Science.gov

Sample records for aromatic amine p-anilinoaniline

  1. Suppression of autophagy enhances the cytotoxicity of the DNA-damaging aromatic amine p-anilinoaniline

    SciTech Connect

    Elliott, Althea; Reiners, John J.

    2008-10-15

    p-Anilinoaniline (pAA) is an aromatic amine that is widely used in hair dying applications. It is also a metabolite of metanil yellow, an azo dye that is commonly used as a food coloring agent. Concentrations of pAA between 10 and 25 {mu}M were cytostatic to cultures of the normal human mammary epithelia cell line MCF10A. Concentrations {>=} 50 {mu}M were cytotoxic. Cytostatic concentrations induced transient G{sub 1} and S cell cycle phase arrests; whereas cytotoxic concentrations induced protracted arrests. Cytotoxic concentrations of pAA caused DNA damage, as monitored by the alkaline single-cell gel electrophoresis (Comet) assay, and morphological changes consistent with cells undergoing apoptosis and/or autophagy. Enzymatic and western blot analyses, and binding analyses of fluorescent labeled VAD-FMK, suggested that caspase family members were activated by pAA. Western blot analyses documented the conversion of LC3-I to LC3-II, a post-translational modification involved in the development of the autophagosome. Suppression of autophagosome formation, via knockdown of ATG7 with shRNA, prevented pAA-induced vacuolization, enhanced the activation of pro-caspase-3, and increased susceptibility of ATG7-deficient cells to the cytostatic and cytotoxic activities of markedly lower concentrations of pAA. Cells stably transfected with a nonsense shRNA behaved like parental MCF10A cells. Collectively, these data suggest that MCF10A cultures undergo autophagy as a pro-survival response to concentrations of pAA sufficient to induce DNA damage.

  2. Bacterial degradation of monocyclic aromatic amines

    PubMed Central

    Arora, Pankaj K.

    2015-01-01

    Aromatic amines are an important group of industrial chemicals, which are widely used for manufacturing of dyes, pesticides, drugs, pigments, and other industrial products. These compounds have been considered highly toxic to human beings due to their carcinogenic nature. Three groups of aromatic amines have been recognized: monocyclic, polycyclic, and heterocyclic aromatic amines. Bacterial degradation of several monocyclic aromatic amines has been studied in a variety of bacteria, which utilizes monocyclic aromatic amines as their sole source of carbon and energy. Several degradation pathways have been proposed and the related enzymes and genes have also been characterized. Many reviews have been reviewed toxicity of monocyclic aromatic amines; however, there is lack of review on biodegradation of monocyclic aromatic amines. The aim of this review is to summarize bacterial degradation of monocyclic aromatic amines. This review will increase our current understanding of biochemical and molecular basis of bacterial degradation of monocyclic aromatic amines. PMID:26347719

  3. Analysis of heterocyclic aromatic amines.

    PubMed

    Murkovic, M

    2007-09-01

    Heterocyclic aromatic amines are formed in protein and amino acid-rich foods at temperatures above 150 degrees C. Of more than twenty heterocyclic aromatic amines identified ten have been shown to have carcinogenic potential. As nutritional hazards, their reliable determination in prepared food, their uptake and elimination in living organisms, including humans, and assessment of associated risks are important food-safety issues. The concentration in foods is normally in the low ng g(-1) range, which poses a challenge to the analytical chemist. Because of the complex nature of food matrixes, clean-up and enrichment of the extracts are also complex, usually involving both cation-exchange (propylsulfonic acid silica gel, PRS) and reversed-phase purification. The application of novel solid-phase extraction cartridges with a wettable apolar phase combined with cation-exchange characteristics simplified this process--both the polar and apolar heterocyclic aromatic amines were recovered in one fraction. Copper phthalocyanine trisulfonate bonded to cotton ("blue cotton") or rayon, and molecular imprinted polymers have also been successfully used for one-step sample clean-up. For analysis of the heterocyclic aromatic amines, liquid chromatography with base-deactivated reversed-phase columns has been used, and, recently, semi-micro and capillary columns have been introduced. The photometric, fluorimetric, or electrochemical detectors used previously have been replaced by mass spectrometers. Increased specificity and sub-ppb sensitivities have been achieved by the use of the selected-reaction-monitoring mode of detection of advanced MS instrumentation, for example the triple quadrupole and Q-TOF instrument combination. Gas chromatography, also with mass-selective detection, has been used for specific applications; the extra derivatization step needed for volatilization has been balanced by the higher chromatographic resolution. PMID:17546447

  4. Sodium Perborate Oxidation of an Aromatic Amine

    ERIC Educational Resources Information Center

    Juestis, Laurence

    1977-01-01

    Describes an experiment involving the oxidation of aromatic primary amines to the corresponding azo compound; suggests procedures for studying factors that influence the yield of such a reaction, including the choice of solvent and the oxidant-amine ratio. (MLH)

  5. Sediment-Associated Reactions of Aromatic Amines

    EPA Science Inventory

    Sorption of aromatic amines to sediments and soils can occur by both reversible physical processes and irreversible chemical processes. To elucidate the significance of these sorption pathways, the sorption kinetics of aniline and pyridine were studied in resaturated pond sedimen...

  6. SEDIMENT-ASSOCIATED REACTIONS OF AROMATIC AMINES. 2. QSAR DEVELOPMENT

    EPA Science Inventory

    The fate of aromatic amines in soils and sediments is dominated by irreversible binding through nucleophilic addition and oxidative radical coupling. Despite the common occurrence of the aromatic amine functional group in organic chemicals, the molecular properties useful for pr...

  7. SEDIMENT-ASSOCIATED REACTIONS OF AROMATIC AMINES: QSAR DEVELOPMENT

    EPA Science Inventory

    Despite the common occurrence of the aromatic amine functional group in environmental contaminants, few quantitative structure-activity relationships (QSARs) have been developed to predict sorption kinetics for aromatic amines in natural soils and sediments. Towards the goal of d...

  8. 40 CFR 721.750 - Aromatic amine compound.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aromatic amine compound. 721.750... Substances § 721.750 Aromatic amine compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic amine compound (PMN P-86-334) is subject to reporting...

  9. 40 CFR 721.750 - Aromatic amine compound.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aromatic amine compound. 721.750... Substances § 721.750 Aromatic amine compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic amine compound (PMN P-86-334) is subject to reporting...

  10. 40 CFR 721.750 - Aromatic amine compound.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aromatic amine compound. 721.750... Substances § 721.750 Aromatic amine compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic amine compound (PMN P-86-334) is subject to reporting...

  11. 40 CFR 721.750 - Aromatic amine compound.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic amine compound. 721.750... Substances § 721.750 Aromatic amine compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic amine compound (PMN P-86-334) is subject to reporting...

  12. 40 CFR 721.750 - Aromatic amine compound.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aromatic amine compound. 721.750... Substances § 721.750 Aromatic amine compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic amine compound (PMN P-86-334) is subject to reporting...

  13. DETERMINATION OF AROMATIC AMINES IN SOILS

    EPA Science Inventory

    A rapid liquid chromatographic(LC)method with ultraviolet(UV)or fluorescence detection was developed for parts-per-billion levels of aromatic amines in soils. 2,4-Diaminotoluene, pyridine,aniline,2-picoline,2-toluidine,5-nitro-2-toluidine,2-methyl-6-ethylaniline,4-aminobiphenyl,4...

  14. Complexes of onium salts with aromatic amines

    SciTech Connect

    Ivanov, G.E.; Pavlyuk, G.V.

    1987-11-10

    The following onium salts were used as acceptor components in these studies: acridinium perchlorate and iodide, thioxanthilium perchlorate, xanthilium perchlorate, and triphenylmethyl perchlorate. The following amines were examined as potential donor components: aniline, p-toluidine, diphenylamine, N-benzylaniline, N,N-dimethylaniline, N,N-dimethyl-p-toluidine, pyridine, ..gamma..-picoline, and 2-(p-dimethylaminostyryl)quinoline. The identification of complexes was carried out by measuring the changes in the electrical conductivity of solutions of onium salts and their mixtures with aromatic amines.

  15. Metabolism and Biomarkers of Heterocyclic Aromatic Amines in Molecular Epidemiology Studies: Lessons Learned from Aromatic Amines

    PubMed Central

    2011-01-01

    Aromatic amines and heterocyclic aromatic amines (HAAs) are structurally related classes of carcinogens that are formed during the combustion of tobacco or during the high-temperature cooking of meats. Both classes of procarcinogens undergo metabolic activation by N-hydroxylation of the exocyclic amine group, to produce a common proposed intermediate, the arylnitrenium ion, which is the critical metabolite implicated in toxicity and DNA damage. However, the biochemistry and chemical properties of these compounds are distinct and different biomarkers of aromatic amines and HAAs have been developed for human biomonitoring studies. Hemoglobin adducts have been extensively used as biomarkers to monitor occupational and environmental exposures to a number of aromatic amines; however, HAAs do not form hemoglobin adducts at appreciable levels and other biomarkers have been sought. A number of epidemiologic studies that have investigated dietary consumption of well-done meat in relation to various tumor sites reported a positive association between cancer risk and well-done meat consumption, although some studies have shown no associations between well-done meat and cancer risk. A major limiting factor in most epidemiological studies is the uncertainty in quantitative estimates of chronic exposure to HAAs and, thus, the association of HAAs formed in cooked meat and cancer risk has been difficult to establish. There is a critical need to establish long-term biomarkers of HAAs that can be implemented in molecular epidemioIogy studies. In this review article, we highlight and contrast the biochemistry of several prototypical carcinogenic aromatic amines and HAAs to which humans are chronically exposed. The biochemical properties and the impact of polymorphisms of the major xenobiotic-metabolizing enzymes on the biological effects of these chemicals are examined. Lastly, the analytical approaches that have been successfully employed to biomonitor aromatic amines and HAAs, and

  16. High-pressure liquid chromatography of aromatic amines

    NASA Technical Reports Server (NTRS)

    Young, P. R.

    1979-01-01

    Analysis made on commercially available liquid chromatograph demonstrates high-pressure liquid chromatographic conditions for separation of approximately 50 aromatic amines ranging from simple aniline derivatives to complex multiring di- and tri-amines.

  17. Basicity of aromatic amines from liquid chromatographic behavior

    NASA Technical Reports Server (NTRS)

    Young, P. R.; Mcnair, H. M.

    1975-01-01

    A liquid chromatographic investigation was conducted to determine whether the adsorption of weakly basic aromatic amines on slightly acidic silica gel adsorbents could be used to study their relative basicity. Under proper conditions, a linear correlation between pKb and log of capacity factor was observed. This finding may prove useful in helping to predict the relative basicity of closely related aromatic diamines, especially new amines being synthesized for polymer synthesis.

