Quaternary Ammonium Derivatives Research Articles

Molecular basis for the polyamine-OmpF porin interactions: inhibitor and mutant studies

By testing the sensitivity of Escherichia coliOmpF porin to various natural and synthetic polyamines of different lengths, charge and other molecular characteristics, we were able to identify the molecular properties required for compounds to act as inhibitors of OmpF in the nanomolar range. Inhibitors require at least two amine groups to be effective. For diamines, the optimum length of the hydrocarbon spacer was found to be of eight to ten methylene groups. Triamine molecules based on a 12-carbon motif were found to be more effective that spermidine, an eight-carbon trivalent derivative. But differences in inhibition efficiencies were also found for trivalent compounds depending on the relative position of the internal secondary amine group with respect to the terminal groups. Finally, quaternary ammonium derivatives had no effect, suggesting that the nature of the terminal amine is important for the interaction. From these observations, we deduce that inhibition efficiency in the nanomolar range requires a 12-carbon chain triamine with terminal primary amine groups and replacement of the eighth methylene by a secondary amine. The need for this type of molecular architecture suggests that inhibition is governed by interactions between specific amine groups and protein residues, and that this is not simply due to the accumulation of charges into the pore. Together with previous observations from site-directed mutagenesis studies and inspection of the crystal structure of OmpF, these results allowed us to propose three residues (D113, D121 and Y294) as putative sites of interaction between the channel and spermine. Alanine substitution at each of these three residues resulted in a loss of inhibition by spermine, while mutations of only D113 and D121 affected inhibition by spermidine. Based on these observations, we suggest a model for the molecular determinants involved in the porin-polyamine interaction.

Anomalous phase behavior of water-soluble polyelectrolyte and oppositely charged surfactants

Aqueous mixtures of anionic surfactants with cationically substituted quaternary ammonium derivatives of hydroxyethylcellulose, JR and LR series, were investigated by several techniques. On adding sodium dodecyl sulfate (SDS) to a polyelectrolyte solution, phase separation with precipitation occurs in a co-operative way, and redissolution of precipitation is observed at the critical micelle concentration (CMC) of SDS. This is due to admicelle formation on the polyelectrolyte. The phase separation for the two-headed anionic surfactant systems is also seen, while the concentration where this takes place is near the CMC of the surfactant. This is remarkable in the case of the triethanolamine cocoyl glutamate (TCG)–JR 400 system, in which TCG has a CMC over 1 order of magnitude smaller CMC than that of SDS. Surface tension and the dynamic light scattering measurements show the existence of not only electrostatic interaction between the cationic polyelectrolyte and the two-headed anionic surfactant but also intraction between the adsorbed polymers. The scaling analysis of the precipitation line of the surfactant with polyelectrolyte concentration elucidates that one molecule of TCG can neutralize approximately two charges on JR 400.

Antimuscarinic, calcium channel blocker and tachykinin NK2 receptor antagonist actions of otilonium bromide in the circular muscle of guinea-pig colon.

