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PubMed2006

Amine mediated proton transfer reaction and C-Cl bond activation of solvent chloroform by a trinuclear copper(II) complex of a glucopyranosylamine derived ligand.

An amine mediated C-Cl bond activation process of the solvent chloroform has been explored by a coordinatively labile trinuclear Cu(II) complex, [Cu3(L1)2(MeOH)(H2O)] (1), derived from N-(3-tert-butyl-2-hydroxybenzylidene)-4,6-O-ethylidene--D-glucopyranosylamine (H3L1). The effect of activation is extremely high with methylamine, resulting in the formation of [Cu(MeNH2)5]Cl2 (2) and [Cu(L2)2] (3; HL2 = 2-tert-butyl-6-[(methylimino)methyl]phenol), however, under identical conditions it is moderate with ethylamine resulting in the isolation of crystals of the intermediate amine bound trinuclear copper(II) complex, [Cu3(L1)2(EtNH2)2(MeOH)2] (5), which was further converted into the mononuclear complex, [Cu(HL1)(EtNH2)] (6), in a novel crystal-to-crystal transformation. The successive isolation of the ethylamine-bound tri- and mononuclear complexes, 5 and 6, supported the occurrence of proton transfer reactions, which might be a key step in C-Cl bond activation. The primary and secondary amines, 2-aminomethylpyridine, N,N-dimethylethylenediamine, and 1,4,7-triazacyclononane, also having chelating features further enhance the rate of activation. No activation has been noted in the case of triethylamine and N,N,N,N-tetramethylethylenediamine. Formation of a carbene-trapped compound, 2,6-xylyl isocyanide, was confirmed in the reaction of complex 1 with 1,4,7-triazacyclononane and 2,6-xylidine in CHCl3, suggesting that the C-Cl bond cleavage led to the generation of dichlorocarbene. In addition, the mononuclear complex 6 has been transformed into a homotrinuclear complex [Cu3(L1)2(MeOH)2] by treatment with Cu(II) ions in MeOH/CHCl3, suggesting the possibility that the former could be regarded as a suitable metalloligand for heterotrimetallic complex synthesis.

Amines↗
PubMed1985

Histamine receptors on leukocytes: the binding of histamine serum albumin conjugates is non-specific.

It is commonly held that certain leukocyte sub-populations adhere selectively to histamine-serum albumin conjugates. A large number of soluble histamine, ethylamine and dimethylaminopropylamine conjugates were synthesised and labelled with fluorescein isothiocyanate (FITC). Although a number of conjugates bound to mononuclear cells and granulocytes our data showed this binding to be non-specific. The binding of histamine conjugates to leukocytes was not inhibited by preincubation of cells with free histamine at concentrations of up to 10(-1) M nor was it pH sensitive. In addition, conjugates of ethylamine and dimethylaminopropylamine showed a similar binding pattern to that of histamine conjugates. We suggest that the observed binding may be due to modifications to the net charge of the carrier protein molecule.

Carrier Proteins↗
PubMed2003

A photoactivated diazopyruvoyl cross-linking agent for bonding tissue containing type-I collagen.

On the basis of the earlier examples of diazopyruvoyl (DAP) groups reported by Lawton for covalent binding and cross-linking of proteins and oligopeptides and our recent demonstration that a coumaryl diazopyruvamide was used to label Type-I collagen, we have extended our investigations to the synthesis and cross-linking capabilities of a bis-DAP polyethylene glycol to cross-link Type-I collagen. The new photoactivated cross-linking agent, N,N'-bis(3-diazopyruvoyl)-2,2'-(ethylenedioxy)bis(ethylamine) (DPD, 2), has been designed and synthesized specifically to "weld" collagenous tissues by cross-linking Type-I collagen. A working model for the photochemical welding studies of collagenous tissues was developed using gelatin strips (gel strips) composed of denatured Type-I collagen. Gel strips are transparent to near-UV and visible light, uniform in thickness, and have reproducible composition. Furthermore, the availability of nucleophilic amine sites in gel strips was demonstrated by reaction with o-phthalaldehyde, producing a fluorescent derivative of the protein. Gel strips were coated with a solution of DPD in chloroform 7 irradiated at 320-390 nm, and the resulting bonded gel strips were tested for the strength of the weld. The welds were generally brittle and had average tensile strengths that exceeded 100 N/cm2. Welds were not formed in the absence of light or DPD. Scanning electron microscopy studies revealed a pockmarked surface from severed welds. Welds of rabbit Achilles tendon were also obtained using the tethered diazopyruvamide. These welds were much weaker, having an average tensile strength of 11.95 N/cm2 for DPD-2,2'-ethylenedioxy(bis)ethylamine comonomers in the cross-linking reaction. In both studies the welds obtained by this method were significantly stronger than the controls.