  18. Detection of azo dyes and aromatic amines in women undergarment.

    PubMed

    Nguyen, Thao; Saleh, Mahmoud A

    2016-07-28

    Women are exposed to several chemical additives including azo dyes that exist in textile materials, which are a potential health hazard for consumers. Our objective was to analyze suspected carcinogenic azo dyes and their degradation aromatic amines in women underwear panties using a fast and simple method for quantification. Here, we evaluated 120 different samples of women underwear for their potential release of aromatic amines to the skin. Seventy-four samples yielded low level mixtures of aromatic amines; however eighteen samples were found to produce greater than 200 mg/kg (ppm) of aromatic amines. Azo dyes in these 18 samples were extracted from the fabrics and analyzed by reverse phase thin layer chromatography in tandem with atmospheric pressure chemical ionization mass spectrometry. Eleven azo dyes were identified based on their mass spectral data and the chemical structure of the aromatic amine produced from these samples. We demonstrate that planar chromatography and mass spectrometry can be really helpful in confirming the identity of the azo dyes, offering highly relevant molecular information of the responsible compounds in the fabrics. With the growing concern about the consumer goods, analysis of aromatic amines in garments has become a highly important issue. PMID:27149414

  19. 40 CFR 721.10705 - Aromatic amine with cyclo amino carbonyls (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aromatic amine with cyclo amino... Specific Chemical Substances § 721.10705 Aromatic amine with cyclo amino carbonyls (generic). (a) Chemical... as aromatic amine with cyclo amino carbonyls (PMN P-12-572) is subject to reporting under...

  20. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    DOEpatents

    Smith, R.E.; Dolbeare, F.A.

    1980-10-21

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 4-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes. No Drawings

  1. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    DOEpatents

    Smith, Robert E. [557 Escondido Cir., Livermore, CA 94550; Dolbeare, Frank A. [5178 Diane La., Livermore, CA 94550

    1980-10-21

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 4-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes.

  2. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    DOEpatents

    Smith, Robert E.; Dolbeare, Frank A.

    1979-01-01

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 5-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes.

  3. AROMATIC AMINES IN AND NEAR THE BUFFALO RIVER

    EPA Science Inventory

    Three sediment samples taken from the Buffalo River and two soil samples taken near its bank have been analyzed for 2-propanol-extractable, basic organic compounds by using GC/MS. Eleven aromatic amines related to the commercial production of malachite green and crystal violet we...

  4. Amination of electrophilic aromatic compounds by vicarious nucleophilic substitution

    SciTech Connect

    Mitchell, A.R.; Pagoria, P.F.; Schmidt, R.D.

    2000-05-30

    The present invention relates to a process to aminate electrophilic aromatic compounds by vicarious nucleophilic substitution of hydrogen using quaternary hydrazinium salts. The use of trialkylhydrazinium halide, e.g., trimethylhydrazinium iodide, as well as hydroxylamine, alkoxylamines, and 4-amino-1,2,4-triazole to produce aminated aromatic structures, such as 1,3-diamino-2,4,6-trinitrobenzene (DATB), 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) and 3,5-diamino-2,4,6-trinitrotoluene (DATNT), is described. DATB and TATB are useful insensitive high explosives. TATB is also used for the preparation of benzenehexamine, a starting material for the synthesis of novel materials (optical imaging devices, liquid crystals, ferromagnetic compounds).

  5. Amination of electrophilic aromatic compounds by vicarious nucleophilic substitution

    DOEpatents

    Mitchell, Alexander R.; Pagoria, Philip F.; Schmidt, Robert D.

    2000-01-01

    The present invention relates to a process to aminate electrophilic aromatic compounds by vicarious nucleophilic substitution of hydrogen using quaternary hydrazinium salts. The use of trialkylhydrazinium halide, e.g., trimethylhydrazinium iodide, as well as hydroxylamine, alkoxylamines, and 4-amino-1,2,4-triazole to produce aminated aromatic structures, such as 1,3-diamino-2,4,6-trinitrobenzene (DATB), 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) and 3,5-diamino-2,4,6-trinitrotoluene (DATNT), is described. DATB and TATB are useful insensitive high explosives. TATB is also used for the preparation of benzenehexamine, a starting material for the synthesis of novel materials (optical imaging devices, liquid crystals, ferromagnetic compounds).

  6. Bacterial fermentation platform for producing artificial aromatic amines.

    PubMed

    Masuo, Shunsuke; Zhou, Shengmin; Kaneko, Tatsuo; Takaya, Naoki

    2016-01-01

    Aromatic amines containing an aminobenzene or an aniline moiety comprise versatile natural and artificial compounds including bioactive molecules and resources for advanced materials. However, a bio-production platform has not been implemented. Here we constructed a bacterial platform for para-substituted aminobenzene relatives of aromatic amines via enzymes in an alternate shikimate pathway predicted in a Pseudomonad bacterium. Optimization of the metabolic pathway in Escherichia coli cells converted biomass glucose to 4-aminophenylalanine with high efficiency (4.4 g L(-1) in fed-batch cultivation). We designed and produced artificial pathways that mimicked the fungal Ehrlich pathway in E. coli and converted 4-aminophenylalanine into 4-aminophenylethanol and 4-aminophenylacetate at 90% molar yields. Combining these conversion systems or fungal phenylalanine decarboxylases, the 4-aminophenylalanine-producing platform fermented glucose to 4-aminophenylethanol, 4-aminophenylacetate, and 4-phenylethylamine. This original bacterial platform for producing artificial aromatic amines highlights their potential as heteroatoms containing bio-based materials that can replace those derived from petroleum. PMID:27167511

  7. Bacterial fermentation platform for producing artificial aromatic amines

    PubMed Central

    Masuo, Shunsuke; Zhou, Shengmin; Kaneko, Tatsuo; Takaya, Naoki

    2016-01-01

    Aromatic amines containing an aminobenzene or an aniline moiety comprise versatile natural and artificial compounds including bioactive molecules and resources for advanced materials. However, a bio-production platform has not been implemented. Here we constructed a bacterial platform for para-substituted aminobenzene relatives of aromatic amines via enzymes in an alternate shikimate pathway predicted in a Pseudomonad bacterium. Optimization of the metabolic pathway in Escherichia coli cells converted biomass glucose to 4-aminophenylalanine with high efficiency (4.4 g L−1 in fed-batch cultivation). We designed and produced artificial pathways that mimicked the fungal Ehrlich pathway in E. coli and converted 4-aminophenylalanine into 4-aminophenylethanol and 4-aminophenylacetate at 90% molar yields. Combining these conversion systems or fungal phenylalanine decarboxylases, the 4-aminophenylalanine-producing platform fermented glucose to 4-aminophenylethanol, 4-aminophenylacetate, and 4-phenylethylamine. This original bacterial platform for producing artificial aromatic amines highlights their potential as heteroatoms containing bio-based materials that can replace those derived from petroleum. PMID:27167511

  8. Covalent Binding of Aromatic Amines to Natural Organic Matter: Study of Reaction Mechanisms and Development of Remediation Schemes

    EPA Science Inventory

    Aromatic amines comprise an important class of environmental contaminants. Concern over their environmental fate arises from the toxic effects that certain aromatic amines exhibit toward microbial populations and reports that they can be toxic or carcinogenic to animals. Aromatic...

  9. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  10. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  11. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  12. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  13. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  14. Molecular dosimetry of aromatic amines in human populations

    SciTech Connect

    Skipper, P.L.; Tannenbaum, S.R.

    1994-10-01

    Certain aromatic amines carcinogenic for the human urinary bladder, such as 4-aminobiphenyl, undergo hepatic metabolic activation to N-hydroxylamines, which are transported to the bladder. During the transport process, these reactive species come in contact with hemoglobin and react with this blood protein. The principal hemoglobin adduct formed is a cysteine sulfinamide, and quantitative methods have been developed for the analysis of sulfinamide adducts at the levels present in ordinary human blood specimens. N-acetylation is an alternative metabolic fate to N-hydroxylation. The amount of hemoglobin adduct is decreased to the extent that this pathway is increased relative to N-hydroxylation. Thus, the hemoglobin adduct is sensitive to dose, cytochrome P-450-mediated activation, and N-acetyltransferase-mediated detoxification. In addition, it has been shown that DNA adduct concentration of 4-aminobiphenyl present in human bladder epithelial cells is significantly associated with hemoglobin adduct levels. Thus, the hemoglobin adduct of 4-aminobiphenyl, and perhaps several other aromatic amines, is a good dosimeter for the target tissue dose of the ultimate carcinogenic metabolite of these amines. Several studies have been undertaken in which the hemoglobin adducts of aminobiphenyls in human blood specimens were determined quantitatively. Information concerning exposure status and acetylator phenotype of the same individuals was obtained simultaneously. The results of these studies indicate that the hemoglobin adduct of 4-aminobiphenyl is closely associated with three major risk factors for bladder cancer; cigarette smoking, type of tobacco smoked, and acetylator phenotype. They also support a major etiologic role for aromatic amines in much of human bladder cancer. 42 refs., 4 figs., 1 tab.

  15. A quantitative study of aromatic amine permeation through protective gloves using amine adsorptive pads.

    PubMed

    Vo, E; Berardinelli, S P; Hall, R C; El Ayouby, N

    2000-01-01

    A quantitative study of aromatic amine permeation through a glove material using Permea-Tec aromatic amine pads, used for the detection of chemical breakthrough of protective clothing, was performed for aniline following the microwave extraction process and gas chromatographic analysis. Aniline exhibited >99% adsorption on the pads at a spiking level of 1.94 mg (1.9 microL). Aniline showed recoveries from 65 to 89% (RSD < or =5.6%) over the range 1.1-1.9 microL (1.12-1.94 mg) of aniline applied to pads. The modified ASTM F739 and direct permeability testing procedures were used to determine breakthrough times for five protective glove materials using aniline as a challenge chemical. Breakthrough times for six protective gloves were determined, ranging from 182 sec to 82 min. The quantitative concentration of aniline on the pads following permeation through the gloves also was determined, ranging from 0.53 to 0.55 mg/cm2 (1.79-1.88 mg/pad). PMID:11192217

  16. Ligand-exchange chromatography of aromatic amines on resin-bound cobalt ion

    SciTech Connect

    Pehlivan, E.; Vural, U.S.; Ayar, A.; Yildiz, S.

    1996-06-01

    The use of cobalt metal for the selective separation of aromatic amines is completed with a chemically bonded diamine and glyoxime functional groups onto Lycopodium clavatum. Oximes and amines are excellent complexing agents for transition metal ions. Cobalt(II) metal ions can easily be immobilized on bis-diaminoethyl-glyoximated sporopollenin (bDAEG-sporopollenin). The ligand-exchange behavior of modified Lycopodium clavatum with respect to aromatic amines was investigated. This will permit the evaluation of bDAEG-sporopollenin ligand exchangers for their utilization as sorbents in the recovery, pollution control, and elimination of amines from wastewater.

  17. Prediction of aromatic amine carcinogenicity: QSAR base on calculated delocalizibility of hypothetical nitrenium ion intermediate

    SciTech Connect

    Purdy, R.

    1995-12-31

    Predictors for the reactivity of primary aromatic amines were hypothesized and tested on a small set of amines. It was found that the delocalizibility on the nitrogen of the previously hypothesized nitrenium ion intermediate was the only good predictor. The strength of this predictor was tested on a larger set of amines and a cut off value for discriminating between carcinogens and noncarcinogens was chosen. This QSAR supports the hypothesis that a nitrenium ion is an intermediate in the activation of primary aromatic amines to active carcinogens.