We have analyzed, by the sucrose gap method, the action of otilonium bromide, a quaternary ammonium derivative in use for the symptomatic therapy of irritable bowel syndrome, on the electrical and mechanical responses initiated by different stimuli in the circular muscle of the guinea-pig proximal colon. Otilonium bromide produced a concentration-dependent inhibition of membrane depolarization (IC50 4.1 microM), action potentials (APs) and contraction (IC50 3.7 microM) produced by the muscarinic receptor agonist, methacholine. It also produced a concentration-dependent inhibition of APs and accompanying contraction (IC50 31 microM) produced by KCl (30 mM), and had a biphasic effect on the cholinergic excitatory junction potential (e.j.p.) produced by single pulse electrical field stimulation: at low concentrations (0.1-0.3 microM) otilonium bromide enhanced the e.j.p. and, at higher concentrations (IC50 22 microM and 16 microM toward depolarization and contraction), produced a concentration-dependent inhibition. Otilonium bromide eliminated the APs superimposed on the depolarization induced by the tachykinin NK1 receptor agonist, [Sar9]substance P-sulphone and suppressed the corresponding contraction (IC50 43 microM) but had little effect on the sustained membrane depolarization induced by this agonist. On the other hand, otilonium bromide produced a similar inhibitory effect on both membrane depolarization and contraction (IC50 38 microM and 45 microM, respectively) induced by the tachykinin NK2 receptor agonist [betaAla8]neurokinin A (4-10). When tested in the presence of nifedipine (1 microM), otilonium bromide had no effect on the membrane depolarization induced by [Sar9]substance P-sulphone but inhibited in a concentration-dependent manner the depolarization induced by [betaAla8]neurokinin A (4-10) (IC50 41 microM). In contrast, the blocker of receptor-operated cation channels, SKF 96365, inhibited with similar potency the depolarization induced by both [Sar9]substance P-sulphone and [betaAla8]neurokinin A (4-10) (IC50 60 microM and 54 microM, respectively). In radioligand binding experiments otilonium bromide produced a concentration-dependent inhibition of the binding of both an agonist ([125I]neurokinin A, Ki 7.2 microM) and an antagonist ([3H]SR 48968, Ki 2.2 microM) to membranes of Chinese hamster ovary cells transfected with the human tachykinin NK2 receptor. In conclusion, the present findings demonstrate that, in the microM range of concentrations, otilonium bromide acts as a muscarinic and tachykinin NK2 receptor antagonist and as a calcium channel blocker. The latter property is likely to account for its ability to suppress contraction initiated by the tachykinin NK1 receptor agonist. Therefore multiple mechanisms of action account for the ability of otilonium bromide to reduce stimulated motility of intestinal smooth muscle.

Synthesis of a Quaternary Ammonium Derivative of Chitosan and Its Application to a Cotton Antimicrobial Finish

A quaternary ammonium derivative of chitosan, N-(2-hydroxy)propyl-3-trimethy lammonium chitosan chloride (HTCC), is synthesized as an antimicrobial finish for cotton using a reaction of glycidyltrimethylammonium chloride (GTMAC) and chitosan. Results indicate that the degree of substitution (DS) in HTCC calculated by chloride content is a function of the reaction temperature and mole ratio of GTMAC and NH2 in chitosan. Excess amounts of GTMAC are generally needed to obtain a water-soluble fraction of HTCC. A minimum DS of 0.6 is needed to yield water-soluble HTCC. Syn thesized HTCC is analyzed by FTIR, H 1-NMR, TGA, and x-ray diffraction techniques. At very low concentrations, such as 0.025% owb, HTCC shows superior antimicrobial ac tivity indicated by an almost 100% bacterial reduction, whereas 1 % owb chitosan shows only 30% bacterial reduction. Since HTCC is soluble in water, we have examined several methods to increase the laundering durability of cotton treated with HTCC. Among them, application of a nonionic binder considerably improves the laundering durability of HTCC-treated cotton.

ChemInform Abstract: 2‐Nitrobenzyl Quaternary Ammonium Derivatives Photoreleasing Norbutyrylcholine in the Microsecond Time Range.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

2-Nitrobenzyl Quaternary Ammonium Derivatives Photoreleasing Nor-butyrylcholine in the Microsecond Time Range

2-Nitrobenzyl derivatives of nor-butyrylcholine (N,N-dimenthylaminoethyl butyrate) were synthesized and characterized as photolabile inhibitors of butyrylcholinesterase, displaying the required photofragmentation kinetics for rapid release of the enzyme substrate, nor-butyrylcholine. © 1997 Elsevier Science Ltd.

Thermodynamic Studies on the Cyclodextrin Complexation of Aromatic and Aliphatic Guests in Water and Water−Urea Mixtures. Experimental Evidence for the Interaction of Urea with Arene Surfaces

The thermodynamic functions that describe the complexation of a series of four carboxylic acid guests and two related quaternary ammonium derivatives with β-cyclodextrin were measured using flow calorimetry at 298 K in aqueous media in the presence and in the absence of large concentrations of urea. The relative differences of the thermodynamic parameters of complexation revealed the existence of specific interactions between urea and the aromatic surfaces of some of the nonpolar guests. As expected, the relative changes in the complex stability constants upon addition of urea have been found to depend on the balance of opposing enthalpic and entropic contributions. The interpretation as well as the magnitude of the interaction between urea and aromatic surfaces are in line with previous experimental and computational studies. The experimental evidence presented in this work provides insight into the mechanism by which large amounts of urea denature globular proteins in aqueous media.