Achilles Tendon↗
PubMed1983

Measurement of the electrochemical proton gradient in submitochondrial particles.

The pH gradient and membrane potential of submitochondrial particles from bovine heart were estimated by the uptake of [14C]ethylamine and [36Cl]perchlorate, using filtration through a glass fiber prefilter and Millipore filter without washing to separate the vesicles from the medium. An external volume probe of [3H] sucrose was also used. Internal volume of the vesicles was measured by the extent of uptake of glucose, which equilibrates slowly across the membrane. The electrochemical potential gradient of H+ (delta micro H+) calculated from uptake of ethylamine and perchlorate, assuming the ions taken up were free in solution inside the vesicles, was 23 to 24 kJ/mol of H+ (240-250 mV) during respiration in the absence of ATP. The ratio of the free energy of ATP synthesis (delta GATP) to delta micro H+ was 2.2 to 2.3 during oxidative phosphorylation and only slightly higher during ATP hydrolysis indicating that the H+-translocating ATPase is close to equilibrium under both conditions. The nonintegral ratio suggests there is a systematic error in the measurement of delta micro H+. The value of delta micro H+ calculated from ion uptake could be too high if some of the ions taken up are bound to the membrane or concentrated into the electric double layer at the inner membrane-water interface. The effects of vesicle volume (varied osmotically) and permeant ions (which affect internal ionic strength and pH) on the ratio of delta GATP to delta micro H+ suggested that ion association with the membrane in fact caused significant overestimation of delta micro H+. Association of ethylammonium and perchlorate ions with unenergized submitochondrial particles was measured by centrifugation, in the presence of a high concentration of impermeant salt to minimize association with the external surface. The results were used to estimate the extent of binding during the ion uptake assays, and delta micro H+ was recalculated taking this binding into account. The resulting values were between 19 and 20 kJ/mol of H+ (197-207 mV) during respiration in the absence of ADP, and the ratio of delta GATP to delta micro H+ was about 3 during oxidative phosphorylation.

Ammonia↗
PubMedDate not supplied

Gas chromatographic--mass spectrometric determination of phenylacetic acid in human blood.

Phenyl acetic acid, a metabolite of 2-phenyl ethylamine, acts as a neuromodulator in the nigrostriatal dopaminergic pathway stimulating the release of dopamine. The evaluation of phenyl acetic acid concentration in the biological fluid reflects phenyl ethylamine levels thus allowing the assessment of the modulatory role of this endogenous substance. Changes in biological fluids levels of 2-phenylethylamine and/or in its metabolite have been reported in affective disorders, such as depression and schizophrenia. Recently, the occurrence of the "attention deficit hyperactivity syndrome" has been frequently reported in childhood population and involvement of dopaminergic dysfunction in this disease has been suspected. A fast, reliable and reproducible method for the determination of phenyl acetic acid in human blood, is therefore needed in order to have a screening tool for monitoring both healthy childhood population and suspected "attention deficit hyperactivity syndrome" patients. The gas chromatographic-mass spectrometric method here described makes use of a deuterated internal standard in order to overcome problems related to the lack of reproducibility often encountered when a derivatization step is performed.

Antimetabolites, Antineoplastic↗
PubMed2005

Responses of the silkworm tyramine receptor to 2-phenylethylamines and 5-phenyloxazoles.