  18. [Urothelial carcinoma related to exposure to aromatic amines].

    PubMed

    Naito, S; Kumazawa, J

    1989-12-01

    Clinical and statistical observations were made on a group of 438 persons who had worked with aromatic amines (benzidine, 2-naphthylamine, 1-naphthylamine and dianisidine) with reference to their carcinogenic properties in the urinary tract. Urinary tract tumors developed in 68 (15.5%), with an average latent period of 22 years and 11 months. In these 68 cases, upper urinary tract tumors were found in 16 cases, 8 of which had bilateral lesions. The average age of onset was 48.1 ranging from 24 to 79. The incidence of tumors increased with the length of exposure to the amines. There was no finding that smoking habit increased the incidence of tumors in this group. Of the 49 new patients with bladder tumor, urine cytology was positive in 24 (49.0%) and suspicious of malignancy in 10 (20.4%), respectively. This indicated that it could be a useful screening test. Transurethral surgery was most frequently performed as an initial treatment. Recurrence occurred in 50 cases (73.5%), but 5-, 10- and 20-year-survival rates were 89.0 79.3 and 64.7%, respectively, showing a good prognosis. Malignant tumors in other organs developed in 18 (4.1%) of the 438 workers. The incidence of such malignant tumors was significantly higher in the workers who had been exposed to 2-naphthylamine than in others. Our data indicate that close observation is still necessary for early detection of patient with new or recurrent urothelial carcinoma in this group. PMID:2618901

  19. SEDIMENT-ASSOCIATED REACTIONS OF AROMATIC AMINES: 1. ELUCIDATION OF SORPTION MECHANISMS

    EPA Science Inventory

    Sorption of aromatic amines to sediments and soils can occur by both reversible physical processes and irreversible chemical processes. To elucidate the significance of these sorption pathways, the sorption kinetics of aniline and pyridine were studied in resaturated pond sedimen...

  20. Facile synthesis of unsymmetrical acridines and phenazines by a Rh(III)-catalyzed amination/cyclization/aromatization cascade.

    PubMed

    Lian, Yajing; Hummel, Joshua R; Bergman, Robert G; Ellman, Jonathan A

    2013-08-28

    We report formal [3 + 3] annulations of aromatic azides with aromatic imines and azobenzenes to give acridines and phenazines, respectively. These transformations proceed through a cascade process of Rh(III)-catalyzed amination followed by intramolecular electrophilic aromatic substitution and aromatization. Acridines can be directly prepared from aromatic aldehydes by in situ imine formation using catalytic benzylamine. PMID:23957711

  1. Facile Synthesis of Unsymmetrical Acridines and Phenazines by a Rhodium(III)-Catalyzed Amination, Cyclization and Aromatization Cascade

    PubMed Central

    Lian, Yajing; Hummel, Joshua R.; Bergman, Robert G.; Ellman, Jonathan A.

    2013-01-01

    New formal [3 + 3] annulations have been developed to obtain acridines and phenazines from aromatic azides and aromatic imines and azobenzenes, respectively. These transformations proceed through a cascade process of Rh(III)-catalyzed amination followed by intramolecular electrophilic aromatic substitution and aromatization. Acridines can be directly prepared from aromatic aldehydes by in situ imine formation using catalytic benzylamine. PMID:23957711

  2. Seasonal variations of atmospheric heterocyclic aromatic amines in Beijing, China

    NASA Astrophysics Data System (ADS)

    Dong, Xueling; Liu, Dameng; Gao, Shaopeng

    2013-02-01

    Heterocyclic aromatic amines (HAAs) belong to a group of substances associated with a high mutagenic and carcinogenic potential. This study reports that carcinogenic HAAs may be present in airborne particles. Airborne particles (PM10) were sampled from March 2005 to January 2006 at four urban sites in Beijing. Collected particulate matter was analyzed for six HAAs using high-performance liquid chromatography (HPLC) with fluorescence and UV detection. Clear seasonal variations of HAAs were observed with seasonal mass concentrations ranging from 0.66 ± 0.20 ng m- 3 (summer) to 19.76 ± 14.38 ng m- 3 (autumn). The carcinogenic amino-imidazo-azaarenes, including 2-Amino-3-methyl-3H-imidazo[4,5-f] quinoline (IQ), 2-Amino-3,4-dimethyl-3H-imidazo[4,5-f] quinoline (MeIQ), and 2-Amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP), were the major components with 75.2-87.0% of the total HAAs during the whole year except for summer. 3-Amino-1-methyl-5H-pyrido[3,4-b] indole (Trp-P-2), 2-Amino-9H-pyrido[2,3-b] indole (AαC), and 2-Amino-3-methyl-9H-pyrido[2,3-b] indole (MeAαC), with similar structures, were found to have similar seasonal patterns and strong correlations (r = 0.63-0.90) throughout the observation, which indicates that they most likely come from similar emission sources. Positive correlations between site-specific HAA concentrations and the relative humidity were observed. Of the different sites studied, the total HAA concentrations were most abundant at commercial sites and the smallest at residential sites. The combustion aerosols emitted from cooking, coal, and petroleum may be the sources of these carcinogens in the atmosphere, and cooking emissions may probably play an important role in Beijing's HAAs pollution.

  3. Analysis of cooked foods for new heterocyclic aromatic amines

    SciTech Connect

    Knize, M.G.; Felton, J.S.

    1997-12-31

    Heterocyclic aromatic amines (HAA), which are formed in meats during cooking, are a potential dietary health hazard as they are potent mutagens in bacterial test systems and carcinogens in laboratory animals. Several novel HAA have been (partially) characterized in cooked foods: dimethylimidazopyridine (DMIP), a trimethylimidazopyridine (TMIP), and dimethylimidazofuropyridine (IFP). A solid-phase-extraction method for the analysis of these compounds was developed. Samples were homogenized in 0.1 M HCl:CH3OH (7:3), centrifuged and the supernatant applied to a C18 cartridge coupled to an SCX cartridge. The C18 cartridge trapped contaminants while allowing the HAA to pass to the SCX cartridge where they were retained. The C18 cartridge was discarded, while the SCX cartridge was washed sequentially with 0.1 M HCl, CH3OH, water, and 1 M CH3COONH4. HAA were eluted with CH3OH:NH4OH (9:1), dried under nitrogen, redissolved in CH2Cl2:CH3OH (19:1), and applied to a PRS cartridge. The PRS cartridge was washed with 0.1 M HCl, 0.1 M HCl:CH3OH (3:2), and water before elution with CH3OH:NH4OH (9:1). The purified extract was analyzed by reversed phase HPLC with UV and fluorescence detection. The presence of DMIP, 1,5,6-TMIP, and IFP was detected in grilled and pan-fried ground beef. Recoveries of the new HAA for this extraction procedure will be presented.

  4. An Acetyltransferase Conferring Tolerance to Toxic Aromatic Amine Chemicals

    PubMed Central

    Martins, Marta; Rodrigues-Lima, Fernando; Dairou, Julien; Lamouri, Aazdine; Malagnac, Fabienne; Silar, Philippe; Dupret, Jean-Marie

    2009-01-01

    Aromatic amines (AA) are a major class of environmental pollutants that have been shown to have genotoxic and cytotoxic potentials toward most living organisms. Fungi are able to tolerate a diverse range of chemical compounds including certain AA and have long been used as models to understand general biological processes. Deciphering the mechanisms underlying this tolerance may improve our understanding of the adaptation of organisms to stressful environments and pave the way for novel pharmaceutical and/or biotechnological applications. We have identified and characterized two arylamine N-acetyltransferase (NAT) enzymes (PaNAT1 and PaNAT2) from the model fungus Podospora anserina that acetylate a wide range of AA. Targeted gene disruption experiments revealed that PaNAT2 was required for the growth and survival of the fungus in the presence of toxic AA. Functional studies using the knock-out strains and chemically acetylated AA indicated that tolerance of P. anserina to toxic AA was due to the N-acetylation of these chemicals by PaNAT2. Moreover, we provide proof-of-concept remediation experiments where P. anserina, through its PaNAT2 enzyme, is able to detoxify the highly toxic pesticide residue 3,4-dichloroaniline in experimentally contaminated soil samples. Overall, our data show that a single xenobiotic-metabolizing enzyme can mediate tolerance to a major class of pollutants in a eukaryotic species. These findings expand the understanding of the role of xenobiotic-metabolizing enzyme and in particular of NATs in the adaptation of organisms to their chemical environment and provide a basis for new systems for the bioremediation of contaminated soils. PMID:19416981

  5. Metal-Free Reduction of Aromatic Nitro Compounds to Aromatic Amines with B2pin2 in Isopropanol.

    PubMed

    Lu, Hongtao; Geng, Zhiyue; Li, Jingya; Zou, Dapeng; Wu, Yusheng; Wu, Yangjie

    2016-06-01

    A metal-free reduction of aromatic nitro compounds to the corresponding amines has been achieved by a combination of B2pin2 and KOtBu in isopropanol. A series of nitro compounds containing various reducible functional groups were chemoselectively reduced in good to excellent yields. PMID:27214590

  6. Structure-Activity Relationships for Rates of Aromatic Amine Oxidation by Manganese Dioxide.

    PubMed

    Salter-Blanc, Alexandra J; Bylaska, Eric J; Lyon, Molly A; Ness, Stuart C; Tratnyek, Paul G

    2016-05-17

    New energetic compounds are designed to minimize their potential environmental impacts, which includes their transformation and the fate and effects of their transformation products. The nitro groups of energetic compounds are readily reduced to amines, and the resulting aromatic amines are subject to oxidation and coupling reactions. Manganese dioxide (MnO2) is a common environmental oxidant and model system for kinetic studies of aromatic amine oxidation. In this study, a training set of new and previously reported kinetic data for the oxidation of model and energetic-derived aromatic amines was assembled and subjected to correlation analysis against descriptor variables that ranged from general purpose [Hammett σ constants (σ(-)), pKas of the amines, and energies of the highest occupied molecular orbital (EHOMO)] to specific for the likely rate-limiting step [one-electron oxidation potentials (Eox)]. The selection of calculated descriptors (pKa, EHOMO, and Eox) was based on validation with experimental data. All of the correlations gave satisfactory quantitative structure-activity relationships (QSARs), but they improved with the specificity of the descriptor. The scope of correlation analysis was extended beyond MnO2 to include literature data on aromatic amine oxidation by other environmentally relevant oxidants (ozone, chlorine dioxide, and phosphate and carbonate radicals) by correlating relative rate constants (normalized to 4-chloroaniline) to EHOMO (calculated with a modest level of theory). PMID:27074054

  7. CHEMICAL INDUCTION OF TUMORS IN OYSTERS BY A MIXTURE OF AROMATIC AND CHLORINATED HYDROCARBONS, AMINES, AND METALS

    EPA Science Inventory

    Tumors were induced in eastern oysters (Crassotrea virginica) by a mixture f aromatic hydrocarbons, an aromatic amine, polychlori-nated biphenyls, chlorinated hydrocarbons, a nitrosoamine and heavy metals. idney and nteric tumors developed in oysters following exposure to a mixtu...

