Quarternary Ammonium Salts Research Articles

Synthesis and Skin Permeation Study of Lidocaine Organic Salts

Four organic quarternary ammonium salts of lidocaine, lidocaine adipate, lidocaine maleate, lidocaine malonate and lidocaine tosylate were prepared in this study. These compounds were regarded as prodrugs of lidocaine and were expected to enhance skin permeability by ion-pair approach. In vitro permeation study through pig skin and determination of partition coefficients were carried out. The skin permeation of lidocaine adipate and lidocaine malonate after 12 hours of application was significantly higher than lidocaine hydrochloride but was not significantly different from lidocaine (α < 0.05). The increase in permeation of organic salts from lidocaine hydrochloride and the different profile of permeation from lidocaine may be the result of prodrug structure contributing ion-pair transportation beside normal route of transportation.

Adsorption of oligonucleotides onto polyisohexylcyanoacrylate nanoparticles protects them against nucleases and increases their cellular uptake.

Oligonucleotides can be adsorbed on polyisohexylcyanoacrylate nanoparticles in the presence of hydrophobic quarternary ammonium salts. Oligonucleotides bound to nanoparticles are protected from nuclease attack both in buffer and in cell culture media. Cellular uptake of oligonucleotides is increased when they are adsorbed onto nanoparticles as a result of the capture of nanoparticles by an endocytic phagocytic pathway. Intracellular stability towards nucleolytic degradation is increased in the presence of nanoparticles. These results show that nanoparticles can be considered as convenient carriers for the protection and delivery of oligonucleotides to cells.

Effect of supporting electrolytes and cathode materials on the electro-copolymerization of acrylonitrile with methacrylic acid

Copolymers of acrylonitrile with methacrylic acid were synthesized electrochemically. The reaction system consisted of dimethyl formamide as solvent and various quarternary ammonium salts as supporting electrolytes. The influences of supporting electrolytes and electrode materials on the compositions of the copolymers were investigated. The copolymers were characterized by i.r., NMR and elemental analyses. Thermal decomposition studies of the polymer in air are also discussed.

Kinetics of the extraction of phenylalanine and glutamic acid by ion-exchange carriers

Biological transport of amino acids is usually mediated by carrier proteins buried in biomembranes. The application of models to such transport systems has long been desired in the separation science and technology of amino acids and is an active area of research. Recently, the application of commercial metal extractants as mobile carriers in the liquid membrane technology has attracted increasing attention due to their potential capability in the field of bioseparation. In the development of such a novel separation technique, knowledge of the extraction kinetics is necessary in addition to knowledge of the extraction equilibrium. Due to their zwitterionic character, it is possible to extract amino acids with ion-exchange carriers by controlling the pH of aqueous amino acid solutions. A modified Lewis-type cell experiment was used to study the extraction kinetics of glutamic acid (system I) and phenylalanine (system II) by naphthenic acid, and that of phenylalanine by a quarternary ammonium salt, Aliquat 336 (system III). The effects of agitation, interfacial area, carrier concentration, pH, and initial concentration of amino acids on the extraction rate were discussed. A rate equation involving the mass transfer terms was derived, based on an interfacial chemical reaction mechanism. It was found that the limiting case, based on an interfacial reaction rate-determining mechanism, was in good agreement with the experimental results. The intrinsic chemical reaction is controlled by the formation of an amino acid/ carrier complex at the interface. The mechanism of extraction proposed in this study is applicable to both glutamic acid and phenylalanine in the two ionic carrier systems.

Interaction of p-nitrophenol with lipids at hydrophobic interfaces

Adsorption of p-nitrophenol (PNP) at two model hydrophobic interfaces, namely at air/solution interface and mercury electrode/solution interface, as well as its interaction with neutral and charged lipids has been studied in monolayers by light reflection spectroscopy and electrochemical methods. Investigations have been performed at pH=10 and pH=11 wher the dissociated form of PNP carrying a negative charge is predominant. In this pH region no accumulation of PNP from bulk solution to the free air/solution interface and slight adsorption at mercury surface was observed. PNP also does not accumulate in neutral phospholipid monolayers spread at the air/solution interface while phospholipid layers formed at mercury by adsorption from the bulk solution cause the inhibition of electrochemical reduction of PNP. The attachment of PNP to the neutral phospholipid layer is enhanced and accelerated at both interfaces by the presence of quarternary ammonium salts in the solution.