Tyramine (TA), a biogenic amine, attenuates intracellular cAMP production by acting on its receptor in insects. Several non-biogenic amines were examined for their actions on native and heterologously expressed silkworm TA receptors. 5-(4-Hydroxyphenyl)oxazole, which showed an attenuating effect on cAMP production in silkworm-head membranes, did not attenuate forskolin-stimulated cAMP production in HEK-293 cells expressing the silkworm TA receptor, although the compound bound to the cloned receptor. 2-Phenylethylamines (2-PEAs), which showed positive and negative effects on cAMP production in silkworm-head membranes, inhibited [3H]TA binding to the cloned TA receptor. 2-Chloro-2-(4-chlorophenyl)ethylamine was the most potent inhibitor of [3H]TA binding among the 2-PEAs tested, with an IC50 of 30.4 nM. This compound acted as an antagonist and abolished TA-attenuation of forskolin-stimulated cAMP production in the cloned TA receptor. The discrepancy in the effects of the non-biogenic amines on the native and cloned TA receptors remains to be further examined. A newly synthesized 2-PEA, 2-chloro-2-(4-hydroxyphenyl)ethylamine, attenuated forskolin-stimulated cAMP production in the cloned TA receptor, indicating that the para-hydroxy group is important for the agonist action.

Animals↗
PubMed1977

Sulfur-containing derivatives of amphetamine: thioureas, methanesulfonamides, and trifluoromethanesulfonamides.

N-Methylthiourea, methanesulfonamide, and trifluoromethanesulfonamide derivatives of amphetamine, 4-nitroamphetamine, and 4-aminoamphetamine were synthesized. The N-methylthiourea derivative of amphetamine, as well as the triethylammonium salt of the dithiocarbamate, produced significant depressor effects in normotensive dogs. N,N'-Bis(methanesulfonyl)-1-methyl-2-(4-aminophenyl)ethylamine and N-trifluoromethanesulofonyl-1-methyl-2-phenylethylamine, but not N-methanesulfonyl-1-methyl-2-phenylethylamine and N-trifluoroacetyl-1-methyl-2-(4-trifluoromethanesulfonamido-phenyl))ethylamine, showed significant antiobesity effects in rats.

Amphetamines↗
PubMed1996

Synthesis and Behavior at the Air-Water Interface of Fluorinated Nonionic Surfactants Containing Two Methylated Polyoxyethylene Moieties.

The nonionic surfactants of the type polyoxyethylated monomethylated and containing a fluorinated tail were synthesized from 2-(F-alkyl)ethylamines. These compounds have two polyethoxylated tails with a perfectly defined number of oxyethylene motifs. Compared with their bipodal homologs within the F-alkylated series, these new structures were easily obtained from commercial raw materials which are the 2-(F-alkyl)ethyliodides. The evaluation of their behavior at the air-water interface has been studied from measurements of surface tension versus variation of concentration. This clearly shows the variation of the critical micelle concentration (c.m.c.) from 1.0.10(-5) to 2.5.10(-3) mol.liter(-1) and of the surface area per surfactant molecule versus studied structure. The N,N-dipolyethoxylene methoxyether of 2-(F-alkyl)ethylamines so realized exhibit noteworthy properties as nonionic fluorinated surfactants.

Journal Article↗
PubMed1998

Do parasympatholytic effects of long-acting beta 2-sympathomimetics contribute to their relaxant effects in airway smooth muscle cells?