  8. Monomers for thermosetting and toughening epoxy resins. [glycidyl amine derivatives, propargyl-containing amines, and mutagenic testing of aromatic diamines

    NASA Technical Reports Server (NTRS)

    Pratt, J. R.

    1981-01-01

    Eight glycidyl amines were prepared by alkylating the parent amine with epichlorohydrin to form chlorohydrin, followed by cyclization with aqueous NaOH. Three of these compounds contained propargyl groups with postcuring studies. A procedure for quantitatively estimating the epoxy content of these glycidyl amines was employed for purity determination. Two diamond carbonates and several model propargly compounds were prepared. The synthesis of three new diamines, two which contain propargyloxy groups, and another with a sec-butyl group is in progress. These materials are at the dinitro stage ready for the final hydrogenation step. Four aromatic diamines were synthesized for mutagenic testing purposes. One of these compounds rapidly decomposes on exposure to air.

  9. Bioactivation of Heterocyclic Aromatic Amines by UDP Glucuronosyltransferases.

    PubMed

    Cai, Tingting; Yao, Lihua; Turesky, Robert J

    2016-05-16

    2-Amino-9H-pyrido[2,3-b]indole (AαC) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) are carcinogenic heterocyclic aromatic amines (HAA) that arise during the burning of tobacco and cooking of meats. UDP-glucuronosyltransferases (UGT) detoxicate many procarcinogens and their metabolites. The genotoxic N-hydroxylated metabolite of AαC, 2-hydroxyamino-9H-pyrido[2,3-b]indole (HONH-AαC), undergoes glucuronidation to form the isomeric glucuronide (Gluc) conjugates N(2)-(β-d-glucosidurony1)-2-hydroxyamino-9H-pyrido[2,3-b]indole (AαC-HON(2)-Gluc) and O-(β-d-glucosidurony1)-2-hydroxyamino-9H-pyrido[2,3-b]indole (AαC-HN(2)-O-Gluc). AαC-HON(2)-Gluc is a stable metabolite but AαC-HN(2)-O-Gluc is a biologically reactive intermediate, which covalently adducts to DNA at levels that are 20-fold higher than HONH-AαC. We measured the rates of formation of AαC-HON(2)-Gluc and AαC-HN(2)-O-Gluc in human organs: highest activity occurred with liver and kidney microsomes, and lesser activity was found with colon and rectum microsomes. AαC-HN(2)-O-Gluc formation was largely diminished in liver and kidney microsomes, by niflumic acid, a selective inhibitor UGT1A9. In contrast, AαC-HON(2)-Gluc formation was less affected and other UGT contribute to N(2)-glucuronidation of HONH-AαC. UGT were reported to catalyze the formation of isomeric Gluc conjugates at the N(2) and N3 atoms of 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (HONH-PhIP), the genotoxic metabolite of PhIP. However, we found that the N3-Gluc of HONH-PhIP also covalently bound to DNA at higher levels than HONH-PhIP. The product ion spectra of this Gluc conjugate acquired by ion trap mass spectrometry revealed that the Gluc moiety was linked to the oxygen atom of HONH-PhIP and not the N3 imidazole atom of the oxime tautomer of HONH-PhIP as was originally proposed. UGT1A9, an abundant UGT isoform expressed in human liver and kidney, preferentially forms the O-linked Gluc conjugates of HONH

  10. Spectrofluorimetric evaluation of total aliphatic and aromatic amines in well waters and wastewaters

    SciTech Connect

    Djozan, D.; Faraj-Zadeh, M.A.

    1998-09-01

    Aliphatic and aromatic amines are important metabolic intermediates in decomposition processes and are distributed in wastewaters. Monitoring of these compounds in the water samples can indicate whether the environmental waters are contaminated with wastewaters. A simple and rapid spectrofluorimetric method is described for the determination of aliphatic and aromatic amines on the basis of ammonia and aniline, respectively. Aromatic amines in samples were reacted at pH 5.5 with fluram immobilized on an Octadecylsilane Solid Phase Extraction (ODS-SPE) cartridge. The produced pyrrolinones were adsorbed on SPE and separated from the aliphatic amines. Analysis of these compounds was carried out by elution of SPE with 1 ml Tetrahydrofuran (THF) and determination of fluorescence intensity at excitation wavelength 400 nm and emission wavelength 475 nm. Aliphatic amines after passing from SPE were collected and reacted with fluram at pH 9.2, and extracted into dichloromethane at pH 3 and quantitated fluorimetrically. Linear dynamic ranges and detection limits (LOD) were 1-20, 0.43 mg l{sup {minus}1} and 1-200, 0.39 {micro}g l{sup {minus}1} for ammonia and aniline, respectively. The proposed method was successfully applied for the evaluation of these compounds in local well waters and municipality wastewaters.

  11. INFLUENCE OF LIGNIN ON THE ADSORPTION OF HETERO-CYCLIC AROMATIC AMINES BY INSOLUBLE FIBER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The prevention of colon cancer by dietary fiber is widely discussed. One possible mechanism is by adsorbing carcinogens and transporting them out of the body. It was shown that several model dietary fibers are able to adsorb heterocyclic aromatic amines (HAAs), a group of carcinogens mostly found in...

  12. Ruthenium/Imidazolylphosphine catalysis: hydrogenation of aliphatic and aromatic nitriles to form amines.

    PubMed

    Werkmeister, Svenja; Junge, Kathrin; Wendt, Bianca; Spannenberg, Anke; Jiao, Haijun; Bornschein, Christoph; Beller, Matthias

    2014-04-01

    A convenient and efficient catalyst system for the hydrogenation of aliphatic nitriles towards the corresponding primary amines in high to excellent yields is presented. In addition, aromatic nitriles are reduced smoothly, too. The use of low catalyst loadings and molecular hydrogen make this protocol an attractive methodology. PMID:24615766

  13. Structural analysis of aliphatic versus aromatic substrate specificity in a copper amine oxidase from Hansenula polymorpha.

    PubMed

    Klema, Valerie J; Solheid, Corinne J; Klinman, Judith P; Wilmot, Carrie M

    2013-04-01

    Copper amine oxidases (CAOs) are responsible for the oxidative deamination of primary amines to their corresponding aldehydes. The CAO catalytic mechanism can be divided into two half-reactions: a reductive half-reaction in which a primary amine substrate is oxidized to its corresponding aldehyde with the concomitant reduction of the organic cofactor 2,4,5-trihydroxyphenylalanine quinone (TPQ) and an oxidative half-reaction in which reduced TPQ is reoxidized with the reduction of molecular oxygen to hydrogen peroxide. The reductive half-reaction proceeds via Schiff base chemistry, in which the primary amine substrate first attacks the C5 carbonyl of TPQ, forming a series of covalent Schiff base intermediates. The X-ray crystal structures of copper amine oxidase-1 from the yeast Hansenula polymorpha (HPAO-1) in complex with ethylamine and benzylamine have been determined to resolutions of 2.18 and 2.25 Å, respectively. These structures reveal the two amine substrates bound at the back of the active site coincident with TPQ in its two-electron-reduced aminoquinol form. Rearrangements of particular amino acid side chains within the substrate channel and specific protein-substrate interactions provide insight into the substrate specificity of HPAO-1. These changes begin to account for this CAO's kinetic preference for small, aliphatic amines over the aromatic amines or whole peptides preferred by some of its homologues. PMID:23452079

  14. Removal of trace levels of aromatic amines from aqueous solution by foam flotation

    SciTech Connect

    Nyssen, G.A.; White, J.S. ); Bibring, P.; Wilson, D.J. )

    1990-04-01

    Aromatic amines, including 4-(t-butyl)pyridine, 4-(n-butyl)-aniline, benzylamine, 4-aminobiphenyl, 1- and 2-aminonaphthalene, and 2,6-xylidine were effectively removed from water by foam flotation with the anionic surfactant sodium dodecylsulfate (SDS). With initial amine concentrations of 10 mg/L or less, residual amine concentrations of less than 0.1 mg/L were generally obtained after 10-30 min of flotation. The SDS concentration and flotation time are directly related to the amount of amine removed. Amine removal is most efficient at pH values low enough so that the amine is protonated (usually about 3), and at low ionic strength. Alcohols up to 10% by volume do not appreciably affect amine removal. The mechanism of removal is dominated by ion-ion attraction between the surfactant and the protonated amine; there is also apparently some contribution from ion-dipole attraction. Benzidine is not removed effectively; evidently it is insufficiently hydrophobic.

  15. N-acetylation of three aromatic amine hair dye precursor molecules eliminates their genotoxic potential.

    PubMed

    Zeller, Andreas; Pfuhler, Stefan

    2014-01-01

    N-acetylation has been described as a detoxification reaction for aromatic amines; however, there is only limited data available showing that this metabolic conversion step changes their genotoxicity potential. To extend this database, three aromatic amines, all widely used as precursors in oxidative hair dye formulations, were chosen for this study: p-phenylenediamine (PPD), 2,5-diaminotoluene (DAT) and 4-amino-2-hydroxytoluene (AHT). Aiming at a deeper mechanistic understanding of the interplay between activation and detoxification for this chemical class, we compared the genotoxicity profiles of the parent compounds with those of their N-acetylated metabolites. While PPD, DAT and AHT all show genotoxic potential in vitro, their N-acetylated metabolites completely lack genotoxic potential as shown in the Salmonella typhimurium reversion assay, micronucleus test with cultured human lymphocytes (AHT), chromosome aberration assay with V79 cells (DAT) and Comet assay performed with V79 cells. For the bifunctional aromatic amines studied (PPD and DAT), monoacetylation was sufficient to completely abolish their genotoxic potential. Detoxification through N-acetylation was further confirmed by comparing PPD, DAT and AHT in the Comet assay using standard V79 cells (N-acetyltransferase (NAT) deficient) and two NAT-proficient cell lines,V79NAT1*4 and HaCaT (human keratinocytes). Here we observed a clear shift of dose-response curves towards decreased genotoxicity of the parent aromatic amines in the NAT-proficient cells. These findings suggest that genotoxic effects will only be found at concentrations where the N-acetylation (detoxifying) capacity of the cells is overwhelmed, indicating that a 'first-pass' effect in skin could be taken into account for risk assessment of these topically applied aromatic amines. The findings also indicate that the use of liver S-9 preparations, which generally underestimate Phase II reactions, contributes to the generation of irrelevant

  16. Aromatic Esters of Bicyclic Amines as Antimicrobials against Streptococcus pneumoniae.

    PubMed

    de Gracia Retamosa, María; Díez-Martínez, Roberto; Maestro, Beatriz; García-Fernández, Esther; de Waal, Bas; Meijer, E W; García, Pedro; Sanz, Jesús M

    2015-11-01

    A double approach was followed in the search of novel inhibitors of the surface choline-binding proteins (CBPs) of Streptococcus pneumoniae (pneumococcus) with antimicrobial properties. First, a library of 49 rationally-designed esters of alkyl amines was screened for their specific binding to CBPs. The best binders, being esters of bicyclic amines (EBAs), were then tested for their in vitro effect on pneumococcal growth and morphology. Second, the efficiency of EBA-induced CBP inhibition was enhanced about 45,000-fold by multivalency effects upon synthesizing a poly(propylene imine) dendrimer containing eight copies of an atropine derivative. Both approaches led to compounds that arrest bacterial growth, dramatically decrease cell viability, and exhibit a protection effect in animal disease models, demonstrating that the pneumococcal CBPs are adequate targets for the discovery of novel antimicrobials that overcome the currently increasing antimicrobial resistance issues. PMID:26377931

  17. Genotoxic potency in Drosophila melanogaster of selected aromatic amines and polycyclic aromatic hydrocarbons as assayed in the DNA repair test.

