نتایج جستجو برای: quaternary ammonium salts

تعداد نتایج: 63152  

Journal: :Beilstein Journal of Organic Chemistry 2008
Chuanfa Ni Fang Wang Jinbo Hu

BACKGROUND Although the nucleophilic difluoromethylation of aldehydes, ketones, and imines has been realized with PhSO(2)CF(2)H and related reagents, there are still no reports on the enantioselective nucleophilic reactions. RESULTS With a chiral quaternary ammonium salt as the catalyst and KOH as the base, we describe the first enantioselective difluoromethylation of aromatic aldehydes with ...

Journal: :Zeitschrift fur Naturforschung. C, Journal of biosciences 1998
H Kleszcyńska M Oświecimska S Witek S Przestalski

The antioxidant activity of five new compounds from a group of quaternary ammonium salts with antioxidant function has been investigated. The effect of the compounds on the degree of lipid oxidation in the erythrocyte membrane subjected to UV radiation was studied. It was found that all the salts used decreased oxidation of the lipids in the erythrocyte membrane. The antioxidant activity of the...

Journal: :Molecules 2015
Tiina Laaksonen Sami Heikkinen Kristiina Wähälä

Chiral tertiary and quaternary amine solvating agents for NMR spectroscopy were synthesized from the wood resin derivative (+)-dehydroabietylamine (2). The resolution of enantiomers of model compounds [Mosher's acid (3) and its n-Bu₄N salt (4)] (guests) by (+)-dehydroabietyl-N,N-dimethylmethanamine (5) and its ten different ammonium salts (hosts) was studied. The best results with 3 were obtain...

2004
Uwe Monkowius Stefan Nogai Hubert Schmidbaur

High-yield syntheses of the bromide (1a) and picrate salts (1b) of the 5-azonia-spiro[4]nonane cation [(CH2)4N(CH2)4] are reported. In the single crystal X-ray diffraction analyses of the two salts the spirocyclic quaternary ammonium cations have their five-membered rings in envelop and twist conformations modified by packing forces. The conformation found experimentally for 1a has C2-symmetry ...

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