To address the hypothesis of whether functional antagonistic effects of long-acting beta 2-sympathomimetics (formoterol and salmeterol) might be supported by direct antagonistic effects on muscarinic acetylcholine receptors (mAChR), we performed radioligand binding experiments with 3H-quinuclidinyl-benzilate in membranes of airway smooth muscle cells (calf tracheal myocytes). beta 2-Sympathomimetics (short- and long-acting) were compared to catechol-ethanolamines and catechol-ethylamines. Tracheal myocytes were characterized by a high density of mAChR 1017 +/- 17 fmol/mg, which exceeds that of beta 2-adrenoceptors 20-fold. The affinities of drugs were determined by competition binding. Dissociation constants ¿pKD-values) of formoterol (5.04 +/- 0.05) and salmeterol (5.24 +/- 0.04) matched that of ACh (5.37 +/- 0.03) and were significantly higher than that of the mAChR-agonist carbachol (4.65 +/- 0.03). pKD-values of mAChR-agonists were strictly dependent on GTP-concentration (> 50-fold difference between high- and low-affinity states), in contrast to those of formoterol, thereby characterizing formoterol as an mAChR-antagonist. A 10-fold lower affinity of the related compound fenoterol (3.94 +/- 0.02) hinted at the formyl-amino moiety of formoterol as a structural determinant of high-affinity whereas a 100-fold lower affinity of salbutamol as compared to salmeterol suggested the aliphatic side chain was a structural determinant of high affinity. The high affinity of dobutamine (4.96 +/- 0.02) and dopexamine (6.20 +/- 0.02) provided evidence that high affinity can be found not only for catechol-ethanolamines with long side chains but also for catechol-ethylamines. The question of whether high local concentrations after inhalation of long-acting beta 2-sympathomimetics could contribute to their therapeutical effects by antagonism with ACh on mAChR remains to be answered.

Adrenergic beta-Agonists↗
PubMed1994

N-methyl-D-aspartate (NMDA)-stimulated noradrenaline (NA) release in rat brain cortex is modulated by presynaptic H3-receptors.

In superfused rat brain cortex slices and synaptosomes preincubated with [3H]noradrenaline the effect of agonists or antagonists at presynaptic H3 receptors on NMDA-evoked [3H]noradrenaline release was investigated. In experiments on slices, histamine and the preferential H3 receptor agonist R-(-)-alpha-methylhistamine inhibited NMDA-evoked tritium overflow (IC20 values 0.27 mumol/l or 0.032 mumol/l, respectively); S-(+)-alpha-methylhistamine (up to 10 mumol/l) as well as the selective H1 receptor agonist (2-(2-thiazolyl)ethylamine and the selective H2 receptor agonist dimaprit (each up to 10 mumol/l) were ineffective. The H3 receptor antagonist thioperamide abolished the inhibitory effect of histamine whereas the preferential H1 receptor antagonist dimetindene and the preferential H2 receptor antagonist ranitidine were ineffective. In experiments on synaptosomes, histamine and R-(-)-alpha-methylhistamine inhibited NMDA-evoked tritium overflow, whereas 2-(2-thiazolyl)ethylamine or dimaprit had no effect. The inhibitory effect of histamine was abolished by thioperamide. When tritium overflow was stimulated by NMDA in the presence of omega-conotoxin GVIA (which by itself decreased the response to NMDA by about 55%), R-(-)-alpha-methylhistamine did not inhibit NMDA-evoked overflow. It is concluded that NMDA-evoked noradrenaline release in the cerebral cortex can be modulated by inhibitory H3 receptors. NMDA receptors and H3 receptors are both located presynaptically and may interact at the same noradrenergic varicosity. An unimpaired function of the N-type voltage-sensitive calcium channel probably is a prerequisite for the inhibition of NMDA-evoked noradrenaline release by H3 receptor stimulation.

Animals↗
PubMed1981

Utilization of amines by yeasts.

461 Strains of the yeast collection of the Centraalbureau voor Schimmelcultures (CBS) were screened for their ability to utilize 9 different amines as a sole carbon and energy source and/or as nitrogen source. A miniaturized technique with microtiter plates was used. None of the primary and methylated amines tested (i.e. methylamine, dimethylamine, trimethylamine, tetramethylammonium chloride, choline, ethylamine, propylamine, butylamine and benzylamine) were utilized as a carbon and energy source, although the majority of yeasts (86%) were able to utilize one or more of these compounds as a nitrogen source. The ability to utilize ethylamine and higher homologues occurred more frequently than the ability to utilize methylated amines. In almost all genera the utilization of primary and methylated amines was found, with utilization among yeasts and the inability of these organisms to utilize amines as a carbon and energy source is discussed.

Amines↗
PubMed1981

Neurochemical and behavioural profiles of five dopamine analogues.

