation potential of the respective nitroxides in comparison to electron-donating groups. While EPR spectra of monoradicals in dichloromethane at 295 K reveal the expected three-line signal, spectra of biradicals show more complex features. DFT and MP2 calculations indicate that the EPR splitting pattern of dinitroxide <b>7</b> could be explained by its interactions with solvent molecules. In the solid state, mononitroxides <b>4</b> and <b>5</b> behave as a Heisenberg antiferromagnetic chain, whereas dinitroxides <b>6</b>–<b>8</b> are almost isolated paramagnetic diradicals coupled in an antiferromagnetic manner

Preparation and Spectroscopic, Magnetic, and Electrochemical Studies of Mono-/Biradical TEMPO Derivatives

A comparison set of mono-/biradical TEMPO derivatives was prepared, novel compounds were fully characterized, and their physicochemical properties were determined. Cyclic voltammetry revealed reversible redox behavior for all studied nitroxides. Moreover, the electron-withdrawing substituents increased the oxidation potential of the respective nitroxides in comparison to electron-donating groups. While EPR spectra of monoradicals in dichloromethane at 295 K reveal the expected three-line signal, spectra of biradicals show more complex features. DFT and MP2 calculations indicate that the EPR splitting pattern of dinitroxide <b>7</b> could be explained by its interactions with solvent molecules. In the solid state, mononitroxides <b>4</b> and <b>5</b> behave as a Heisenberg antiferromagnetic chain, whereas dinitroxides <b>6</b>–<b>8</b> are almost isolated paramagnetic diradicals coupled in an antiferromagnetic manner

Conformational, Spectroscopic, and Molecular Dynamics DFT Study of Precursors for New Potential Antibacterial Fluoroquinolone Drugs

Biological activity, functionality, and synthesis of (fluoro)­quinolones is closely related to their precursors (for instance 3-fluoroanilinoethylene derivatives) (i.e., their functional groups, conformational behavior, and/or electronic structure). Herein, the theoretical study of 3-fluoroanilinoethylene derivatives is presented. Impact of substituents (acetyl, methyl ester, and ethyl ester) on the conformational analysis and the spectral behavior is investigated. The B3LYP/6-311++G** computational protocol is utilized. It is found that the intramolecular hydrogen bond N–H···O is responsible for the energetic preference of <i>anti</i> (a) conformer (<i>anti</i> position of 3-fluoroanilino group with respect to the CC double bond). The Boltzmann ratios of the conformers are related to the differences of the particular dipole moments and/or their dependence on the solvent polarity. The studied acetyl, ethyl ester, and methyl ester substituted fluoroquinolone precursors prefer in the solvent either EZa, ZZa, or both conformers equally, respectively. In order to understand the degree of freedom of rotation of the <i>trans</i> ethyl ester group, B3LYP/6-311G** molecular dynamic simulations were carried out. Vibrational frequencies, electron transitions, as well as NMR spectra are analyzed with respect to conformational analysis, including the effect of the substituent. X-ray structures of the precursors are presented and compared with the results of the conformational analysis