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1.
Int J Mol Sci ; 22(9)2021 May 09.
Article in English | MEDLINE | ID: mdl-34065133

ABSTRACT

Low-molecular-weight organic ammonium salts exert excellent antimicrobial effects by interacting lethally with bacterial membranes. Unfortunately, short-term functionality and high toxicity limit their clinical application. On the contrary, the equivalent macromolecular ammonium salts, derived from the polymerization of monomeric ammonium salts, have demonstrated improved antibacterial potency, a lower tendency to develop resistance, higher stability, long-term activity, and reduced toxicity. A water-soluble non-quaternary copolymeric ammonium salt (P7) was herein synthetized by copolymerizing 2-methoxy-6-(4-vinylbenzyloxy)-benzylammonium hydrochloride monomer with N, N-di-methyl-acrylamide. The antibacterial activity of P7 was assessed against several multidrug-resistant (MDR) clinical isolates of both Gram-positive and Gram-negative species. Except for colistin-resistant Pseudomonas aeruginosa, most isolates were susceptible to P7, also including some Gram-negative bacteria with a modified charge in the external membrane. P7 showed remarkable antibacterial activity against isolates of Enterococcus, Staphylococcus, Acinetobacter, and Pseudomonas, and on different strains of Escherichia coli and Stenotrophomonas maltophylia, regardless of their antibiotic resistance. The lowest minimal inhibitory concentrations (MICs) observed were 0.6-1.2 µM and the minimal bactericidal concentrations (MBC) were frequently overlapping with the MICs. In 24-h time-kill and turbidimetric studies, P7 displayed a rapid non-lytic bactericidal activity. P7 could therefore represent a novel and potent tool capable of counteracting infections sustained by several bacteria that are resistant to the presently available antibiotics.


Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Benzylammonium Compounds/chemistry , Benzylammonium Compounds/pharmacology , Polymers , Anti-Bacterial Agents/chemical synthesis , Bacteria/drug effects , Benzylammonium Compounds/chemical synthesis , Chemistry Techniques, Synthetic , Dose-Response Relationship, Drug , Drug Resistance, Multiple, Bacterial/drug effects , Humans , Microbial Sensitivity Tests , Molecular Structure , Polymerization , Polymers/chemistry , Spectrum Analysis
2.
Chem Asian J ; 11(5): 782-8, 2016 Mar 04.
Article in English | MEDLINE | ID: mdl-26749383

ABSTRACT

The synthesis of N-benzyl- and N-cyclohexylammonium resorcinarene trifluoroacetate (TFA) and triflate (OTf) salt receptors was investigated. Solid-state analysis by single-crystal X-ray diffraction revealed that the N-alkylammonium resorcinarene salts (NARSs) with different upper substituents had different cavity sizes and different affinities for anions. Anion-exchange experiments by mixing equimolar amounts of N-benzylammonium resorcinarene trifluoroacetate and N-cyclohexylammonium resorcinarene triflate, as well as N-benzylammonium resorcinarene triflate and N-cyclohexylammonium resorcinarene trifluoroacetate showed that the NARS with flexible benzyl groups preferred the larger OTf anion, whereas the rigid cyclohexyl groups preferred the smaller TFA anions. The anion-exchange processes were confirmed in the solid state by single-crystal and powder X-ray diffraction experiments and in the gas phase by electrospray ionization mass spectrometry.


Subject(s)
Anions/chemistry , Calixarenes/chemistry , Mesylates/chemistry , Phenylalanine/analogs & derivatives , Salts/chemistry , Trifluoroacetic Acid/chemistry , Benzylammonium Compounds/chemistry , Crystallography, X-Ray , Dioxanes/chemistry , Models, Molecular , Phenylalanine/chemistry
3.
J Colloid Interface Sci ; 462: 341-50, 2016 Jan 15.
Article in English | MEDLINE | ID: mdl-26476203

ABSTRACT

Fabrication of Au nanostars (AuNSs) can expand the application range of Au nanoparticles because of their high electron density and localized surface plasmon resonance (LSPR) on branches. Exploiting this potential requires further refinement of length of the branches and radius of their tips. To this end, we successfully synthesized AuNSs with uniform and sharply-pointed branches by combining benzyldimethylammonium chloride (BDAC) and cetyltrimethylammonium bromide (CTAB) at low BDAC/CTAB ratios. Once mixed with CTAB, BDAC lowers the critical micelle concentration (CMC) for quick formation of the micelles, which provides favorable growth templates for AuNSs formation. Besides, BDAC increases the concentration of Cl(-), which favors Ag(+) in adsorbing on Au facets. This feature is crucial for the yield boosting and synergic shape control of AuNSs regardless of types of Au seeds used. Use of less amounts of seeds as the center of nucleation benefited sharper and longer growth of the branches. AuNSs exhibited excellent enhancement of surface-enhanced Raman scattering (SERS) intensities as the result of high electron density localized at the tips; however, the enhancement degree varied in accordance with the size of branches. In addition, AuNSs showed high catalytic performance toward the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Efficient catalysis over AuNSs originates from their corners, stepped surfaces and high electron density at the tips.