    PubMed

    Fujikawa, K; Fort, F L; Samejima, K; Sakamoto, Y

    1993-12-01

    Drosophila melanogaster stock consisting of meiotic recombination deficient (Rec-) double mutant mei-9a mei-41D5 males and Rec+ females was exposed at the larval stage to an aromatic amine or a polycyclic aromatic hydrocarbon. After emergence as adult flies, the males and the females were scored separately. When the treatment caused a dose-dependent reduction in the male to female ratio from the control level; the experiment was repeated with a larval stock consisting of Rec+ males and Rec+ females under comparable conditions. A preferential killing effect upon Rec- larvae was taken as evidence of DNA damaging effect of the test compound. Among 16 compounds tested, 1-AP, B(a)P, 2-AF, DAF, 4-AAF, 2-AAF, 1-AA, 2-AA, DMA, B(a)A and DMBA were registered as positive; Py and 3-MC were weakly positive; and B(e)P, Fluo and Ant were negative. The selective killing effects of the compounds in each of the pyrene, fluorene and anthracene series varied drastically as a function of structure in a way similar to that reported for the genotoxicity in Drosophila and the carcinogenicity in rodents. The Drosophila DNA repair assay will serve as a simple adjunct to the already available means for studying the genotoxic potency of aromatic amines and polycyclic aromatic hydrocarbons. PMID:7694108

  18. Food heating and the formation of heterocyclic aromatic amine mutagens/carcinogens

    SciTech Connect

    Knize, M.G.; Salmon, C.P.; Felton, J.S.

    1997-12-31

    Several heterocyclic amines that are mutagenic and carcinogenic have been found as cooking products of muscle meats and some grain-based foods. Amounts in meats range from undetectable levels (less than 0.5 ppb) after boiling, microwave-cooking, and baking, to tens to hundreds of ppb for frying/grilling at high temperatures. A mutagenic response, believed to be caused by aromatic amines, was shown with some toasted foods, but the identity of the mutagenic chemicals are different from those found in meats. The airborne products from cooking also contain many of the same heterocyclic amines. Commercial cooking generally forms less of the heterocyclic amines than home cooking due to industry cooking practices.

  19. Degradation of aromatic amines in textile-dyeing sludge by combining the ultrasound technique with potassium permanganate treatment.

    PubMed

    Liang, Jieying; Ning, Xun-An; An, Taicheng; Sun, Jian; Zhang, Yaping; Wang, Yujie

    2016-08-15

    This paper reports, for the first time, a combined technique of ultrasound (US) with KMnO4 degradation of aromatic amines in a textile-dyeing sludge. The reaction mechanisms and the degradation kinetics of aromatic amines at various operating parameters (KMnO4 dosage, US power density and pH) were systematically examined by the combined system of US-KMnO4. The results indicated that there was a synergistic effect between US and KMnO4, as US greatly enhanced KMnO4 in the degradation of aromatic amines and exhibited apparent sludge disintegration and separated pollutants from the sludge. In addition to accelerating the Mn(VII) reaction with pollutants in the filtrate, US also caused Mn(VII) to enter the porous sludge and sufficiently facilitated the reaction of the strongly absorbed aromatic amines. The combined treatment of US-KMnO4 was effective in the degradation of aromatic amines in textile-dyeing sludge. On average, 58.7% of monocyclic anilines, 88.3% of other forms of aromatic amines, and 24.0% of TOC were removed under the optimal operating conditions of a KMnO4 dosage of 12mM, an US power density of 1.80W/cm(3) and pH 5. The present study proposed US-KMnO4 treatment as a practical method for the disposal of aromatic amines in textile-dyeing sludge. PMID:27107230

  20. Selective determination of phenols and aromatic amines based on horseradish peroxidase-nanoporous gold co-catalytic strategy.

    PubMed

    Wu, Chao; Liu, Zhuang; Sun, Huihui; Wang, Xia; Xu, Ping

    2016-05-15

    Aromatic compounds, such as phenols and aromatic amines, are environmental contaminants suspected of posing human health risks. For phenols and aromatic amines reliable detection, promoting selectivity and sensitivity for phenols and aromatic amines is crucial in biosensor design. Here, a biosensor combined the advantages of both enzymatic and nonenzymatic electrochemical sensors is constructed. Nanoporous gold (NPG) is selected as an enzyme carrier for horseradish peroxidase (HRP) biosensor fabrication due to its three-dimension structure with unique properties. It is firstly discovered that NPG can achieve selective oxidation for phenols and aromatic amines. Thus, the electrochemical reaction on the resulting HRP/NPG/GCE bioelectrode is attributed to the co-catalysis of HRP and NPG. For the detection of catechol (Cat), 4-aminophenol (p-AP), o-phenylenediamine (o-PD), and p-phenylenediamine (p-PD), linear responses are observed in large concentration ranges with high sensitivities and low detection limits. Further, the HRP/NPG/GCE bioelectrode presents strong reproducibility, specificity, selectivity and anti-interference capability in detecting the mixture of phenols and aromatic amines along with a long shelf-life, and the real sea water sample analysis was achieved. These unique properties make the HRP/NPG/GCE bioelectrode an excellent choice for phenols and aromatic amines reliable detection. PMID:26780372

  1. Hydrogen-deuterium exchange of aromatic amines and amides using deuterated trifluoroacetic acid

    PubMed Central

    Giles, Richard; Lee, Amy; Jung, Erica; Kang, Aaron; Jung, Kyung Woon

    2014-01-01

    The H-D exchange of aromatic amines and amides, including pharmaceutically relevant compounds such as acetaminophen and diclofenac, was investigated using CF3COOD as both the sole reaction solvent and source of deuterium label. The described method is amenable to efficient deuterium incorporation for a wide variety of substrates possessing both electron-donating and electron-withdrawing substituents. Best results were seen with less basic anilines and highly activated acetanilides, reflecting the likelihood of different mechanistic pathways. PMID:25641994

  2. Catalytic oxidation of 2-aminophenols and ortho hydroxylation of aromatic amines by tyrosinase.

    PubMed

    Toussaint, O; Lerch, K

    1987-12-29

    The usual substrates of tyrosinase, a copper-containing monooxygenase (EC 1.14.18.1), are monophenols and o-diphenols which are both converted to o-quinones. In this paper, we studied the reaction of this enzyme with two new classes of substrates: aromatic amines and o-aminophenols, structural analogues of monophenols and o-diphenols, respectively. They undergo the same catalytic reactions (ortho hydroxylation and oxidation), as documented by product analysis and kinetic studies. In the presence of tyrosinase, arylamines and o-aminophenols are converted to o-quinone imines, which are isolated as quinone anils or phenoxazones. As an example, in the presence of tyrosinase, 2-amino-3-hydroxybenzoic acid (an o-aminophenol) is converted to cinnabarinic acid, a well-known phenoxazone, while p-aminotoluene (an aromatic amine) gives rise to the formation of 5-amino-2-methyl-1,4-benzoquinone 1-(4-methylanil). Kinetic studies using an oxygen electrode show that arylamines and the corresponding monophenols exhibit similar Michaelis constants (Km = 0.11-0.49 mM). In contrast, the reaction rates observed for aromatic amines are relatively slow (Kcat = 1-3 min-1) as compared to monophenols (1320-6960 min-1). The enzymatic conversion of arylamines by tyrosinase is different from the typical ones: N-oxidation and ring hydroxylation without further oxidation. This difference originates from the regiospecific hydroxylation (ortho position) and subsequent oxidation of the intermediate o-aminophenol to the corresponding o-quinone imine. Finally, the well-known monooxygenase activity of tyrosinase was also confirmed for the aromatic amine p-aminotoluene, with 18O2.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2964867

  3. Catalytic oxidation of 2-aminophenols and ortho hydroxylation of aromatic amines by tyrosinase

    SciTech Connect

    Toussaint, O.; Lerch, K.

    1987-12-29

    The usual substrates of tyrosinase, a copper-containing monooxygenase (EC 1.14.18.1), are monophenols and o-diphenols which are both converted to o-quinones. In this paper, the authors studied the reaction of this enzyme with two new classes of substrates: aromatic amines and o-aminophenols, structural analogues of monophenols and o-diphenols, respectively. They undergo the same catalytic reactions (ortho hydroxylation and oxidation), as documented by product analysis and kinetic studies. In the presence of tyrosinase, arylamines and o-aminophenols are converted to o-quinone imines, which are isolated as quinone anils or phenoxazones. As an example, in the presence of tyrosinase, 2-amino-3-hydroxybenzoic acid (an o-aminophenol) is converted to cinnabarinic acid, a well-known phenoxazone, while p-aminotoluene (an aromatic amine) gives rise to the formation of 5-amino-2-methyl-1,4-benzoquinone 1-(4-methylanil). Kinetic studies using an oxygen electrode show that arylamines and the corresponding monophenols exhibit similar Michaelis constants. In contrast, the reaction rates observed for aromatic amines are relatively slow as compared to monophenols. The enzymatic conversion of arylamines by tryosinase is different from the typical ones: N-oxidation and ring hydroxylation without further oxidation. This difference originates from the regiospecific hydroxylation (ortho position) and subsequent oxidation of the intermediate o-aminophenol to the corresponding o-quinone imine. Finally, the well-know monooxygenase activity of tyrosinase was also confirmed for the aromatic amine p-aminotoluene, with /sup 18/O/sub 2/.

