Ammonium Betaines Research Articles

Zwitterionic sulfobetaine-based hypercrosslinked hydrophilic materials for bioanalysis

Analysis of bioactive polar molecules is crucial for different fields, including biology, clinic medicine, and separation science. However, the design of the separation materials remains a huge challenge due to their tedious preparation process and limited chromatographic performances of traditional hydrophilic materials. New-generation hydrophilic polymer materials prepared via a sole-monomer system exhibit excellent reproducibility and chromatographic efficiency; however, such polymers reported to date have a high swelling propensity and risk of low surface exposure of functional groups, which limit their application as separation materials. In this study, N,N-bis(methacryloxyethyl)-N-methyl-N-(3-sulfopropyl)ammonium betaines (BMMSB), a zwitterionic sulfobetaine, was used to rapidly fabricate the zwitterionic hypercrosslinked hydrophilic polymer materials via the sole-monomer system. The novel hypercrosslinked hydrophilic materials exhibited high porosity and permeability, superhydrophilicity, low protein adsorption, and excellent capillary column efficiency (up to 134,950 plates/m for thiourea). It was able to enrich 28 N-glycopeptides from hIgG tryptic digests with a higher efficiency than that of traditional poly(SPE-co-EDMA) monolith and commercial ZIC-HILIC materials. Additionally, the polyBMMSB hydrophilic materials demonstrated superior selectivity and column efficiency to the poly(SPE-co-EDMA) monolith for the separation of various small bioactive molecules, including nucleobases and nucleosides, phenol derivatives, benzoic acid derivatives, urea and allantoin. Especially, high performance bioanalysis of Alzheimer’s disease biomarkers plasma Aβ42 and Aβ40, or some steroid hormones in human plasma were also achieved by the polyBMMSB monolith combined with nano liquid chromatography-mass spectrometry. As such, these sulfobetaine-based zwitterionic polymers may serve as a prototypical next-generation zwitterionic hydrophilic materials for rapid and efficient bioanalysis.

Chemistry of Ammonium Betaines: Application to Ion-Pair Catalysis for Selective Organic Transformations

Chemistry of Ammonium Betaines: Application to Ion-Pair Catalysis for Selective Organic Transformations

Stereoselective Aza-Henry Reaction of 3-Nitro-dihydro-2(1H)-quinolones with N-Boc-Aldimines under the Catalysis of Chiral Ammonium Betaines

Stereoselective Aza-Henry Reaction of 3-Nitro-dihydro-2(1H)-quinolones with N-Boc-Aldimines under the Catalysis of Chiral Ammonium Betaines

Chiral ammonium betaine-catalyzed asymmetric Mannich-type reaction of oxindoles

A highly diastereo- and enantioselective Mannich-type reaction of 3-aryloxindoles with N-Boc aldimines was achieved under the catalysis of axially chiral ammonium betaines. This catalytic method provides a new tool for the construction of consecutive quaternary and tertiary stereogenic carbon centers on biologically intriguing molecular frameworks with high fidelity.

Vinylogy in nitronates: utilization of α-aryl conjugated nitroolefins as a nucleophile for a highly stereoselective aza-Henry reaction.

The vinylogous reactivity of α,β-disubstituted nitroolefins was uncovered through the facile generation of the corresponding α-substituted vinylogous nitronates and their use in the development of a highly diastereo- and enantioselective aza-Henry reaction with N-Boc aldimines under the catalysis of chiral ammonium betaines. The novel vinylogous nitronates undergo stereoselective bond formation at the sterically encumbered α-position exclusively, allowing the construction of contiguous tertiary-quaternary stereogenic carbon centers.

Ammonium betaines: efficient ionic nucleophilic catalysts for the ring-opening polymerization of L-lactide and cyclic carbonates.

The ionic nucleophilic character of ammonium betaine catalysts allows for controlling the ROP of L-LA for DP as high as 750 with very narrow dispersity values (≤1.18). Compared to ionic nucleophilic and hydrogen-bonding based catalysts for ROP, meta-betaine combines the positive aspects of both processes in terms of kinetics and selectivity. The versatility of ammonium betaines was evidenced by varying the nature of the initiating alcohol and monomer used.