1,5-benzothiazepine binding domain is located on the extracellular side of the cardiac L-type Ca2+ channel.

To determine whether 1,5-benzothiazepine Ca2+ channel blocker approaches its binding domain within the cardiac L-type Ca2+ channel from inside or outside of the membrane, we tested the effects of a novel potent 1,5-benzothiazepine derivative (DTZ323) and its quaternary ammonium derivative (DTZ417) on guinea pig ventricular myocytes by using the whole-cell patch-clamp technique. The extracellular application of DTZ417 suppressed the L-type Ca2+ channel currents (I[Ca(L)]) with an IC50 value of 1.2 +/- 0.02 microM, which was close to the IC50 value of diltiazem (0.63 +/- 0.01 microM). The suppression of I[Ca(L)] by DTZ417 was voltage and use dependent but lacked tonic block, which allowed us to investigate the onset of the effect on I[Ca(L)] by changing the holding potential (HP) from -90 to -50 mV in the presence of DTZ417. DTZ417 did not have significant effects on I[Ca(L)] at an HP of -90 mV. At -50 mV, DTZ417 (50 microM) applied from the extracellular side completely suppressed I[Ca(L)], whereas it had no effect from the intracellular side. DTZ323 (1 microM) also inhibited I[Ca(L)] only from the extracellular side, without any effects by the intracellular application of < or = 10 microM. However, a quaternary phenylalkylamine derivative, D890 (0.1 mM), acted only from the intracellular side. These results suggest that in contrast to the phenylalkylamine binding site, in cardiac myocytes the 1,5-benzothiazepine binding site is accessible from the extracellular side of the L-type Ca2+ channel.

Dihydrotestosterone with an Ammonium Centre in the Position 16β

In an alternative synthesis of 17β-hydroxy-16β-(piperidin-1-yl)-5α-androstan-3-one (4), neighbouring group participation between a 17β-carbonyloxy group and the 16β-amino group was used and a high yield partial hydrolysis of 3β,17β-diacetoxy-16β-(piperidin-1-yl)-5α-androstane (11) was developed. Interference of the neighbouring group participation was also apparent in another 17β-acetoxy derivative - in oxidation of compound 12 to 13. Compound 4 was converted into water-soluble derivatives, i.e. quaternary ammonium derivatives 17 to 20.

Guest/Host Interactions in High Silica Zeolite Synthesis: [5.2.1.02.6]Tricyclodecanes as Template Molecule

Zeolite synthesis results for the use of a family of related quaternary ammonium derivatives of tricyclodecane hydrocarbons as structure-directing agents are described. The work continues our inter...

Quaternary ammonium derivative of lidocaine as a long-acting local anesthetic.

Use of long-acting local anesthetics that elicit complete neural blockade for more than 3 h often is desirable in pain management. Unfortunately, clinically available local anesthetics are in general not suitable for prolonged analgesia. This report describes the organic synthesis and functional testing of a lidocaine derivative that appears to fulfill the criteria of long-acting local anesthetics. A lidocaine derivative, N-beta-phenylethyl lidocaine quaternary ammonium bromide, was synthesized, and its ability to inhibit Na+ currents in cultured rat neuronal GH3 cells was tested in vitro under whole-cell voltage clamp conditions. Neurologic evaluation of sciatic nerve block of sensory and motor functions in vivo was subsequently performed in rats. N-beta-phenylethyl lidocaine was found to be a potent Na+ channel blocker in vitro. It produced both tonic and use-dependent blocks of Na+ currents that exceeded lidocaine's effects by a factor of > 2 (P < 0.05). In vivo, N-beta-phenylethyl lidocaine elicited a prolonged and complete sciatic nerve block of the motor function and the withdrawal response to noxious pinch that was 3.6- and 9.3-fold longer than that of lidocaine (P < 0.001), respectively. In an attempt to elicit prolonged local anesthesia, a quaternary ammonium derivative of lidocaine containing a permanent charge and an additional hydrophobic component was synthesized. Complete sciatic neural blockade of more than 3 h was achieved with this derivative. Of note, sensory blockade was prolonged to a greater extent than motor blockade. The approach used in this study may prove useful for developing new drugs applicable in pain management.