The dopaminergic actions of five hydroxylated dopamine analogues have been examined for: i) Ability to induce stereotypy, ii) Effects upon dopamine metabolism, iii) Ability to antagonise the rise in striatal dopamine caused by gammabutyrolactone. With the exception of the resorcinol derivative 2-(3,5-dihydroxyphenyl)-N,N-dipropylethylamine, all of the compounds tested exhibited dopamine-like actions, and similarities were found in the induction of stereotypy and in the reduction of dopamine metabolism. For example, 2-(3-hydroxyphenyl)-N,N-dipropylethylamine had a short duration of action as far as reducing dopamine metabolism and inducing stereotypy were concerned. On the other hand, 2-(3-hydroxyphenyl)-N-n-propyl-N-phenyl-ethyl-ethylamine (e) and also 5-hydroxy-2-(N-n-propyl-N-phenylethyl)-aminotetralin had a long duration of agonist-like effects upon both parameters, the aminotetralin derivative being the more potent of the two. Thus, in going from the simple dopamine-like structure to the aminotetralin compound there has been an increase in dopamine agonist-like activity. The differences in dopamine agonist potency of the drugs used are discussed in relation to the structure of these compounds, and are compared with the potencies or related compounds. Also, the potencies of the compounds under investigation upon presynaptic dopamine receptors (using the gammabutyrolactone model as a test system) were investigated, and the ester, 2-(3-benzoyloxyphenyl)-N-n-propyl-N-phenylethyl-ethylamine was the most potent. This ester, which is probably converted to (e) in the brain, also had a long duration of action in the stereotypy and dopamine metabolism tests. The results suggest that certain of the compounds might be useful leads for the design of dopamine agonists of possible clinical use.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1981

Additional data on the function of hypothalamic histamine.

In a preliminary study, the stimulatory effect of histamine on an adenylate cyclase system in a solubilized cell-free preparation of the rat hypothalamus was established. The effect was dose dependent, and the histamine concentration required for half-maximal activation (Ka) was determined at 0.1 muM. At a 10-fold higher concentration, both chloropyramine, the classical histamine H1 antagonist, and metiamide, the selective H2-receptor blocker, partially blocked this action. Experiments carried out in hypothalamic slices showed a stimulatory effect of both the H1-agonist, 2-(2-pyridyl)-ethylamine, and the H2-antagonist, dimaprit, on adenylate cyclase in the range of histamine action. These effects could be reversed completely by the H1-antagonist, mepyramine, and the H2-receptor blocker cimetidine. In an additional study, histamine, histamine agonists and antagonists were tested on the spontaneous and the potassium-activated outflow of 3H-noradrenaline from rat hypothalamic slices. Histamine did not modify this outflow significantly, whereas the H1-agonist 2-(2-pyridyl)-ethylamine, produced a marked, dose-related increase in both the spontaneous and the potassium-stimulated release of noradrenaline. The H2-receptor blocker, cimetidine, also exerted a moderate but statistically significant stimulatory effect in this system. In combination studies, the noradrenaline-releasing action of these compounds could not he reversed by the selectively acting histaminic or antihistaminic agents, showing that this effect does not relate to the histaminic or antihistaminic property of the compound. It is becoming clear that histamine exerts a direct stimulatory effect on hypothalamic adenylate cyclase. The noradrenaline-releasing potency of some histaminic and antihistaminic agents showed that these compounds might modify the clear histamine effects through the release of other transmitter amines.

Adenylyl Cyclases↗
PubMed2005

Microbial synthesis of chiral amines by (R)-specific transamination with Arthrobacter sp. KNK168.

Arthrobacter sp. KNK168 shows (R)-enantioselective transaminase [(R)-transaminase] activity, which converts prochiral ketones into the corresponding chiral (R)-amines in the presence of an amino donor. The cultural conditions and reaction conditions for asymmetric synthesis of chiral amines with this microorganism were examined. The transaminase was inducible, and its production was enhanced by the addition of sec-butylamine and 3-amino-2,2-dimethylbutane to the culture medium. (R)-1-Phenylethylamine was a good amino donor for amination of 3,4-dimethoxyphenylacetone with Arthrobacter sp. KNK168. Under the optimum conditions, 126 mM (R)-3,4-dimethoxyamphetamine (DMA) [>99% enantiomeric excess (ee)] was synthesized from 154 mM 3,4-dimethoxyphenylacetone and 154 mM (R)-1-phenylethylamine through the whole cell reaction with an 82% conversion yield. (R)-Enantiomers of other amines, such as (R)-4-methoxyamphetamine, (R)-1-(3-hydroxyphenyl)ethylamine and (R)-1-(3-hydroxyphenyl)ethylamine, were also synthesized from the corresponding carbonyl compounds through asymmetric amination with Arthrobacter sp. KNK168.

