Enantioselective radical addition reactions to the CN bond utilizing chiral quaternary ammonium salts of hypophosphorous acid in aqueous media

2006 ◽  
pp. 5045-5047 ◽  
Author(s):  
Dae Hyan Cho ◽  
Doo Ok Jang
Keyword(s):  
Quaternary Ammonium ◽  
Aqueous Media ◽  
Radical Addition ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Addition Reactions ◽  
Hypophosphorous Acid

Cinchona alkaloid-based chiral catalysts act as highly efficient multifunctional organocatalysts for the asymmetric conjugate addition of malonates to nitroolefins

2015 ◽  
Vol 13 (40) ◽  
pp. 10216-10225 ◽  
Author(s):  
Veeramanoharan Ashokkumar ◽  
Ayyanar Siva
Keyword(s):  
Michael Addition ◽  
Quaternary Ammonium ◽  
Conjugate Addition ◽  
Quaternary Ammonium Salts ◽  
Cinchona Alkaloid ◽  
Ammonium Salts ◽  
Addition Reactions ◽  
Chiral Catalysts ◽  
Reaction Conditions ◽  
Highly Efficient

New pentaerythritol tetrabromide based chiral quaternary ammonium salts have been prepared and used as organocatalysts for enantioselective Michael addition reactions between various nitroolefins and Michael donors under mild reaction conditions with very good chemical yields and ee's.

Highly enantioselective Michael addition reactions with new trimeric chiral phase transfer catalysts

2015 ◽  
Vol 39 (4) ◽  
pp. 3098-3104 ◽  
Author(s):  
Arockiam Jesin Beneto ◽  
Jayaraman Sivamani ◽  
Veeramanoharan Ashokkumar ◽  
Rajendiran Balasaravanan ◽  
Kumaraguru Duraimurugan ◽  
...  
Keyword(s):  
Michael Addition ◽  
Quaternary Ammonium ◽  
Phase Transfer ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Addition Reactions ◽  
Chiral Phase ◽  
Catalytic Activities ◽  
Phase Transfer Catalysts ◽  
Chiral Phase Transfer Catalysts

New types of mesitylene based tri-site containing asymmetric quaternary ammonium salts 9 (9a and 9b) were synthesized and their catalytic activities were studied using Michael addition reactions with various chalcones and diethylmalonate under mild basic conditions with very good yields and ee's.

scholarly journals Cu Nanoparticle-Loaded Nanovesicles with Antibiofilm Properties. Part I: Synthesis of New Hybrid Nanostructures

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1542 ◽  
Author(s):  
Lucia Sarcina ◽  
Pablo García-Manrique ◽  
Gemma Gutiérrez ◽  
Nicoletta Ditaranto ◽  
Nicola Cioffi ◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Antimicrobial Agents ◽  
Aqueous Media ◽  
Quaternary Ammonium Salts ◽  
Hybrid Nanostructures ◽  
Ammonium Salts ◽  
Biofilm Inhibition ◽  
Transmission Electron ◽  
The Stability ◽  
A Charge

Copper nanoparticles (CuNPs) stabilized by quaternary ammonium salts are well known as antimicrobial agents. The aim of this work was to study the feasibility of the inclusion of CuNPs in nanovesicular systems. Liposomes are nanovesicles (NVs) made with phospholipids and are traditionally used as delivery vehicles because phospholipids favor cellular uptake. Their capacity for hydrophilic/hydrophobic balance and carrier capacity could be advantageous to prepare novel hybrid nanostructures based on metal NPs (Me-NPs). In this work, NVs were loaded with CuNPs, which have been reported to have a biofilm inhibition effect. These hybrid materials could improve the effect of conventional antibacterial agents. CuNPs were electro-synthesized by the sacrificial anode electrolysis technique in organic media and characterized in terms of morphology through transmission electron microscopy (TEM). The NVs were prepared by the thin film hydration method in aqueous media, using phosphatidylcholine (PC) and cholesterol as a membrane stabilizer. The nanohybrid systems were purified to remove non-encapsulated NPs. The size distribution, morphology and stability of the NV systems were studied. Different quaternary ammonium salts in vesicular systems made of PC were tested as stabilizing surfactants for the synthesis and inclusion of CuNPs. The entrapment of charged metal NPs was demonstrated. NPs attached preferably to the membrane, probably due to the attraction of their hydrophobic shell to the phospholipid bilayers. The high affinity between benzyl-dimethyl-hexadecyl-ammonium chloride (BDHAC) and PC allowed us to obtain stable hybrid NVs c.a. 700 nm in diameter. The stability of liposomes increased with NP loading, suggesting a charge-stabilization effect in a novel antibiofilm nanohybrid material.

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