Scanning electron microscopic evaluation of ultrasonic debridement comparing sodium hypochlorite and Bardac-22

This study compared in vitro the debridement ability of a 3% sodium hypochlorite with a new quaternary ammonium derivative, a 0.5% Bardac-22 solution, in the apical third of freshly extracted teeth with straight root canals. Root canals were instrumented sequentially from size 10 to size 35 using alternatively hand and ultrasonic files. When the hand file was loose in the canal, the ultrasonic instrument of the same size was operated at working length for 30 s, delivering 15 ml of the selected solution. Both solutions were able to flush out pulpal debris from the canal space. At the apical end of the preparation, sodium hypochlorite left a thicker smear layer than Bardac-22 did. The quaternary ammonium derivative easily dissolved the inorganic portion of the smear layer, but did not dissolve proteins as well as sodium hypochlorite.

Trospium chloride versus oxybutynin: a randomized, double‐blind, multicentre trial in the treatment of detrusor hyper‐reflexia

To compare trospium chloride (TCl), a quaternary ammonium derivative with atropine-like effects and predominantly antispasmodic activity, with oxybutynin (Oxy) in terms of efficacy and adverse effects. In a randomized, double-blind, multicentre trial, 95 patients with spinal cord injuries and detrusor hyper-reflexia were studied. Treatment consisted of three doses per day over a 2 week period, with either Oxy (5 mg three times daily) or with TCl (20 mg twice daily) with an additional placebo at midday. The results were evaluated with regard to changes in objective (urodynamic) data and subjective symptoms as well as the incidence/severity of adverse effects. With both drugs there was a significant increase in maximum bladder capacity, a significant decrease in maximum voiding detrusor pressure and a significant increase in compliance and residual urine; there were no statistically significant differences between the treatment groups. The percentage of patients who reported severe dryness of the mouth was considerably lower (4%) in those receiving TCl 2 x 20 mg/day than in those receiving Oxy (23%) 3 x 5 mg/day. Withdrawal from treatment was also less frequent in those receiving TCl (6%) than in those receiving Oxy (16%). Trospium chloride and oxybutynin, judged in terms of objective urodynamic parameters, are of substantially equal value as parasympathetic antagonists. However, assessment of tolerance in terms of adverse drug effects showed that TCl had certain advantages.

Depolarizing neuromuscular blocking action of coryneine derived from aconite root in isolated mouse phrenic nerve-diaphragm muscles.

The mode of the neuromuscular blocking action of coryneine (a quaternary ammonium derivative of dopamine) derived from aconite root was investigated in isolated phrenic nerve-diaphragm muscles and denervated diaphragm muscles of mice. Coryneine (20-150 microM) blocked the nerve-evoked twitch response without affecting the contraction evoked by electrical stimulation of the muscle. The blocking effect was reversed by neostigmine, a cholinesterase inhibitor. The electrical charge-response curve on depolarization produced by iontophoretically applied acetylcholine (ACh) at the endplate regions in normal muscles was shifted to the right on decreasing the maximal response by 40 microM coryneine. The double-reciprocal plot revealed that coryneine reduced the apparent affinity of ACh for its receptor on decreasing the maximal response. Coryneine (20 microM-2mM) itself depolarized the endplate membrane and this effect was reversibly suppressed by 1 and 5 microM pancuronium. Coryneine 30 microM-10mM) produced contractions of denervated muscles in a concentration-dependent manner and the effects were reduced by 70nM pancuronium. These results indicate that coryneine is a depolarizing agent and a mixed-type competitive and noncompetitive neuromuscular blocker.

Biological Recognition of Enantiomeric Silanes: Syntheses and Antimuscarinic Properties of Optically Active (2-Aminoethyl)cyclohexyl(hydroxymethyl)phenylsilanes and Related Quaternary Ammonium Derivatives

Biological Recognition of Enantiomeric Silanes: Syntheses and Antimuscarinic Properties of Optically Active (2-Aminoethyl)cyclohexyl(hydroxymethyl)phenylsilanes and Related Quaternary Ammonium Derivatives

Differential inhibition of neuronal calcium entry and [3H]-D-aspartate release by the quaternary derivatives of verapamil and emopamil.