Subject(s)
Aminophenols/chemical synthesis , Benzylammonium Compounds/chemistry , Cetrimonium Compounds/chemistry , Gold/chemistry , Metal Nanoparticles/chemistry , Nitrophenols/chemistry , Aminophenols/chemistry , Catalysis , Cetrimonium , Micelles , Particle Size , Spectrum Analysis, Raman , Surface Properties
4.
Bioorg Med Chem ; 21(24): 7655-62, 2013 Dec 15.
Article in English | MEDLINE | ID: mdl-24238903

ABSTRACT

Several antiepileptic drugs exert their activities by inhibiting Na(+) currents. Recent studies demonstrated that compounds containing a biaryl-linked motif (Ar-X-Ar') modulate Na(+) currents. We, and others, have reported that compounds with an embedded benzyloxyphenyl unit (ArOCH2Ar', OCH2=X) exhibit potent anticonvulsant activities. Here, we show that benzyloxybenzylammonium chlorides ((+)H3NCH2C6H4OCH2Ar' Cl(-)) displayed notable activities in animal seizure models. Electrophysiological studies of 4-(2'-trifluoromethoxybenzyloxy)benzylammonium chloride (9) using embryonic cortical neurons demonstrated that 9 promoted both fast and slow inactivation of Na(+) channels. These findings suggest that the potent anticonvulsant activities of the earlier compounds were due, in part, to the benzyloxyphenyl motif and provide support for the use of the biaryl-linked pharmacophore in future drug design efforts.


Subject(s)
Anticonvulsants/chemistry , Anticonvulsants/pharmacology , Benzylammonium Compounds/pharmacology , Cerebral Cortex/drug effects , Neurons/drug effects , Phenyl Ethers/pharmacology , Seizures/drug therapy , Animals , Anticonvulsants/administration & dosage , Benzylammonium Compounds/administration & dosage , Benzylammonium Compounds/chemistry , Dose-Response Relationship, Drug , Mice , Molecular Structure , Phenyl Ethers/administration & dosage , Phenyl Ethers/chemistry , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship
5.
Org Lett ; 15(22): 5694-7, 2013 Nov 15.
Article in English | MEDLINE | ID: mdl-24180584

ABSTRACT

The first example of an oriented handcuff rotaxane has been obtained by through-the-annulus threading of a double-calix[6]arene system with a bis-ammonium axle. The relative orientation of the two calix-wheels can be predefined by exploiting the "endo-alkyl rule" which controls the directionality of the threading of alkylbenzylammonium axles with calixarene macrocycles.


Subject(s)
Benzylammonium Compounds/chemistry , Calixarenes/chemistry , Phenols/chemistry , Rotaxanes/chemical synthesis , Molecular Structure , Rotaxanes/chemistry
6.
Proc Natl Acad Sci U S A ; 110(7): 2490-5, 2013 Feb 12.
Article in English | MEDLINE | ID: mdl-23335629

ABSTRACT

Anion exchange membranes (AEMs) find widespread applications as an electrolyte and/or electrode binder in fuel cells, electrodialysis stacks, flow and metal-air batteries, and electrolyzers. AEMs exhibit poor stability in alkaline media; their degradation is induced by the hydroxide ion, a potent nucleophile. We have used 2D NMR techniques to investigate polymer backbone stability (as opposed to cation stability) of the AEM in alkaline media. We report the mechanism behind a peculiar, often-observed phenomenon, wherein a demonstrably stable polysulfone backbone degrades rapidly in alkaline solutions upon derivatization with alkaline stable fixed cation groups. Using COSY and heteronuclear multiple quantum correlation spectroscopy (2D NMR), we unequivocally demonstrate that the added cation group triggers degradation of the polymer backbone in alkaline via quaternary carbon hydrolysis and ether hydrolysis, leading to rapid failure. This finding challenges the existing perception that having a stable cation moiety is sufficient to yield a stable AEM and emphasizes the importance of the often ignored issue of backbone stability.