Dilute solution properties of some polycarboxybetaines with antibacterial activity

The dilute solution properties of polymeric quaternary ammonium betaines derived from poly(N-vinylimidazole) PNVI and containing either a methylene (B1), ethylene (B2), or propylene (B3) betaine group, respectively, were analyzed. A PNVI blank was also tested. The weight-average molecular weight \( {{\overline{M}}_{\text{w}}} \), second virial coefficient A2, radius of gyration Rg, and hydrodynamic radius Rh of unfractionated probes were determined by MALLS (multiangle laser light scattering) and WALLS (wide-angle laser light scattering) measurements. All of these parameters varied with the type of solvent: pure water, an aqueous solution of 0.5 M NaCl, or an alcohol. These solution properties were useful for predicting the interactions of the polycarboxybetaines (acting as antimicrobial agents) with the components of the bacterial cell wall. Some of the polycarboxybetaines exhibited antimicrobial activities, as shown by the Kirby–Bauer diffusion method. A concentration of about 20 mg mL−1 for B1 or B3 in an aqueous solution of 0.5 M NaCl is sufficient to inhibit the growth of Escherichia coli.

ChemInform Abstract: Nitroolefins as a Nucleophilic Component for Highly Stereoselective Aza Henry Reaction under the Catalysis of Chiral Ammonium Betaines.

AbstractThe ammonium‐betain catalyzed aza Henry reaction of in situ generated chiral vinylogous nitronates with N‐Boc imines is reported.

ChemInform Abstract: Ionic Nucleophilic Catalysis of Chiral Ammonium Betaines for Highly Stereoselective Aldol Reaction from Oxindole‐Derived Vinylic Carbonates.

AbstractA new strategy for developing stereoselective C‐C bond formation reactions is introduced.

Nitroolefins as a Nucleophilic Component for Highly Stereoselective Aza Henry Reaction under the Catalysis of Chiral Ammonium Betaines

The ammonium-betain catalyzed aza Henry reaction of in situ generated chiral vinylogous nitronates with N-Boc imines is reported.

Stereoselective Aldol Reaction Catalyzed by Ammonium Betaines

Stereoselective Aldol Reaction Catalyzed by Ammonium Betaines

Weak Intermolecular Anion–π Interactions in Pentafluorobenzyl‐Substituted Ammonium Betaines

AbstractA series of ammonium–carboxylate and ammonium–sulfonate betaines was synthesized and studied by single‐crystal X‐ray diffraction analysis to investigate the weak intermolecular interactions as well as the intramolecular interactions in the solid state. None of the expected intramolecular anion–π interactions could be observed, probably because of the steric demands and the reduced nucleophilicity of the anionic part of the betaines. Nevertheless, a weak intermolecular anion–π interaction between the anionic part of the betaine and the pentafluorophenyl unit is present in the structure of 5a.

Ionic Nucleophilic Catalysis of Chiral Ammonium Betaines for Highly Stereoselective Aldol Reaction from Oxindole-Derived Vinylic Carbonates

A new strategy for developing stereoselective bond-forming reactions is introduced; it takes advantage of the ionic nucleophilic catalysis of chiral ammonium betaines to utilize vinylic esters simultaneously as the enolate precursor and the acylating agent for coupling with electrophiles. Its synthetic utility is clearly demonstrated by the realization of a highly diastereo- and enantioselective aldol reaction from oxindole-derived vinylic carbonates.

