نتایج جستجو برای: nitrones
تعداد نتایج: 453 فیلتر نتایج به سال:
Some new metal(II) dichloride complexes with the ligands substituted nitrones of the general formula [ML2Cl2], where M= Co(II), Ni(II), Cu(II), Zn(II) and Cd(II), L=OCH=CHCH=C-CH=N(O)C6H4X (X=H,p-CH3,CH3O,CH3CO,F,Cl,and Br) have been prepared and characterized by elemental analysis, IR,H,C NMR and Vis/Uv spectroscopy. The IR spectral data showed that the nitrone ligands coordinated with the met...
A stereodivergent synthesis of enantiopure 3,6-dihydro-2H-pyrans is presented. The addition of lithiated enol ethers to carbohydrate-derived nitrones afforded syn- or anti-configured hydroxylamine derivatives 4a-d that were cyclized under Lewis acidic conditions to yield functionalized dihydropyrans cis- or trans-5a-d containing an enol ether moiety. This functional group was employed for a var...
We report the syntheses of antifungals containing the novel pharmacophores: oxaziridines, sulfonyloxaziridines, nitrones and nitronyl nitroxides. We hypothesized that multiple copies of the pharmacophore per molecule might be a prerequisite to enhance efficacy against the opportunistic pathogen, Pneumocystis carinii. Therefore structural optimization of the leads was based on this new “multival...
Isosorbide was esterified with acryloyl chloride and crotonic acid yielding isosorbide diacrylate (9a) and isosorbide dicrotonate (9b), which were reacted with benzaldehyde oxime in the presence of zinc(II) iodide and boron triflouride etherate as catalysts to obtain N-alkylated dinitrones 10a/b. Poly(isosorbide itaconite -co- succinate) 13 as a bio-based unsaturated polyester was cross-linked ...
Herein, twoN-substituted coumaryl hydroxylamines (compounds 1a and 1b) with long aliphatic chains were prepared in 8 steps with a novel synthetic protocol. They served as derivatization agents for aldehydes by the formation of nitrones under mild conditions, which can be readily analysed by LC-MS with good chromatographic performance, excellent fluorescent response, and high ionization strength...
The spontaneous addition of air oxygen to a dienolic compound, yielding a cyclic peroxide, was followed by spin trapping (ST) combined with EPR spectroscopy and mass spectrometry (MS). Using two different nitrones, the ST/EPR study allowed the detection of the spin adduct of a radical intermediate, and the radical centre in the addend was identified after similar experiments performed with two ...
The cyclization of a ribose-derived pentenose oxime with various halogen electrophiles showed bromine to be the most effective reagent, leading to 80% of L-lyxo/D-ribo-pyrroline N-oxides in an 84:16 diastereomeric ratio. In order to explore the scope of this facile process, several other γ ,δ unsaturated oximes were submitted to this reaction. Depending on the substitution pattern, 23 – 87%, yi...
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