Subject(s)
Antiporters/metabolism , Cations/metabolism , Electrolytes/metabolism , Magnetic Resonance Spectroscopy/methods , Membranes, Artificial , Polymers/metabolism , Sulfones/metabolism , Benzylammonium Compounds/chemistry , Electrolysis , Electrolytes/chemistry , Molecular Structure , Polymers/chemistry , Sulfones/chemistry
7.
J Phys Chem B ; 116(22): 6425-30, 2012 Jun 07.
Article in English | MEDLINE | ID: mdl-22612584

ABSTRACT

Effects of a "gemini-type" organic salt 1,2-bis(2-benzylammoniumethoxy) ethane dichloride (BEO) on the aggregation behavior of sodium dodecylsulfate (SDS) have been investigated by turbidity, surface tension, isothermal titration microcalorimetry, dynamic light scattering, cryogenic transmission electron microscopy, (1)H NMR spectroscopy, and differential scanning microcalorimetry. The aggregation behavior of the SDS/BEO mixed aqueous solution shows strong concentration and ratio dependence. For the SDS/BEO solution with a molar ratio of 5:1, large loose irregular aggregates, vesicles, and long thread-like micelles are formed in succession with the increase of the total SDS and BEO concentration. Because BEO has two positive charges, the SDS/BEO solution may consist of the (SDS)(2)-BEO gemini-type complex, the SDS-BEO complex and extra SDS. The aggregation ability and surface activity of the SDS/BEO mixture exhibit the characteristics of gemini-type surfactants. Along with the results of DSC and (1)H NMR, the (SDS)(2)-BEO gemini-type structure is confirmed to exist in the system. This work provides an approach to construct the surfactant systems with the characteristics of gemini surfactants through intermolecular interaction between a two-charged organic salt and oppositely charged single-chain surfactants.


Subject(s)
Benzylammonium Compounds/chemistry , Sodium Dodecyl Sulfate/chemistry , Models, Molecular , Molecular Structure , Particle Size , Phase Transition , Salts/chemistry , Solutions , Surface Properties , Water/chemistry
8.
J Am Soc Mass Spectrom ; 23(5): 823-33, 2012 May.
Article in English | MEDLINE | ID: mdl-22367690

ABSTRACT

In this study, the fragmentation reactions of various N-benzylammonium and N-benzyliminium ions were investigated by electrospray ionization mass spectrometry. In general, the dissociation of N-benzylated cations generates benzyl cations easily. Formation of ion/neutral complex intermediates consisting of the benzyl cations and the neutral fragments was observed. The intra-complex reactions included electrophilic aromatic substitution, hydride transfer, electron transfer, proton transfer, and nucleophilic aromatic substitution. These five types of reactions almost covered all the potential reactivities of benzyl cations in chemical reactions. Benzyl cations are well-known as Lewis acid and electrophile in reactions, but the present study showed that the gas-phase reactivities of some suitably ring-substituted benzyl cations were far richer. The 4-methylbenzyl cation was found to react as a Brønsted acid, benzyl cations bearing a strong electron-withdrawing group were found to react as electron acceptors, and para-halogen-substituted benzyl cations could react as substrates for nucleophilic attack at the phenyl ring. The reactions of benzyl cations were also related to the neutral counterparts. For example, in electron transfer reaction, the neutral counterpart should have low ionization energy and in nucleophilic aromatic substitution reaction, the neutral counterpart should be piperazine or analogues. This study provided a panoramic view of the reactions of benzyl cations with neutral N-containing species in the gas phase.


Subject(s)
Benzylammonium Compounds/chemistry , Imines/chemistry , Mass Spectrometry/methods , Cations/chemistry , Electrons , Gases/chemistry , Piperazines/chemistry
9.
J Org Chem ; 75(21): 7373-80, 2010 Nov 05.
Article in English | MEDLINE | ID: mdl-20879776

ABSTRACT

The construction of a new series of dendritic tris(crown ether) hexagons via coordination-driven self-assembly is described. Combining 120° crown ether-containing diplatinum(II) acceptors with 120° dendritic dipyridyl donors in a 1:1 ratio allows for the formation of a new family of dendritic triple crown ether derivatives with a hexagonal cavity in quantitative yields. The number and the position of these pendant groups can be precisely controlled on the hexagonal metallacycle. The structures of all dendritic multiple crown ether hexgaons are confirmed by multinuclear NMR ((1)H and (31)P), ESI-MS and ESI-TOF-MS, and elemental analysis. The complexation of these dendritic trivalent receptors with dibenzylammonium cations was investigated by (1)H NMR titration experiments. The thermodynamic binding constants between the receptors and guests were established by using the nonlinear least-squares fit method based on (1)H NMR titration experiments. It was found that the association constants of each assembly decrease correspondingly upon the increase of the generation of the dendrons from [G0] to [G3], which might be caused by the steric effect of the dendrons on host-guest complexation.


