نتایج جستجو برای: βunsaturated ketones moieties
تعداد نتایج: 19705 فیلتر نتایج به سال:
We have prepared and structurally characterized a new class of Fe(II) PNP pincer hydride complexes [Fe(PNP-iPr)(H)(CO)(L)] n (L = Br-, CH3CN, pyridine, PMe3, SCN-, CO, BH4-; n = 0, +1) based on the 2,6-diaminopyridine scaffold where the PiPr2 moieties of the PNP ligand are connected to the pyridine ring via NH and/or NMe spacers. Complexes [Fe(PNP-iPr)(H)(CO)(L)] n with labile ligands (L = Br-,...
a series of hydroxysemicarbazone derivatives of substituted diaryl ketones and acetophenones were synthesized and their structures were confirmed by analytical and spectroscopic methods including elemental analysis, infrared and nuclear magnetic resonance spectroscopy. the derivatives were prepared by a condensation reaction between n-hydroxysemicarbazide and substituted diaryl ketones or aceto...
A novel tandem-biocatalysts system consisting of a monooxygenase-containing microorganism and an alcohol dehydrogenase is developed for the concurrent oxidations of methylene groups to ketones in one pot, providing green, clean and simple access to valuable ketones with high yield, excellent selectivity and efficient cofactor recycling.
The ubiquitous ketone carbonyl group generally deactivates substrates toward radical-based fluorinations, especially sites closest to it. Herein, ketones are used instead to direct aliphatic fluorination using Selectfluor, catalytic benzil, and visible light. Selective β- and γ-fluorination are demonstrated on rigid mono-, di-, tri-, and tetracyclic (steroidal) substrates employing both cyclic ...
Reductive aminases (RedAms) have recently emerged as promising biocatalysts for the synthesis of chiral secondary amines by coupling primary with aldehydes/ketones. However, access to tertiary remains more problematic, particularly when ketones amines. Here we show that scope these enzymes can be extended allow selective reductive aminations cyclic amines, such piperidines and morpholines, both...
Transfer hydrogenation processes catalyzed by manganese organometallic complexes are comprehensively reviewed. The reaction scope includes the reduction of aldehydes, ketones, imines, polyaromatic nitrogen heterocycles, esters, nitriles, and semihydrogenation internal alkynes. Special attention is devoted to ligand design for Mn-catalyzed asymmetric transfer prochiral ketones leading enantiomer...
This study has used proton transfer reaction-mass spectrometry (PTR-MS) for direct air analyses of volatile products resulting from the reactions of ozone with human skin lipids. An initial series of small-scale in vitro and in vivo experiments were followed by experiments conducted with human subjects in a simulated office. The latter were conducted using realistic ozone mixing ratios (approxi...
BACKGROUND The plant pathogenic fungus (such as Gibberella zeae, Fusarium oxysporum and Cytospora mandshurica) causes devastating disease in agriculture. The pathogenic fungus is responsible for billions of dollars in economic losses worldwide each year. In order to discover new fungicidal molecule with good fungicidal activity against G. zeae, F. oxysporum, and C. mandshurica, we sought to com...
Synthesis, Structure, and Properties of Homoleptic l-Oxa-l,3-diene Molybdenum and Tungsten Complexes
Z. Naturforsch. 50b, 315-325 (1995); received September 7, 1994 Oxadiene Complex, Molybdenum, Tungsten, X-Ray, Selective Hydrogenation Homoleptic tris(l-oxa-l,3-diene)molybdenum and tungsten complexes are formed as yel low, crystalline compounds in 54-80% isolated yield on treatment of the corresponding /3-unsubstituted a,/3-unsaturated ketones with W(CO)3(CH3CH2CN)3 or (y6-C6H6)Mo(CO)3 in ref...
Two organic deposits accumulated in a Kraft pulp mill during pulping of Eucalyptus globulus wood and throughout a TCF (totally chlorine free) bleaching sequence were characterized. One deposit was collected after cooking and an oxygen delignification stage while the other was collected after bleaching with hydrogen peroxide. The deposits were Soxhlet extracted with acetone, and the extracts red...
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