  4. Removal of chlorine gas by an amine functionalized metal-organic framework via electrophilic aromatic substitution.

    PubMed

    DeCoste, Jared B; Browe, Matthew A; Wagner, George W; Rossin, Joseph A; Peterson, Gregory W

    2015-08-11

    Here we report the removal of chlorine gas from air via a reaction with an amine functionalized metal-organic framework (MOF). It is found that UiO-66-NH2 has the ability to remove 1.24 g of Cl2 per g of MOF via an electrophilic aromatic substitution reaction producing HCl, which is subsequently neutralized by the MOF. PMID:26146024

  5. Polymorphisms for aromatic amine metabolism in humans: relevance for human carcinogenesis.

    PubMed Central

    Kadlubar, F F; Butler, M A; Kaderlik, K R; Chou, H C; Lang, N P

    1992-01-01

    The metabolic pathways associated with carcinogenic aromatic amines in humans provide an excellent example of polymorphisms that appear to be relevant to human carcinogenesis. In this regard, the N-acetylation of arylamines and the O-acetylation of their N-hydroxy metabolites are catalyzed preferentially by a genetically polymorphic acetyltransferase, high activity of which has been correlated with decreased risk for urinary bladder cancer and increased susceptibility to colorectal cancer. Cytochrome P450IA2, the principal liver enzyme involved in aromatic amine N-oxidation, exhibits a wide interindividual variation that appears trimodal in several populations and is clearly inducible by cigarette smoking and probably other host factors as well. UDP-Glucuronosyltransferases, which catalyze the N-glucuronidation of N-hydroxyarylamines and are likely to be responsible for their transport to the colon, show widely varied but unimodal distributions in humans. In contrast, human liver sulfotransferase activity for N-hydroxyarylamines, which would be expected to decrease their transport through the circulation, is catalyzed by a polymorphic enzyme(s) that is expressed at higher levels in blacks, as compared to whites, and could contribute to their relatively lower incidence of urinary bladder cancer. Peroxidative activation of aromatic amines can also occur, especially from prostaglandin H synthase in the urinary bladder and myeloperoxidase in the lungs of cigarette smokers, and both show considerable individual variability, apparently due to the extent of tissue inflammation.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1486865

  6. Mutagenicity and aromatic amine content of fumes from heated cooking oils produced in Taiwan.

    PubMed

    Chiang, T A; Pei-Fen, W; Ying, L S; Wang, L F; Ko, Y C

    1999-01-01

    According to toxicological studies, there are several unidentified mutagens derived from cooking oil fumes appearing in kitchens of Chinese homes where women daily prepare food. Data are limited to an analysis of aromatic amines from cooking oil fumes, which are known to be carcinogenic for bladder cancer. Fume samples from three different commercial cooking oils frequently used in Taiwan were collected and analysed for mutagenicity in the Salmonella/microsome assay. Aromatic amines were extracted from the samples and identified by HPLC and confirmed by gas chromatography/mass spectrometry (GC/MS). Extracts from three cooking oil fumes were found to be mutagenic in the presence of S-9 mix. All samples contained 2-naphthylamine (2-NA) and 4-aminobiphenyl (4-ABP). Concentrations of 2-NA and 4-ABP were 31.5 and 35.7 microg/m3 in fumes from sunflower oil, 31.9 and 26.4 mg/m3 in vegetable oil, and 48.3 and 23.3 microg/m3 in refined-lard oil, respectively. Mutagenicities of the three cooking oil condensates were significantly reduced (P<0.05) by adding the antioxidant catechin (CAT) into the oils before heating. Significant difference existed between the amounts of aromatic amines with and without adding CAT (P<0.05). These results indicate that exposure to cooking oil fumes in Taiwan might be an important but controllable risk factor in the aetiology of bladder cancer. PMID:10227736

  7. A review of the selective catalytic reduction of aromatic nitro compounds into aromatic amines, isocyanates, carbamates, and ureas using CO

    SciTech Connect

    Tafesh, A.M.; Weiguny, J.

    1996-09-01

    Although the use of CO as a reductant had been in the past confined to few reactions, its use in organic synthesis, especially in the reductive carbonylation of nitro aromatics and the oxidative carbonylation of aromatic amines, has increased dramatically. Since the discovery of CO-induced reduction of nitro groups, there has been a wide spread increase of interest in the application and mechanistic understanding of this reaction. In a major review published in 1988 it was noted, that in practice no studies of the mechanism of N-carbonylation of aromatic nitro compounds with alcohols leading to carbamates have been carried out. This review clearly shows a major change since that publication. Indeed, metal-catalyzed reductive carbonylation of nitro aromatics using CO as reducing agent has been in the past 10 years the subject of intense investigation both in academia and in the chemical industry. Several articles and reviews have covered the subject up to the late 1980s. The authors will concentrate on more recent literature, but sometimes older data will be used to establish an understanding of these reactions. 127 refs.

  8. Anomalous length dependence of conductance of aromatic nanoribbons with amine anchoring groups

    NASA Astrophysics Data System (ADS)

    Bilić, Ante; Sanvito, Stefano

    2012-09-01

    Two sets of aromatic nanoribbons, based around a common hexagonal scaffolding, with single and dual terminal amine groups have been considered as potential molecular wires in a junction formed by gold leads. Charge transport through the two-terminal device has been modeled using density functional theory (with and without self-interaction correction) and the nonequilibrium Green's function method. The effects of wire length, multiple terminal contacts, and pathways across the junction have been investigated. For nanoribbons with the oligopyrene motif and conventional single amine terminal groups, an increase in the wire length causes an exponential drop in the conductance. In contrast, for the nanoribbons with the oligoperylene motif and dual amine anchoring groups the predicted conductance rises with the wire length over the whole range of investigated lengths. Only when the effects of self-interaction correction are taken into account, the conductance of the oligoperylene ribbons exhibits saturation for longer members of the series. The oligoperylene nanoribbons, with dual amine groups at both terminals, show the potential to fully harness the highly conjugated system of π molecular orbitals across the junction.

  9. Presence of heterocyclic aromatic amines (HAS) in smoked "Provola" cheese from Calabria (Italy).

    PubMed

    Naccari, C; Galceran, M T; Moyano, E; Cristani, M; Siracusa, L; Trombetta, D

    2009-02-01

    This study evaluated the residual levels of heterocyclic aromatic amines (HAs) in "Provola" cheese samples from Calabria, smoked using natural methods and using commercial buffered smoke. A comparative study of HAs concentrations was carried out on different portions of these samples: the rind, exterior part, core and on slice. Quantitative determination of HAs was carried out by HPLC using a fluorescence detector and analysis in HPLC-MS was conduced to confirm the presence of these amines. Residual levels of HAs were found in all naturally smoked "Provola" cheese samples. The results obtained showed that the smoking process performed using traditional methods contributes to HAs contamination while the use of commercial buffered smoke can be considered a safer technique for smoking of food. PMID:19056456

  10. Extending (Q)SARs to incorporate proprietary knowledge for regulatory purposes: A case study using aromatic amine mutagenicity.

    PubMed

    Ahlberg, Ernst; Amberg, Alexander; Beilke, Lisa D; Bower, David; Cross, Kevin P; Custer, Laura; Ford, Kevin A; Van Gompel, Jacky; Harvey, James; Honma, Masamitsu; Jolly, Robert; Joossens, Elisabeth; Kemper, Raymond A; Kenyon, Michelle; Kruhlak, Naomi; Kuhnke, Lara; Leavitt, Penny; Naven, Russell; Neilan, Claire; Quigley, Donald P; Shuey, Dana; Spirkl, Hans-Peter; Stavitskaya, Lidiya; Teasdale, Andrew; White, Angela; Wichard, Joerg; Zwickl, Craig; Myatt, Glenn J

    2016-06-01

    Statistical-based and expert rule-based models built using public domain mutagenicity knowledge and data are routinely used for computational (Q)SAR assessments of pharmaceutical impurities in line with the approach recommended in the ICH M7 guideline. Knowledge from proprietary corporate mutagenicity databases could be used to increase the predictive performance for selected chemical classes as well as expand the applicability domain of these (Q)SAR models. This paper outlines a mechanism for sharing knowledge without the release of proprietary data. Primary aromatic amine mutagenicity was selected as a case study because this chemical class is often encountered in pharmaceutical impurity analysis and mutagenicity of aromatic amines is currently difficult to predict. As part of this analysis, a series of aromatic amine substructures were defined and the number of mutagenic and non-mutagenic examples for each chemical substructure calculated across a series of public and proprietary mutagenicity databases. This information was pooled across all sources to identify structural classes that activate or deactivate aromatic amine mutagenicity. This structure activity knowledge, in combination with newly released primary aromatic amine data, was incorporated into Leadscope's expert rule-based and statistical-based (Q)SAR models where increased predictive performance was demonstrated. PMID:26879463

  11. Oxidation of aniline and other primary aromatic amines by manganese dioxide

    SciTech Connect

    Laha, S.; Luthy, R.G. )

    1990-03-01

    This investigation evaluated the redox reaction between a manganese dioxide, {sigma}-MnO{sub 2}, and anilines and other aromatic reductants in aqueous suspensions at pH values ranging from 3.7 to 6.5. The reaction with manganese dioxide may represent a pathway for transformation of aniline and other primary aromatic amines in acidic mineralogical and soil/water environments in the absence of oxygen and substantial microbial activity. The reaction rate with aniline is pH-dependent, increasing with decreasing pH, and first order with respect to {sigma}-MnO{sub 2} and organic solute. Aniline and p-toluidine are demonstrated to be 2-equiv reductants, as is believed to be the case for the other aromatic solutes considered in this study, including the substituted anilines, and hydroquinone and catechol and their alkyl substituents. Ring-bound nitrogen-containing aromatic solutes (methylimidazole, quinoline, and 5,5-dimethylhydantion) were unreactive with manganese dioxide at pH 6.4. The order of the reactivity of para-substituted anilines was methoxy >> methyl > chloro > carboxy >> nitro; the relative reactivity of these compounds correlated with the solute's half-wave potential and Hammett constant.

  12. Application of an ampholine-functionalized hybrid organic-inorganic silica material for the SPE of aromatic amines.

    PubMed

    Chen, Yihui; Wang, Tingting; Ma, Junfeng; Liang, Zhen; Chen, Mingliang; Fang, Jianghua; Gao, Haoqi; Zhang, Lihua; Zhang, Yukui

    2014-01-01

    An SPE cartridge based on an ampholine-functionalized hybrid organic-inorganic silica sorbent has been adopted for the analysis of aromatic amines including 4-aminobiphenyl, benzidine, 2-naphthylamine, p-chloroaniline, 2,4,5-trimethylaniline, and 3,3'-dichlorobenzidine. Crucial variables governing the extraction efficiency of the material such as the pH of sample, sample loading volume, solvent used for elution, and elution volume have been thoroughly optimized. The adsorption capacities for the six aromatic amines ranged from 0.17 to 1.82 μg/mg. The recoveries of aromatic amines spiked in textile samples ranged from 78.9 to 103.0%, with RSDs of 1.1-11.9% (n = 3). Moreover, the extraction efficiency of the ampholine-functionalized hybrid organic-inorganic silica sorbent was at least comparable with that of Oasis WCX. PMID:24178632

  13. Aromatic amine degradation in a UASB/CSTR sequential system treating Congo Red dye.

    PubMed

    Işik, Mustafa; Sponza, Delia Teresa

    2003-01-01

    In this study an anaerobic (upflow anaerobic sludge blanket reactor)/aerobic (completely stirred tank reactor) sequential system was used to treat a synthetic wastewater with minerals and co-substrate together with 100-4000 mg L(-1) of Congo Red dye (Direct red 28) (CR), which is a banned azo dye in Turkey. The effect of hydraulic retention time (HRT) on the decolorization and the COD removal efficiency was investigated at constant 100 mg L(-1) Congo Red concentration. 77% of COD and 95% of color was removed at a HRT of 0.486 days and a maximum organic loading rate of 6.656 kg COD m(-3) day(-1) in the anaerobic/aerobic stage. In the continuous operations, 88% of COD, 99% of color and 91% of total aromatic amine (TAA) were removed at a HRT of 3.60 days and at a CR concentration of 4000 mg L(-1). This corresponds to an organic loading rate of 1.81 kg COD m(-3) day(-1), and a CR dye loading rate of 46.37 g dye m(-3) h(-1), respectively, in the whole system. The TAA produced under anaerobic conditions was ultimately removed in the aerobic stage, resulting in very low aromatic amine recoveries (5-18%) in the last one. Therefore the aerobic effluents exhibited higher IC50 and specific methanogenic activities (SMA) compared to anaerobic and dye containing samples, indicating the reduced toxicity. PMID:14524683