Acetone↗
PubMed1982

Biphasic uptake of iron-transferrin complex by L1210 murine leukemia cells and rat reticulocytes.

The kinetics of the cellular uptake of iron-transferrin complex was studied in L1210 murine leukemia cells and rat reticulocytes using 125I-transferrin. Saturation of transferrin with iron was necessary for optimal uptake. Following the incubation of cells with the radiolabeled complex a biphasic pattern of uptake was observed. The initial phase was rapid and relatively temperature-independent and was not altered by ethylamine, an inhibitor of transglutaminase activity which is necessary for receptor-mediated endocytosis. This phase was considered to result from receptor-ligand interaction which could be reversed to a great degree by replacement with unlabeled transferrin. A plateau was then reached, indicating a saturation of receptors. After 30 min a second phase of uptake was indicated by the second rise in the curve. This phase was slow, relatively temperature-dependent and could be abolished by ethylamine. It was interpreted as evidence of internalization of the ligand. Analysis of the data from competition studies with unlabeled transferrin indicated that the first phase might itself comprise a reversible and an irreversible step with a ratio of 5 to 1.4 for bound transferrin. Thus, the cellular uptake of iron-transferrin complex may consist of a reversible ligand-receptor interaction. Conformational changes may render this interaction irreversible and the internalization of the ligand may then follow.

Animals↗
PubMed1989

Pathways and kinetics of aqueous decomposition and carbamoylating activity of new anticancer nitroimidazole-linked 2-chloroethylnitrosoureas.

The products of decomposition in anaerobic aqueous solution at pH 7.1 and 37 degrees were determined for two series of novel anticancer agents incorporating both nitroimidazole and 2-chloroethylnitrosourea moieties (NI-CENUs) and examples of which exhibit preferential hypoxic toxicity against HeLa-MR cells. The decomposition products identified were vinyl chloride, acetaldehyde, 2-chloroethanol, ethylene glycol and imidazole-bearing compounds of the type including oxazolidinone, ethylamine or urea moieties. Series A NI-CENUs, which contain a 2-hydroxypropyl unit, gave rise to the oxazolidinone intramolecularly compared with the series B agents which gave rise to the imidazole-ethylamine and ureas. The half-lives of the B series agents were comparable with those of 1,3-bis(2-chloroethyl)nitrosourea (BCNU), 2-cyclohexyl-1-(2-chloroethyl)-1-nitrosourea (CCNU) and streptozotocin. The carbamoylation activity of the series B agents was approximately ten times that of series A compounds. This latter property may be related to the greater potency of series B than series A NI-CENUs against Mer+ HeLa-S3 cells via inhibition of relevant repair enzymes.

Antineoplastic Agents↗
PubMed1981

Cyclic AMP increase in canine parotid gland mediated by histamine H2-receptors.

Histamine, 4-methylhistamine and dimaprit induced a dose-dependent increase in the cyclic AMP content of chopped canine parotid gland in the presence of 3-isobutyl-1-methylxanthine. Metiamide, but not mepyramine, inhibited the effect of these agonists dose-dependently. The cyclic AMP content was also increased by 2-(2-pyridyl)ethylamine. This effect was completely blocked by propranolol. These results indicate that the cyclic AMP response to histamine in canine parotid gland is mediated by H2-receptors. Mepyramine enhanced the effect of histamine. However, 2-(2-pyridyl)ethylamine had no significant inhibitory effect on the cyclic AMP response to 4-methylhistamine. A combination of aminoguanidine and quinacrine potentiated the effect of histamine, though no difference was observed in the histamine concentration of the media with or without these inhibitors when determined at the end of incubation. This suggests that there exist active histamine-metabolizing systems in canine parotid gland.

Animals↗