Zwitterionic hydrogels crosslinked with novel zwitterionic crosslinkers: Synthesis and characterization

Two novel zwitterionic sulfobetaine dimethacrylate crosslinkersN,N-bis(methacryloxyethyl)-N-methyl-N-(3-sulfopropyl)ammonium (CL1) and N,N-bis(methacryloxyethyl)-N-methyl-N-(4-sulfobutyl)ammonium (CL2) betaines were synthesized and used for preparation of zwitterionic hydrogels formed from N-(methacryloxyethyl)-N,N-dimethyl-N-(3-sulfopropyl)ammonium betaine (SBDMA) via redox-initiated free-radical polymerization. The commercially available crosslinkers N,N′-methylene bisacrylamide (BIS) and ethylene glycol dimethacrylate (EDMA) were also used. Equilibrium water content, sorption degree, diffusion coefficient of water, state of water, degree of crosslinking and mechanical properties were determined for hydrogels crosslinked using different crosslinking conditions. A minor difference in the spacer length between the charged moieties in CL1 and CL2 crosslinkers, respectively, was shown to influence the hydrogel properties. The CL1 and CL2 crosslinkers with chemical structure similar to SBDMA resulted in hydrogels with higher stiffness, mechanical strength and crosslink density compared to hydrogels crosslinked by BIS and EDMA. This difference was assigned to suppression of the compositional drift during the hydrogel formation when crosslinkers with chemical structure similar to monomer were used. PolySBDMA hydrogels exhibited a low adhesion of RAT-2 fibroblasts-like cells.

ChemInform Abstract: Chiral Ammonium Betaines as Ionic Nucleophilic Catalysts.

AbstractChiral betaine NAB is a highly enantioselective catalyst for the Steglich rearrangement of oxazolyl trichloroethyl carbonates (I) providing oxazolones bearing a quaternary stereogenic carbon atom.

Chiral Ammonium Betaines as Ionic Nucleophilic Catalysts

Ungeahnte Qualitäten: Das chirale Ammoniumbetain 1 war als ionischer nucleophiler Katalysator in der asymmetrischen Steglich-Umlagerung erfolgreich. Die Umsetzung ergab rekordverdächtige Enantioselektivitäten und war auf vielfältige Substrate anwendbar. M.S. = Molekularsieb, Troc = 2,2,2-Trichlorethoxycarbonyl.

Chiral Ammonium Betaines as Ionic Nucleophilic Catalysts

Chiral betaine NAB is a highly enantioselective catalyst for the Steglich rearrangement of oxazolyl trichloroethyl carbonates (I) providing oxazolones bearing a quaternary stereogenic carbon atom.

Performance of C1-symmetric chiral ammonium betaines as catalysts for the enantioselective Mannich-type reaction of α-nitrocarboxylates

The catalytic performance of C 1-symmetric chiral ammonium betaines in the enantioselective direct Mannich-type reaction of α-nitrocarboxylates with N-Boc imines has been investigated. The most effective catalyst structure has been identified; this provides a reliable synthetic route to a variety of enantiomerically enriched α-tetrasubstituted α,β-diamino acid derivatives.

Improved methods of analysis for betaines in Ascophyllum nodosum and its commercial seaweed extracts

Beneficial effects of seaweeds and their extracts on crop performance have been attributed to a variety of compounds, including the betaines which are quaternary ammonium betaines. Methods of analysis of betaines published thus far suffer from low sensitivity, lack of baseline separation of individual betaines and from interference from other sample constituents. A rapid cleanup protocol and a sensitive LC-MS/MS method of analysis were developed to afford baseline separation of four betaines in the brown alga Ascophyllum nodosum and its commercial seaweed extract. Using this method, the presence of glycine betaine, δ-aminovaleric acid betaine, γ-aminobutyric acid betaine and laminine in A. nodosum, and commercial extracts derived from A. nodosum, were confirmed and quantified. The major betaine present was γ-aminobutyric acid betaine accounting for 0.008–0.014% of the dry weight of the seaweed and 0.014–0.027% of the dry weight of the commercial extracts. Seasonal variation in betaine content was observed. Differences in the total betaine content were observed between A. nodosum of the yellow (0.011–0.017% dry weight) and the olive green (0.017–0.021% dry weight) coloured morphologies.

ChemInform Abstract: Chiral Ammonium Betaines: A Bifunctional Organic Base Catalyst for Asymmetric Mannich‐Type Reaction of α‐Nitrocarboxylates.

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