  14. Bladder cancer mortality of workers exposed to aromatic amines: a 58-year follow-up.

    PubMed

    Pira, Enrico; Piolatto, Giorgio; Negri, Eva; Romano, Canzio; Boffetta, Paolo; Lipworth, Loren; McLaughlin, Joseph K; La Vecchia, Carlo

    2010-07-21

    We previously investigated bladder cancer risk in a cohort of dyestuff workers who were heavily exposed to aromatic amines from 1922 through 1972. We updated the follow-up by 14 years (through 2003) for 590 exposed workers to include more than 30 years of follow-up since last exposure to aromatic amines. Expected numbers of deaths from bladder cancer and other causes were computed by use of national mortality rates from 1951 to 1980 and regional mortality rates subsequently. There were 394 deaths, compared with 262.7 expected (standardized mortality ratio = 1.50, 95% confidence interval = 1.36 to 1.66). Overall, 56 deaths from bladder cancer were observed, compared with 3.4 expected (standardized mortality ratio = 16.5, 95% confidence interval = 12.4 to 21.4). The standardized mortality ratio for bladder cancer increased with younger age at first exposure and increasing duration of exposure. Although the standardized mortality ratio for bladder cancer steadily decreased with time since exposure stopped, the absolute risk remained approximately constant at 3.5 deaths per 1000 man-years up to 29 years after exposure stopped. Excess risk was apparent 30 years or more after last exposure. PMID:20548022

  15. Hemoglobin adducts of aromatic amines: associations with smoking status and type of tobacco.

    PubMed Central

    Bryant, M S; Vineis, P; Skipper, P L; Tannenbaum, S R

    1988-01-01

    Hemoglobin adducts of 15 aromatic amines were determined in nonsmokers and smokers of blond- or black-tobacco cigarettes living in Turin, Italy. The subjects were all males age 55 or less and were representative of the population previously examined in a case/control study of bladder cancer. 4-Aminobiphenyl adduct levels were found to be significantly different in the three groups, and the differences were approximately proportional to the relative risk of each group. Adjustment for age and cigarette consumption did not materially influence the differences. A significant correlation of adduct levels with cigarette consumption was also observed for all smokers as well as for smokers of blond tobacco. Other amines for which significant differences between smokers and nonsmokers were observed were 3-aminobiphenyl, 2-naphthylamine, o- and p-toluidine, 2,4-dimethylaniline, and 2-ethylaniline. Some of these amines are human bladder carcinogens, and their occurrence in blood as hemoglobin adducts is evidence for their metabolic activation. Thus, by a combination of traditional epidemiological methods and modern chemical analyses, we have provided evidence for a biochemical basis for the often observed association between cigarette smoking and bladder cancer. PMID:3200858

  16. Solvent-free functionalization of fullerene C60 and pristine multi-walled carbon nanotubes with aromatic amines

    NASA Astrophysics Data System (ADS)

    Ramírez-Calera, Itzel J.; Meza-Laguna, Victor; Gromovoy, Taras Yu.; Chávez-Uribe, Ma. Isabel; Basiuk, Vladimir A.; Basiuk, Elena V.

    2015-02-01

    We employed a direct one-step solvent-free covalent functionalization of solid fullerene C60 and pristine multi-walled carbon nanotubes (MWCNTs) with aromatic amines 1-aminopyrene (AP), 2-aminofluorene (AF) and 1,5-diaminonaphthalene (DAN). The reactions were carried out under moderate vacuum, in a wide temperature range of 180-250 °C, during relatively short time of about 2 h. To confirm successful amine attachment, a large number of analytical techniques were used (depending on the nanomaterial functionalized) such as Fourier transform infrared, Raman, X-ray photoelectron, 13C cross-polarization magic angle spinning NMR spectroscopy, thermogravimetric analysis, laser-desorption ionization time-of-flight mass spectrometry, temperature-programmed desorption with mass spectrometric detection, as well as scanning and transmission electron microscopy. The nucleophilic addition of the aromatic amines to C60 molecule was studied theoretically by using density functional theory (PBE GGA functional with Grimme dispersion correction in conjunction with the DNP basis set). In the case of crystalline C60, the solvent-free technique has a limited applicability due to poor diffusion of vaporous aromatic amines into the bulk. Nevertheless, the approach proposed allows for a facile preparation of aromatic amine-functionalized pristine MWCNTs without contamination with other chemical reagents, detergents and solvents, which is especially important for a vast variety of nanotube applications spanning from nanoelectronics to nanomedicine.

  17. Synergism of aromatic amines and benzo[a]pyrene in induction of Ah receptor-dependent genes.

    PubMed

    Borza, Alexandra; Plöttner, Sabine; Wolf, Alexander; Behm, Claudia; Selinski, Silvia; Hengstler, Jan G; Roos, Peter H; Bolt, Hermann M; Kuhlmann, Jürgen; Föllmann, Wolfram

    2008-12-01

    Aromatic amines have been shown to cause bladder cancer. However, epithelial cells of the urinary bladder, cells of origin of bladder cancer, may be exposed to numerous substances besides aromatic amines. In the present study, we analysed possible interactions between the aromatic amines 4-aminobiphenyl (4-ABP) as well as 2-naphthylamine (2-NA) and the polycyclic aromatic hydrocarbon benzo[a]pyrene (B[a]P). For this purpose we incubated primary porcine urinary bladder epithelial cells (PUBEC) with concentrations of 1 to 50 microM 4-ABP with and without co-exposure to B[a]P. As expected B[a]P increased mRNA expression of cytochrome P450 1A1 (CYP1A1), whereas 4-ABP had no effect. However, when co-exposed 4-ABP enhanced the induction of CYP1A1 by B[a]P. This result was confirmed by Western blot analysis of CYP1A1 protein expression. A similar effect as for CYP1A1 was also observed for cyclooxygenase-2 (COX-2) and UDP-glucuronosyltransferase 1 (UGT1). Next, we studied co-exposures of 2-NA and B[a]P. Similar as for 4-ABP also 2-NA enhanced B[a]P-mediated induction of CYP1A1. Our results demonstrate that some aromatic amines may enhance the influence of B[a]P on Ah receptor-dependent genes. PMID:18989657

  18. Co(II) PCP Pincer Complexes as Catalysts for the Alkylation of Aromatic Amines with Primary Alcohols.

    PubMed

    Mastalir, Matthias; Tomsu, Gerald; Pittenauer, Ernst; Allmaier, Günter; Kirchner, Karl

    2016-07-15

    Efficient alkylations of amines by alcohols catalyzed by well-defined Co(II) complexes are described that are stabilized by a PCP ligand (N,N'-bis(diisopropylphosphino)-N,N'-dimethyl-1,3-diaminobenzene) based on the 1,3-diaminobenzene scaffold. This reaction is an environmentally benign process implementing inexpensive, earth-abundant nonprecious metal catalysts and is based on the acceptorless alcohol dehydrogenation concept. A range of primary alcohols and aromatic amines were efficiently converted into mono-N-alkylated amines in good to excellent isolated yields. PMID:27356282

  19. Synthesis and crystal structure of a chiral aromatic amine chloride salt (C8H12N)Cl

    NASA Astrophysics Data System (ADS)

    Ben Salah, A. M.; Naїli, H.; Mhiri, T.; Bataille, T.

    2015-12-01

    The new organic chloride salt incorporating an aromatic primary amine with a chiral functional group, (S)-α-methylbenzylammonium), has been synthesized by slow evaporation method at room temperature. The crystals are trigonal with non-centrosymmetric sp. gr. R3. The crystal packing is determined by N-H···Cl hydrogen bonds and C-H···π interactions between the aromatic rings of the organic moieties, resulting in supramolecular architecture.

  20. Identification of non-regulated aromatic amines of toxicological concern which can be cleaved from azo dyes used in clothing textiles.

    PubMed

    Brüschweiler, Beat J; Küng, Simon; Bürgi, Daniel; Muralt, Lorenz; Nyfeler, Erich

    2014-07-01

    Azo dyes in textiles may release aromatic amines after enzymatic cleavage by skin bacteria or after dermal absorption and metabolism in the human body. From the 896 azo dyes with known chemical structure in the available textile dyes database, 426 azo dyes (48%) can generate one or more of the 22 regulated aromatic amines in the European Union in Annex XVII of REACH. Another 470 azo dyes (52%) can be cleaved into exclusively non-regulated aromatic amines. In this study, a search for publicly available toxicity data on non-regulated aromatic amines was performed. For a considerable percentage of non-regulated aromatic amines, the toxicity database was found to be insufficient or non-existent. 62 non-regulated aromatic amines with available toxicity data were prioritized by expert judgment with objective criteria according to their potential for carcinogenicity, genotoxicity, and/or skin sensitization. To investigate the occurrence of azo dye cleavage products, 153 random samples of clothing textiles were taken from Swiss retail outlets and analyzed for 22 high priority non-regulated aromatic amines of toxicological concern. Eight of these 22 non-regulated aromatic amines of concern could be detected in 17% of the textile samples. In 9% of the samples, one or more of the aromatic amines of concern could be detected in concentrations >30 mg/kg, in 8% of the samples between 5 and 30 mg/kg. The highest measured concentration was 622 mg/kg textile. There is an obvious need to assess consumer health risks for these non-regulated aromatic amines and to fill this gap in the regulation of clothing textiles. PMID:24793261

  1. CATABOLISM OF AROMATIC BIOGENIC AMINES BY 'PSEUDOMONAS AERUGINOSA' PA01 VIA META CLEAVAGE OF HOMOPROTOCATECHUIC ACID (JOURNAL VERSION)

    EPA Science Inventory

    Pseudomonas aruginosa PA01 catabolized the aromatic amines tyramine and octopamine through 4-hydroxyphenylacetic acid and 3,4-dihydroxyphenylacetic acid (HPA). Meta ring cleavage was mediated by 3-4-dihydroxyphenylacetate 2,3-dioxygenase (HPADO), producing 2-hydroxy-5-carboxymeth...

  2. Enantioselective ring-opening of meso-epoxides by aromatic amines catalyzed by a homochiral metal-organic framework.

    PubMed

    Regati, Sridhar; He, Yabing; Thimmaiah, Muralidhara; Li, Peng; Xiang, Shengchang; Chen, Banglin; Zhao, John Cong-Gui

    2013-10-28

    The enantioselective ring-opening of meso-epoxides by aromatic amines was achieved by using a new chiral metal-organic framework . The corresponding α-hydroxyamines were obtained with good yields and ee values (up to 89% ee). PMID:24030658

  3. SEDIMENT-MEDIATED REDUCTION OF 2,4,6-TRINITROTOLUENE AND FATE OF THE RESULTING AROMATIC (POLY)AMINES

    EPA Science Inventory

    2,4,6-Trinitrotoluene is a major surface and subsurface contaminant found at numerous munitions production and storage facilities. The reductive transformation of 2,4,6-trinitrotoluene (TNT) to aromatic (poly)amines and the consequent fate of these products were studied in anaer...