Subject(s)
Benzylammonium Compounds/chemistry , Crown Ethers/chemistry , Dendrimers/chemistry , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Conformation
10.
J Org Chem ; 75(13): 4434-40, 2010 Jul 02.
Article in English | MEDLINE | ID: mdl-20527908

ABSTRACT

Remote intramolecular hydrogen bonds (HBs) in phenols and benzylammonium cations influence the dissociation enthalpies of their O-H and C-N bonds, respectively. The direction of these intramolecular HBs, para --> meta or meta --> para, determines the sign of the variation with respect to molecules lacking remote intramolecular HBs. For example, the O-H bond dissociation enthalpy of 3-methoxy-4-hydroxyphenol, 4, is about 2.5 kcal/mol lower than that of its isomer 3-hydroxy-4-methoxyphenol, 5, although group additivity rules would predict nearly identical values. In the case of 3-methoxy-4-hydroxybenzylammonium and 3-hydroxy-4-methoxybenzylammonium ions, the CBS-QB3 level calculated C-N eterolytic dissociation enthalpy is about 3.7 kcal/mol lower in the former ion. These effects are caused by the strong electron-withdrawing character of the -O(*) and -CH(2)(+) groups in the phenoxyl radical and benzyl cation, respectively, which modulates the strength of the HB. An O-H group in the para position of ArO(*) or ArCH(2)(+) becomes more acidic than in the parent molecules and hence forms stronger HBs with hydrogen bond acceptors (HBAs) in the meta position. Conversely, HBAs, such as OCH(3), in the para position become weaker HBAs in phenoxyl radicals and benzyl cations than in the parent molecules. These product thermochemistries are reflected in the transition states for, and hence in the kinetics of, hydrogen atom abstraction from phenols by free radicals (dpph(*) and ROO(*)). For example, the 298 K rate constant for the 4 + dpph(*) reaction is 22 times greater than that for the 5 + dpph(*) reaction. Fragmentation of ring-substituted benzylammonium ions, generated by ESI-MS, to form the benzyl cations reflects similar remote intramolecular HB effects.


Subject(s)
Benzylammonium Compounds/chemistry , Cations/chemistry , Phenols/chemistry , Hydrogen Bonding , Models, Molecular , Molecular Structure
11.
Biotechnol J ; 5(2): 192-200, 2010 Feb.
Article in English | MEDLINE | ID: mdl-20108274

ABSTRACT

In this study, nanoporous gold supercapacitors were produced by electrochemical dealloying of gold-silver alloy. Scanning electron microscopy and energy dispersive X-ray spectroscopy confirmed completion of the dealloying process and generation of a porous gold material with approximately 10 nm diameter pores. Cyclic voltammetry and chronoamperometry of the nanoporous gold electrodes indicated that these materials exhibited supercapacitor behavior. The storage capacity of the electrodes measured by chronoamperometry was approximately 3 mC at 200 mV. Electrochemical storage and voltage-controlled delivery of two model pharmacologic agents, benzylammonium and salicylic acid, was demonstrated. These results suggest that capacitance-based storage and delivery of pharmacologic agents may serve as an alternative to conventional drug delivery methods.


Subject(s)
Drug Delivery Systems/methods , Electrodes , Gold/chemistry , Nanotechnology/methods , Silver/chemistry , Benzylammonium Compounds/chemistry , Electric Capacitance , Microscopy, Electron, Scanning , Particle Size , Porosity , Salicylates/chemistry
12.
Chem Commun (Camb) ; (7): 817-9, 2008 Feb 21.
Article in English | MEDLINE | ID: mdl-18253514

ABSTRACT

We have used the "threading-followed-by-swelling" approach to fix a daisy chain structure in solution, leading to the isolation of a captured [c2]daisy chain in 77% yield.