Bilayer characteristics and cholesterol effects of sodium dialkylmethyl sulphates

AbstractThe gel‐liquid crystal phase transitions (PT) in bilayers formed from a series of synthetic sodium dialkylmethyl sulphates have been studied by both fluorescence and differential scanning calorimetry (DSC) methods, which are between the transitions of the corresponding phospholipids and the quarternary ammonium salt bilayers possessing the same hydrocarbon chains. The fluorescence I3/I2 ratio (R) of probe pyrene in the bilayers decreases below and increases above the transitions respectively with increasing the chain length of the surfactants in the series SUDS, SPHS, and SHOS. In addition, the difference between the R above and below the transition (ΔR) is larger in the suspension prepared at the temperature above that of the transition than in that formed at room temperature. Intermembrane transfer and transbilayer migration (flip‐flop) evaluated by means of DSC of a mixture of equimolar aqueous dispersions of SHOS and SPHS as well as by ESR of bilayer embedding the stable free radical 4‐HD‐TEMPO in the presence and absence of excess ascorbic acid take place noticeably only at the temperature above that of the transitions. Cholesterol has shown the same effect on ΔR as to decrease the length of the alkyl chain of the surfactants. It also causes a decrease of the fluorescence Intensity ratio of excimer to monomer of pyrene, Ie/Im(S), in both phase. The results are discussed in terms of bilayer structure, chain fluidity, and permeability of water.

Permethylation and tandem mass spectrometry of oligosaccharides having free hexosamine: Analysis of the glycoinositol phospholipid anchor glycan from the scrapie prion protein

Permethylation of the glycan isolated from the glycoinositol phospholipid (GPI) anchor of the scrapie prion protein (PrP Sc) trimethylates a free hexosamine to form a quarternary ammonium salt, substantially increasing the sensitivity for analysis by mass spectrometry. This derivatization induces specific fragmentation reactions in collision-induced dissociation spectra obtained on a four-sector tandem mass spectrometer, identifying the branching pattern of the PrP Sc GPI glycan.

ChemInform Abstract: Ferrocene Derivatives. Part 24. Synthesis of Dihydro-2-pyrindines and Dihydro-3H-2-cyclopent(c)azepines by Photolysis of Their Cyclopentadienyliron Derivatives.

Bischler-Napieralski type cyclizations of N-acyl-2-ferrocenylethylamine and N-acyl-3-ferrocenylpropylamine lead respectively to cyclopentadienyl(dihydro-2-pyrindin-5-yl)iron and cyclopentadienyl(tetrahydrocyclopent[c]azepine)iron derivatives. Photolysis of their quarternary ammonium salts liberates the metal-free azabicyclic systems.

Selectivity in Alkylation of Phenols with 1-Bromo-3-chloropropane Using Phase-Transfer Catalysis

The use of various phase-transfer catalysts in the alkylation of phenol and substituted phenols with 1-bromo-3-chloropropane was investigated. When a quarternary ammonium salt of the general formula R′4N+ X-, where R′ = alkyl with a minimum chain length of 4 was used, a mixture of 1-aryloxy-3-chloropropane and 1-aryloxy-3-bromopropane resulted. The effect of counterion, added potassium bromide, and catalysts other than quarternary ammonium salts were assessed for the halopropylation of 2,5-dimethylphenol.

Synthesis and thermal self‐crosslinking reaction of copolymers from 2,3‐epoxypropyl methacrylate and p‐substituted phenyl methacrylates

AbstractCopolymers of 2,3‐expoxypropyl (glycidyl) methacrylate (GMA) with various phenyl methacrylates such as 4‐nitrophenyl methacrylate (NPMA), 4‐chlorophenyl methacrylate (CPMA), or phenyl methacrylate (PMA), and other monomers such as methyl methacrylate (MMA), ethyl acrylate (EA), or styrene (ST) were synthesized by radical copolymerization, and then thermal self‐crosslinking reactions of the obtained copolymers were carried out using various catalysts such as quarternary ammonium salts, tert‐amines, or the crown ether/potassium salt systems at 100–150°C. Although the copolymer of GMA–NPMA–MMA does not produce any gel products without catalyst upon heating at 110°C for 5 h, this copolymer gives gel products in 82% yield using 10 mol% of tetrabutylammonium bromide as a catalyst under the same conditions. The rate of gel production of the copolymer of NPMA is faster than those of copolymers of CPMA and PMA. The rate of the gel production of the copolymer of GMA–NPMA–EA is also faster than those of copolymers of MMA and ST. Furthermore, it was found that the rate of gel production of the copolymer was strongly affected by the kind of catalyst, the catalyst concentration, and the reaction temperature.