1. Verapamil and emopamil are structurally related phenylalkylamine calcium channel/5-HT2 receptor antagonists that differ in their anti-ischaemic properties in experimental studies. The quaternary ammonium derivatives of these compounds were prepared and tested in assays of neuronal voltage-sensitive calcium channel (VSCC) function to determine whether the compounds act at intra- or extracellular sites. 2. The compounds were tested in K(+)-evoked: (1) rat brain synaptosomal 45Ca2+ influx, (2) release of [3H]-D-aspartate from rat hippocampal brain slices and (3) increase of intracellular calcium in rat cortical neurones in primary culture. 3. Verapamil, emopamil and the emopamil quaternary derivative caused concentration-dependent and comparable (IC50 values approximately 30 microM) inhibition of synaptosomal 45Ca2+ influx and [3H]-D-aspartate release. The verapamil quaternary derivative was considerably less active in these assays (IC50 > 300 microM). 4. The evoked increase of intracellular calcium in cortical neurones was inhibited with the following rank order of potency (IC50 value, microM): emopamil (3.6) > verapamil (17) > emopamil quaternary derivative (38) > verapamil quaternary derivative (200). 5. The results suggest that verapamil and emopamil inhibit nerve terminal VSCC function (synaptosomal 45Ca2+ influx and [3H]-D-aspartate release) by acting at distinct intracellular and extracellular sites, respectively. Verapamil and emopamil may inhibit cell body VSCC function (evoked increase of intracellular calcium in neocortical neurones) by acting at both intracellular and extracellular sites. 6. The different 'sidedness' of action of emopamil and verapamil on nerve terminal VSCC function and/or the preferential inhibition of cell body VSCC function by emopamil may at least partially explain the relatively greater neuroprotective efficacy of emopamil in experimental models of ischaemia.

Gas Chromatographic Separation of Linear Hydrocarbons on Microporous Organo-Smectites

AbstractA series of organo-montmorillonites and organo-hectorites was prepared by complete ion-exchange from the pure sodium form of the parent smectites. The organic cations were tetramethylammonium, trimethylated quaternary ammonium derivatives of the lysine and of the ornithine methyl esters, quaternarized polyammonium cations, or tetraphenylphosphonium (TPP). These organo-smectites were used as packing material for gas chromatography columns. Mixtures of light hydrocarbons (methane to n-butane; “C1” to “C4”) could be separated. The degree of separation depends on the presence of micropores or of organophilic mesopores. The BET surface area, the micropore and mesopore volumes, as well as the size distribution of micropores and mesopores were measured for several systems. As a general trend, the retention times of the light hydrocarbons decrease with an increase of the micropore volume. In the case of TPP-montmorillonite, characterized by a large mesopore volume but for which no microporosity could be detected, separation of longer linear hydrocarbons (n-pentane to n-octane) could also be achieved.

Binding and functional properties of hexocyclium and sila‐hexocyclium derivatives to muscarinic receptor subtypes

1. We have compared the binding properties of several hexocyclium and sila-hexocyclium derivatives to muscarinic M1 receptors (in rat brain, human neuroblastoma (NB-OK 1) cells and calf superior cervical ganglia), rat heart M2 receptors, rat pancreas M3 receptors and M4 receptors in rat striatum, with their functional antimuscarinic properties in rabbit vas deferens (M1/M4-like), guinea-pig atria (M2), and guinea-pig ileum (M3) muscarinic receptors. 2. Sila-substitution (C/Si exchange) of hexocyclium (-->sila-hexocyclium) and demethyl-hexocyclium (-->demethyl-sila-hexocyclium) did not significantly affect their affinities for muscarinic receptors. By contrast, sila-substitution of o-methoxy-hexocyclium increased its affinity 2 to 3 fold for all the muscarinic receptor subtypes studied. 3. The p-fluoro- and p-chloro-derivatives of sila-hexocyclium had lower affinities than the parent compound at the four receptor subtypes, in binding and pharmacological studies. 4. In binding studies, o-methoxy-sila-hexocyclium (M1 = M4 > or = M3 > or = M2) had a much lower affinity than sila-hexocyclium for the four receptor subtypes, and discriminated the receptor subtypes more poorly than sila-hexocyclium (M1 = M3 > M4 > M2). This is in marked contrast with the very clear selectivity of o-methoxy-sila-hexocyclium for the prejunctional M1/M4-like heteroreceptors in rabbit vas deferens. 5. The tertiary amines demethyl-hexocyclium, demethyl-sila-hexocyclium and demethyl-o-methoxy-sila-hexocyclium had 10 to 30 fold lower affinities than the corresponding quaternary ammonium derivatives.