Subject(s)
Benzylammonium Compounds/chemistry , Macrocyclic Compounds/chemistry , Benzylammonium Compounds/chemical synthesis , Crystallography, X-Ray , Hydrogen Bonding , Macrocyclic Compounds/chemical synthesis , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Structure
13.
Z Naturforsch C J Biosci ; 61(3-4): 302-8, 2006.
Article in English | MEDLINE | ID: mdl-16729594

ABSTRACT

Effects of N-dodecyl-N,N-dimethyl-N-benzylammonium halides (DBeAX) on thermotropic phase behavior of phosphatidylcholine/cholesterol bilayers as well as on 1H NMR spectra were studied. The surfactants were added either to the water phase or directly to the lipid phase (a mixed film was formed). The benzyl group, opposite to liposomes without cholesterol, is not incorporated into the bilayer in the gel state but only in the liquid state. All the halides DBeAX (particularly the chloride DBeAC) showed greater ability to destabilize the membrane structure in the presence than in the absence of cholesterol. The interaction of DBeAX with DPPC/cholesterol bilayers and subsequent changes in the phospholipid bilayer organization depended on the kind of counterion. The strongest effects were observed for chloride (most electronegative ion) and for iodide (largest ion). The effects of chloride and bromide on phase transition and 1H NMR spectra in the presence and absence of cholesterol were opposite. This is discussed in terms of the influence of counterions on the pair cholesterol-DPPC interactions.


Subject(s)
Benzylammonium Compounds/chemistry , Cholesterol/chemistry , Phosphatidylcholines/chemistry , 1,2-Dipalmitoylphosphatidylcholine/chemistry , Lipid Bilayers/chemistry , Magnetic Resonance Spectroscopy , Structure-Activity Relationship
14.
J Org Chem ; 71(6): 2373-83, 2006 Mar 17.
Article in English | MEDLINE | ID: mdl-16526786

ABSTRACT

We report a new host molecule in which one diethylene glycol chain (i.e., a loop possessing only three oxygen atoms) incorporated along with two phenolic aromatic rings is linked by a xylene spacer into a macroring. The design of the molecular structure of this macrocycle "amplifies" any potential [cation...pi], [N+-H...pi], and [N+C-H...pi] interactions between the dibenzylammonium (DBA+) ion and the phenolic rings of the macrocycle; as such, these species display a very strong binding affinity in CD3NO2 (Ka = 15,000 M(-1)). The macroring also coordinates to bipyridinium ions in a [2]pseudorotaxane fashion, which makes it the smallest macrocycle (i.e., a 25-membered ring) known to complex both DBA+ and bipyridinium ions in solution. To confirm unambiguously that these pseudorotaxanes exist in solution, we synthesized their corresponding interlocked molecules, namely rotaxanes and catenanes.


Subject(s)
Benzylammonium Compounds/chemistry , Macrocyclic Compounds/chemistry , Benzylammonium Compounds/chemical synthesis , Hydrogen Bonding , Macrocyclic Compounds/chemical synthesis , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Structure , Sensitivity and Specificity , Stereoisomerism
15.
Org Biomol Chem ; 2(21): 3071-4, 2004 Nov 07.
Article in English | MEDLINE | ID: mdl-15505709

ABSTRACT

The effect of the amidinium group and the phenyl ring on the thermodynamics of binding of benzamidinium chloride to the serine proteinase trypsin has been studied using isothermal titration calorimetry. Binding studies with benzylammonium chloride, [small alpha]-methylbenzylammonium chloride and benzamide, compounds structurally related to benzamidinium chloride, showed that hydrogen bonding between the amidinium group and the enzyme is primarily enthalpy-driven. Binding of cyclohexylcarboxamidinium chloride and acetamidinium chloride showed that the hydrophobic binding of the phenyl ring in the S1 pocket is primarily entropy-driven and that a rigid, flat hydrophobic binding site for the inhibitor is favourable. The compounds that have been studied over a range of temperatures exhibit a negative change in heat capacity upon binding and enthalpy-entropy compensation, both characteristic of hydrophobic interactions.


Subject(s)
Benzylammonium Compounds/chemistry , Trypsin/chemistry , Benzylammonium Compounds/metabolism , Crystallization , Thermodynamics , Trypsin/metabolism
16.
Molecules ; 9(10): 825-9, 2004 Sep 30.
Article in English | MEDLINE | ID: mdl-18007482

ABSTRACT

N-Methylbenzylammonium fluorochromate(VI) (MBAFC) is easily synthesized by addition of N-methylbenzylamine to an aqueous solution of CrO3 and HF. MBAFC shows selectivity in the oxidation of aryl alcohols to their corresponding aldehydes and ketones under mild conditions. The durability, ease of work up and efficiency of MBAFC are considerably increased upon its absorption on silica gel.


Subject(s)
Benzenesulfonates/chemical synthesis , Benzylammonium Compounds/chemical synthesis , Carbocyanines/chemical synthesis , Oxidants/chemical synthesis , Silicon Dioxide , Benzenesulfonates/chemistry , Benzylammonium Compounds/chemistry , Carbocyanines/chemistry , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/chemistry , Oxidants/chemistry
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