Reactivity of 7-dithiocarboxy-imidazo[2,1-b]thiazoliumbetaine with aliphatic alkylating agents

We have reported earlier on the reactivity of 7-dithiocarboxy-3-phenyl-5,6-dihydro imidazo[2,1-b]thiazolium-betaine with severalpara-substituted phenacyl bromides. In this work reactions of 7-dithiocarboxy-3-phenyl(or methyl)-5,6-dihydro imidazo[2,1-b]thiazolium-betaine with a series of aliphatic alkylating agents of α-halo ketone, γ-halo keto ester and α-halo ester were examined for the similar purpose. In case of α-halo ketone or γ-halo keto ester such as α-chloro acetone or ethyl 4-chloro acetoacetate new biheterocyclic compound was obtained via ring transformation reaction. However, reaction of the betaine with methyl(or ethyl) bromoacetate used as a α-halo ester, gave, instead, S-alkylated quarternary ammonium salt.

ANION EXCHANGE EXTRACTION AND ENRICHMENT FROM AQUEOUS SOLUTIONS BY QUARTERNARY AMMONIUM REAGENTS

ABSTRACT The problems of solvent extraction and ion-exchange-based quantitative enrichment of anions having high hydration energies in aqueous solutions using water-insoluble quaternary ammonium salts are discussed. A new approach to anion exchange extraction of such anions by water-soluble polymeric quarternary ammonium salts is suggested in conjunction with membrane filtration. The retention of oxo anions of arsenic(V)r phosphorus(V), chromium(VI), selenium(IV) and of the fluoride ion with the permethylated derivative of poly-(ethyleneimine) and the influence of different salts on the retention of the anions have been studied and the possibility of quantitative retention of these anions has been demonstrated. For example, the retention for arsenic(V) was found to be 92% and 89% for fluoride with 2% polymer and a filtration factor of seven. After extraction the oxo anions can be stripped off easily in the cell solution up to 99% by 0.1 M HCl or a 0.15 M solution of sodium salts.

Ferrocene derivatives. Part 24. Synthesis of dihydro-2-pyrindines and dihydro-3H-2-cyclopent[c]azepines by photolysis of their cyclopentadienyliron derivatives

Bischler-Napieralski type cyclizations of N-acyl-2-ferrocenylethylamine and N-acyl-3-ferrocenylpropylamine lead respectively to cyclopentadienyl(dihydro-2-pyrindin-5-yl)iron and cyclopentadienyl(tetrahydrocyclopent[c]azepine)iron derivatives. Photolysis of their quarternary ammonium salts liberates the metal-free azabicyclic systems.

Studies on the Catalyst for the Production of N, N-Dimethyl (Long-chain Alkyl Amines)

N, N-dimethyl(long-chain alkylamines)are one of the most important fatty chemicals, far example, as the industrial intermediates which are derived to many commercial products such as the quarternary ammonium salts, amine oxide and so forth. These N, N-dimethyl (long-chain alkylamines)have been synthesized from the corresponding alcohols economically over many kinds of heterogeneous catalysts. But these catalysts are not satisfactory enough both in activity and selectivity.The mechanism of the amination of alcohols has been investigated for a long time, and required the dehydrogenation and hydrogenolysis abilities of the catalysts used in this reaction.We, in this work, planned to use copper as the catalyst for dehydrogenation and nickel as that far hydrogenolysis, and found Cu-Ni catalyst supported on SiO2/Al2O3 gave very high activity and selectivity in the amination of dodecyl alcohol. When the weight ratio of Cu/Ni was 4/1, it gave the maximum of activity and selectivity.The valence states of surface metals of the catalyst were analyzed by using ESCA. Copper was reduced to Cu0 or Cu+ in the hydrogen atmosphere at 200°C. Nickel was not reduced in the same atmosphere.When there was much amount of Ni2+ on the catalyst surface, the selectivity for the amination reaction was low, Ni2+ was seemed to accelerate the disproportionation of dimethylamine (DMA).

Chemistry of epoxide–polycarbonate copolymer networks

AbstractDiepoxides and in‐chain carbonate groups react readily in the presence of quarternary ammonium salts, although reaction is not observed without this catalyst. Two moles of epoxide react with each mole of carbonate. When diepoxides and polycarbonates are reacted, a three‐dimensional network of chains crosslinked with carbonate groups is produced; the crosslink density is controlled by adjusting the epoxy/carbonate ratio. Tertiary amines and alkoxides also catalyze the epoxy/carbonate reaction, but these have the undesirable attribute of promoting epoxy polymerization. The presence of oligocarbonates accelerates the epoxy–amine reaction.

