Construction of chiral quaternary carbon center via catalytic asymmetric aza-Henry reaction with α-substituted nitroacetates

RSC Advances ◽  
2014 ◽  
Vol 4 (39) ◽  
pp. 20346-20350 ◽  
Author(s):  
Minghua Li ◽  
Nan Ji ◽  
Ting Lan ◽  
Wei He ◽  
Rui Liu
Keyword(s):  
Quaternary Ammonium ◽  
Mixed Solvents ◽  
Acid Ethyl Ester ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Quaternary Carbon ◽  
Henry Reaction ◽  
Mild Conditions ◽  
Nitropropionic Acid ◽  
High Yields

The catalytic enantioselective aza-Henry reaction of N-Boc aldimines 2 and 2-nitropropionic acid ethyl ester 3 in mixed solvents were catalyzed by cinchona quaternary ammonium salts to form a new quaternary carbon center. High yields (up to 90%), excellent enantioselectivities (up to 99% ee) and diastereoselectivities ratio (up to 22 : 1) were successfully obtained with mild conditions.

Palladium-Catalysed Cross-Coupling of Benzylammonium Salts with Boronic Acids under Mild Conditions

Synthesis ◽  
2017 ◽  
Vol 50 (04) ◽  
pp. 793-802 ◽  
Author(s):  
Robert Phipps ◽  
Paul Türtscher ◽  
Holly Davis
Keyword(s):  
Quaternary Ammonium ◽  
Good Yield ◽  
Oxidative Addition ◽  
Cross Coupling ◽  
Boronic Acids ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Full Account ◽  
Mild Conditions

Herein, we give a full account of the development of the palladium­-catalysed cross-coupling of benzylammonium salts with boronic acids. A range of benzylamine-derived quaternary ammonium salts can be coupled with boronic acids under relatively mild conditions. Our optimization has identified ligands that can be used to chemoselectively cross-couple at the ammonium in the presence of chlorides. We demonstrate that intramolecular palladium-catalysed C–H activation is also a viable pathway for the putative benzyl-Pd(II) intermediate obtained upon oxidative addition and have optimised this to obtain fluorene in good yield.

scholarly journals Synthesis and characterization of bio-based quaternary ammonium salts with gibberellate or l-tryptophanate anion

2020 ◽  
Vol 151 (9) ◽  
pp. 1365-1373
Author(s):  
Daria Szymaniak ◽  
Juliusz Pernak ◽  
Tomasz Rzemieniecki ◽  
Damian Krystian Kaczmarek ◽  
Roman Andrzejak ◽  
...  
Keyword(s):  
Biological Activity ◽  
Plant Growth ◽  
Gibberellic Acid ◽  
Quaternary Ammonium ◽  
Quaternary Ammonium Salts ◽  
Biologically Active ◽  
Ammonium Salts ◽  
Ionic Form ◽  
Natural Substances ◽  
High Yields

Abstract Numerous biologically active acids can be transformed into an ionic form in a facile way and combined with appropriate quaternary ammonium cation to improve their application properties or biological activity. This study describes the synthesis of new quaternary ammonium salts with anions of gibberellic acid, a common plant growth regulator from the gibberellin group, or l-tryptophan, an important precursor of auxin biosynthesis. The surface-active tetrapentylammonium ion and natural substances such as acetylcholine, choline, and quinine were the sources of cations. Novel salts of gibberellic acid and l-tryptophan were obtained with high yields exceeding 97% as a result of the metathesis reaction or the neutralization of quaternary ammonium hydroxides. Phase transition temperatures, thermal and chemical stability, and solubility in solvents with different polarities were determined for all obtained salts. On the basis of studies regarding the influence of synthesized salts on the post-harvest longevity and quality of leaves of Convallaria majalis, it was established that the biological activity of the natural plant regulators in most cases was maintained. Therefore, it can be concluded that the conversion of the active substance into the form of a quaternary ammonium salt results in obtaining novel forms of plant growth regulators with favourable physicochemical properties while maintaining the efficacy of the biological active ingredients. Graphic abstract

Synthesis and stability of 1-aminoalkylphosphonic acid quaternary ammonium salts

2021 ◽  
Author(s):  
Tomasz K. Olszewski ◽  
Anna Brol
Keyword(s):  
Phosphonic Acid ◽  
Quaternary Ammonium ◽  
Alkylating Agent ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Aminoalkylphosphonic Acid

An effective protocol for quaternization of simple 1-aminoalkylphosphonic acids under basic conditions and using Me2SO4 as convenient alkylating agent is reported. In the course of reaction phosphonic acid quaternary ammonium...

scholarly journals Green Accelerated Synthesis, Antimicrobial Activity and Seed Germination Test of Quaternary Ammonium Salts of 1,2-bis(4-pyridyl)ethane

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2424 ◽  
Author(s):  
Tăbăcaru ◽  
Botezatu ◽  
Horincar ◽  
Furdui ◽  
Dinică
Keyword(s):  
Escherichia Coli ◽  
Triticum Aestivum ◽  
Seed Germination ◽  
Quaternary Ammonium ◽  
Pathogenic Bacteria ◽  
Classical Method ◽  
Triticum Aestivum L ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Radicle Growth

A family of fifteen quaternary ammonium salts (QAs), bearing the 1,2-bis(4-pyridyl)ethane core, were obtained using for the first time two different green methods, such as microwave (MW) and ultrasounds (US) irradiation, with very good yields and in much shorter times compared to the classical method, and an assay on their antimicrobial action against Escherichia coli (E. coli) was carried out. While 12 to 24 hours were required for complete alkylation of 1,2-bis(4-pyridyl)ethane by reactive halogenated derivatives in anhydrous solvent under reflux conditions, MW and US irradiation reduced the reaction time and the desired products were achieved in a few min. One of the aims of this study was to evaluate the antibacterial potential of the synthesized QAs against pathogenic bacteria, along with their impact on germination activity of wheat seeds (Triticum aestivum L.). The antibacterial activity of the QAs against Escherichia coli was explored by determining the minimum inhibitory concentration (MIC). The MIC values varied from 0.312 to 2.5 mg/mL, highlighting the lowest values attained for the derivatives containing methoxy, chlorine and benzofurane functional groups. The viability of aerobic bacteria was determined with the Tetrazolium/Formazan Test, a method that was found to be the best alternative approach with respect to the difuzimetric method. Seeds of Triticum aestivum L. were used for the evaluation of the germination indicators, such as seed germination (SG), the relative seed germination (RSG), the relative radicle growth (RRG), and the seed germination index (GI). The toxicity studies of QAs 1, 4 and 7, at two different concentrations, showed no inhibitory effect on seed germination.

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