Enhanced gene delivery and mechanism studies with a novel series of cationic lipid formulations.

The application of cationic liposome reagents has advanced DNA and mRNA transfection research in vitro, and data are accumulating which show their utility for in vivo gene transfer. However, chemical structure-activity data leading to a better mechanistic understanding of their biological activity is still limited. Most of the cationic lipid reagents in use today for this application are formulated as liposomes containing two lipid species, a cationic amphiphile and a neutral phospholipid, typically dioleoylphosphatidylethanolamine (DOPE). The studies reported here examine the effects of some systematic chemical structural changes in both of these lipid components. Cationic and neutral phospholipids were formulated together as large multilamellar vesicles (MLV) or small sonicated unilamellar vesicles (SUV) in water, and each formulation was assayed quantitatively in 96-well microtiter plates under 64 different assay conditions using COS.7 cells and an RSV-beta-galactosidase expression plasmid. The cationic lipid molecules used for these studies were derived from a novel series of 2,3-dialkyloxypropyl quaternary ammonium compounds containing a hydroxyalkyl moiety on the quaternary amine. A homologous series of dioleylalkyl (C18:1) compounds containing increasing hydroxyalkyl chain lengths on the quaternary amine were synthesized, formulated with 50 mol % DOPE, and assayed for transfection activity. The order of efficacy was ethyl > propyl > butyl > pentyl > 2,3-dioleyloxypropyl-1-trimethyl ammonium bromide (DOTMA). DOTMA, which is commercially available under the trademark Lipofectin Reagent, lacks a hydroxyalkyl moiety on the quaternary amine. A homologous series of hydroxyethyl quaternary ammonium derivatives with different alkyl chain substitutions were synthesized, formulated with 50 mol % DOPE, and assayed in the transfection assay. The order of transfection efficacy was dimyristyl (di-C14:0) > dioleyl (di-C18:1) > dipalmityl (di-C16:0) > disteryl (di-C18:0). The addition of 100 microM chloroquine in the transfection experiment enhanced the activity of the dioleyl compound by 4-fold and decreased the activity of the dimyristyl compound by 70%. For each of the compounds and formulations examined in this report, large multilamellar vesicles (MLV; diameter 300-700 nm) were more active than small unilamellar vesicles (SUV; diameter 50-100 nm). The neutral phospholipid requirements for transfection activity in COS.7 cells with these cationic lipid molecules were examined.(ABSTRACT TRUNCATED AT 400 WORDS)

Simplification of high-energy collision spectra of peptides by amino-terminal derivatization.

Four-sector tandem mass spectrometry proves extremely useful for providing sequence information for peptides. The complexity of ion fragmentations, however, makes data interpretation difficult and time consuming. Attachment of a fixed positive charge to the peptide amino terminus forces production of only N-terminal fragment ions to yield simplified, predictable fragmentation. Reaction of a peptide at pH 6 with iodoacetic anhydride selectively modifies the N-terminus by exploiting the pK(a) differences between the alpha-amino group and any lysine side-chain epsilon-amino groups. The iodoacetyl peptide can react with many reagents to form a fixed positive charge. We find reaction with dimethyloctylamine forms a quaternary ammonium derivative with good surface activity properties and concomitant increased sensitivity. The high-energy CAD fragment ion spectra of the N-terminally derivatized peptides show predominantly a(n) and d(n) ions. The abundant d(n) ions permit ready distinction of leucine and isoleucine. Fewer fragment ions make data interpretation simpler and lead to more intense peaks since the ion intensity is spread among fewer peaks. The method is particularly useful for peptides which do not otherwise yield sufficient fragmentation to provide either the complete sequence or the locations of modified amino acids.