Thermotropic Liquid Crystalline Character and Vesicular Properties of Some Functionalized Long-Chain Di-n-dodecyl Quaternary Ammonium Salts

Abstract In several reports it has been shown that amphiphilic molecules, including phospholipids, which aggregate in solution to form micelles, vesicles or liposomes also exhibit thermotropic liquid crystalline phases. In conjunction with our recent work on the synthesis and characterization of vesicle-forming monomeric and polymerized allyl and diallyl di-n-alkyl quarternary ammonium salts, a series of analogously functionalized derivatives has been prepared. Di-n-dodecyldimethyl quarternary ammonium bromide was employed as the parent compound. The new quarternary ammonium salts were formed by replacing one or both of the methyl groups in the parent compound by groups such as—CH2—CH=CH2,—CH2CH2OH,—CH2COOH,—CH2CH2COOH, or—CH2CH2CH2CN. The existence of liquid crystalline phases in these quarternaries was established by optical microscopy while transition temperatures as well as thermodynamic parameters were determined by DSC. Some of these compounds when dispersed in water and sonicated ultimately formed ...

New thermo‐crosslinking reactions of polymers containing pendant epoxide groups with various polyfunctional active esters

AbstractNew thermo‐crosslinking reactions of poly(glycidyl methacrylate), copolymers of glycidyl methacrylate with methyl methacrylate, styrene or ethyl acrlate with various active esters such as di[S‐(2‐benzothiazoly)] thioadipate (BTAD), di(S‐phenyl) thioadipate (PTAD), di(4‐nitrophenyl) adipate (NPAD), diphenyl adipate (PAD), and di(S‐phenyl) thioisophthalate (PTIP), and other polyfunctional esters were carried out in the film state using various catalysts such as quarternary ammonium or phosphonium salts, tert amines, or the crown ether 18‐crown‐6 = potassium salts system. Addition reactions of pendant epoxide groups in the polymer with the active esters such as NPAD and PTAD proceeded selectively to give gel compounds without other side reactions. The rates of reaction with the thioesters such as BTAD and PTAD were relatively faster than those with the phenyl esters such as PAD and NPAD at 70°C. The rates of reactions with the esters having flexible segments such as PTAD were also faster than those with the esters having rigid skeletons such as PTIP. Furthermore, it was found that the rate of reaction was affected strongly by reaction temperature, catalyst concentration, length of alkyl chain in the catalyst, kind of counterion of quarternary ammonium salts as a catalyst, content of pendant epoxide groups in the polymer, and kind of copolymer unit in the polymer, respectively.

Polymerization by phase transfer catalysis—5. Polycarbonates from diphenols with aromatic side groups

Polycarbonates were synthesized from phosgene and three different diphenols under phase transfer conditions, using quarternary ammonium and phosphonium salts and dichloromethane as solvent. The polycarbonates were characterized by i.r. and 1H-NMR; the molecular weights were estimated from inherent viscosity measurements. The influences of the catalysts and the structure of the diphenol were studied; both exert an important effect on the molecular weights. The hydrolysis of the polycarbonates was studied by the variation of the η inh values, the polymer undergoes a hydrolytic process in the organic phase, influenced by the catalysts, according to their structure.

Modified clays for organic waste disposal

Abstract Montmorillonite clays exchanged with a number of quarternary ammonium salts were examined for their adsorption capacities for phenols and chlorophenols. The exchanged clays with the best adsorption capacities were solidified with cement and the chemical leaching and physical characteristics of the subsequent products examined. The results indicated that the use of such clays as additives to cement‐based solidification processes could prove of considerable importance for the future of stabilization/solidification of hazardous organic wastes.

An unusual transformation of 2-pentafluorophenoxyethyl-N,N-diethylamine with alkyl bromides and alkyl iodides to form piperazinium salts and alkyl pentafluorophenyl ethers

The reaction of tertiary amines with alkyl halides give quarternary ammonium salts [i]. In contrast, heating 2-(pentafluorophenoxy)ethyl-N,N-diethylamine (I) with decyl bromide (II), 2-(pentafluorophenoxy)ethyl bromide (III) or 2-(pentafluorophenoxy)ethyl iodide (IV) leads to an unusual transformation giving piperazinium dibromide (V) or diiodide (VI) along with the decyl ether of pentafluorophenol (VII) of the bispentafluorophenyl ether of ethyleneglycol (VIII) C2H5 C2tt 5 O1~ " @ I<