  4. Development and validation of a hydrophilic interaction liquid chromatographic method for determination of aromatic amines in environmental water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A simple, precise, and accurate hydrophilic interaction liquid chromatographic (HILIC) method has been developed for the determination of 5 aromatic amines in environmental water samples. Chromatography was carried out on a bare silica column, using a mixture of acetonitrile: phosphate buffer (10 mM...

  5. Structural Analysis of Aliphatic vs. Aromatic Substrate Specificity in a Copper Amine Oxidase from Hansenula polymorpha†,‡

    PubMed Central

    Klema, Valerie J.; Solheid, Corinne J.; Klinman, Judith P.; Wilmot, Carrie M.

    2013-01-01

    Copper amine oxidases (CAOs) are responsible for the oxidative deamination of primary amines to their corresponding aldehydes. The CAO catalytic mechanism can be divided into two half-reactions: a reductive half-reaction, in which a primary amine substrate is oxidized to its corresponding aldehyde with the concomitant reduction of the organic cofactor 2,4,5-trihydroxyphenylalanine quinone (TPQ), and an oxidative half-reaction, in which reduced TPQ is re-oxidized with the reduction of molecular oxygen to hydrogen peroxide. The reductive half-reaction proceeds via Schiff base chemistry, in which the primary amine substrate first attacks the C5 carbonyl of TPQ, forming a series of covalent Schiff base intermediates. The X-ray crystal structures of copper amine oxidase-1 from the yeast Hansenula polymorpha (HPAO-1) in complex with ethylamine and benzylamine have been solved to resolutions of 2.18 and 2.25 Å, respectively. These structures reveal the two amine substrates bound at the back of the active site coincident with TPQ in its two-electron reduced aminoquinol form. Rearrangements of particular amino acid side chains within the substrate channel and specific protein-substrate interactions provide insight into substrate specificity in HPAO-1. These changes begin to account for this CAO’s kinetic preference for small, aliphatic amines over the aromatic amines or whole peptides preferred by some of its homologs. PMID:23452079

  6. Using spin labels to study molecular processes in soils: Covalent binding of aromatic amines to humic acids of soils

    NASA Astrophysics Data System (ADS)

    Aleksandrova, O. N.; Kholodov, V. A.; Perminova, I. V.

    2015-08-01

    Interactions of aliphatic and aromatic amines with soil and humic acids isolated from it are studied by means of spin labels and electron paramagnetic resonance (EPR) spectroscopy. Nitroxyl radicals containing amino groups are used as spin labels. It is found experimentally that aromatic amines are instantaneously converted to the bound state. It is shown that the microareas of their incorporation are characterized by a significant delay in the reduction of the nitroxyl fragment of spin-label molecules, indicating the formation of condensed structures typical of an oxidative binding mechanism. It is concluded that aliphatic amines do not bind to humic acids. It is noted that the studied process allows elucidating the formation of bound xenobiotic residues in soils.

  7. Selective Release of Aromatic Heterocycles from Ruthenium Tris(2-pyridylmethyl)amine with Visible Light

    PubMed Central

    Li, Ao; White, Jessica K.; Arora, Karan; Herroon, Mackenzie K.; Martin, Philip D.; Schlegel, H. Bernhard; Podgorski, Izabela; Turro, Claudia; Kodanko, Jeremy J.

    2016-01-01

    Three complexes of the general formula [Ru(TPA)L2](PF6)2 [TPA = tris(2-pyridylmethyl)amine], where L = pyridine (1), nicotinamide (2), and imidazole (3), were prepared and characterized spectroscopically. X-ray crystallographic data were obtained for 1 and 3. Complexes 1–3 show strong absorption in the visible region and selective release of heterocycles upon irradiation with visible light. Time-dependent density functional theory calculations are consistent with the presence of singlet metal-to-ligand charge-transfer bands in the visible region in 1–3. Caged heterocycles 1–3 are highly stable in solution in the dark, including in cell growth media. Cell viability data show no signs of toxicity of 1–3 against PC-3 cells at concentrations up to 100 μM under light and dark conditions, consistent with Ru(TPA) acting as a nontoxic and effective photocaging group for aromatic heterocycles. PMID:26670781

  8. Relation between crust development and heterocyclic aromatic amine formation when air-roasting a meat cylinder.

    PubMed

    Kondjoyan, Alain; Chevolleau, Sylvie; Portanguen, Stéphane; Molina, Jérôme; Ikonic, Predrag; Clerjon, Sylvie; Debrauwer, Laurent

    2016-12-15

    The meat crust that develops during cooking is desired by consumers for its organoleptic properties, but it is also where heterocyclic aromatic amines (HAs) are formed. Here we measured HAs formation during the development of a colored crust on the surface of a beef meat piece. HAs formation was lower in the crust than previously measured in meat slices subjected to the same air jet conditions. This difference is explained by a lower average temperature in the colored crust than in the meat slices. Temperature effects can also explain why colored crust failed to reproduce the plateauing and decrease in HAs content observed in meat slices. We observed a decrease in creatine content from the center of the meat piece to the crust area. In terms of the implications for practice, specific heating conditions can be found to maintain a roast beef meat aspect while dramatically reducing HAs content. PMID:27451229

  9. Selective iridium-catalyzed alkylation of (hetero)aromatic amines and diamines with alcohols under mild reaction conditions.

    PubMed

    Blank, Benoît; Michlik, Stefan; Kempe, Rhett

    2009-01-01

    A P,N-ligand-coordinated iridium complex has been employed as an efficient catalyst for the selective monoalkylation of (hetero)aromatic amines with alcohols. A significant improvement of this alkylation method has been achieved, such that it can be performed at a temperature of 70 degrees C and with catalyst loadings as low as 0.1 mol % Ir, while still affording excellent yields of secondary amines. Furthermore, the high selectivity of this catalyst for the monoalkylation of aromatic amino functions has been successfully exploited for the alkylation of diamines in both symmetric and nonsymmetric fashions, providing a novel and very efficient synthetic tool for the preparation of N,N'-dialkylated aromatic diamines. PMID:19219878

  10. Copper-Catalyzed Aza-Michael Addition of Aromatic Amines or Aromatic Aza-Heterocycles to α,β-Unsaturated Olefins.

    PubMed

    Kim, Seongcheol; Kang, Seongil; Kim, Gihyeon; Lee, Yunmi

    2016-05-20

    A highly efficient and mild Cu-catalyzed conjugate addition reaction of aromatic amines and aromatic aza-heterocycles to α,β-unsaturated olefins is described. The transformation is promoted by 3-7 mol % of a Cu complex generated in situ from a mixture of inexpensive CuCl, a readily available phosphine or imidazolium salt, and KOt-Bu at ambient temperature. A wide range of β-amino sulfone, β-amino nitrile, and β-amino carbonyl compounds is efficiently and selectively synthesized in high yields (62-99%). PMID:27080327

  11. π(+)-π interactions between (hetero)aromatic amine cations and the graphitic surfaces of pyrogenic carbonaceous materials.

    PubMed

    Xiao, Feng; Pignatello, Joseph J

    2015-01-20

    Many organic compounds of environmental concern contain amine groups that are positively charged at environmental pH. Here we present evidence that (hetero)aromatic amine cations can act as π acceptors in forming π(+)–π electron donor–acceptor (EDA) interactions with the π electron-rich, polyaromatic surface of pyrogenic carbonaceous materials (PCMs) (i.e., biochar, black carbon, and graphene). The π(+)–π EDA interactions combine a cation−π force with a π–π EDA force resulting from charge polarization of the ring’s quadrupole. Adsorption on a biochar and reference adsorbent graphite was conducted of triazine herbicides, substituted anilines, heterocyclic aromatic amines, and other amines whose charge is insulated from the aromatic ring. When normalized for the hydrophobic effect, the adsorption increased with decreasing pH as the amines became ionized, even on graphite that had no significant fixed or variable charge. The cationic π acceptor (quinolinium ion) was competitively displaced more effectively by the π acceptor 2,4-dinitrobenzene than by the π donor naphthalene. The maximum electrostatic potential of organocations computed with density functional theory was found to be a strong predictor of the π(+)–π EDA interaction. The π(+)–π EDA interaction was disfavored by electropositive alkyl substituents and by charge delocalization into additional rings. Amines whose charge was insulated from the ring fell far out of the correlation (more positive free energy of adsorption). Identifying and characterizing this novel π(+)–π EDA interaction on PCMs will help in predicting the fate of organocations in both natural and engineered systems. PMID:25569811

  12. Theoretical studies of chemical reactivity of metabolically activated forms of aromatic amines toward DNA.

    PubMed

    Shamovsky, Igor; Ripa, Lena; Blomberg, Niklas; Eriksson, Leif A; Hansen, Peter; Mee, Christine; Tyrchan, Christian; O'Donovan, Mike; Sjö, Peter

    2012-10-15

    The metabolism of aromatic and heteroaromatic amines (ArNH₂) results in nitrenium ions (ArNH⁺) that modify nucleobases of DNA, primarily deoxyguanosine (dG), by forming dG-C8 adducts. The activated amine nitrogen in ArNH⁺ reacts with the C8 of dG, which gives rise to mutations in DNA. For the most mutagenic ArNH₂, including the majority of known genotoxic carcinogens, the stability of ArNH⁺ is of intermediate magnitude. To understand the origin of this observation as well as the specificity of reactions of ArNH⁺ with guanines in DNA, we investigated the chemical reactivity of the metabolically activated forms of ArNH₂, that is, ArNHOH and ArNHOAc, toward 9-methylguanine by DFT calculations. The chemical reactivity of these forms is determined by the rate constants of two consecutive reactions leading to cationic guanine intermediates. The formation of ArNH⁺ accelerates with resonance stabilization of ArNH⁺, whereas the formed ArNH⁺ reacts with guanine derivatives with the constant diffusion-limited rate until the reaction slows down when ArNH⁺ is about 20 kcal/mol more stable than PhNH⁺. At this point, ArNHOH and ArNHOAc show maximum reactivity. The lowest activation energy of the reaction of ArNH⁺ with 9-methylguanine corresponds to the charge-transfer π-stacked transition state (π-TS) that leads to the direct formation of the C8 intermediate. The predicted activation barriers of this reaction match the observed absolute rate constants for a number of ArNH⁺. We demonstrate that the mutagenic potency of ArNH₂ correlates with the rate of formation and the chemical reactivity of the metabolically activated forms toward the C8 atom of dG. On the basis of geometric consideration of the π-TS complex made of genotoxic compounds with long aromatic systems, we propose that precovalent intercalation in DNA is not an essential step in the genotoxicity pathway of ArNH₂. The mechanism-based reasoning suggests rational design strategies to

  13. Synthesis of highly luminescent cobalt(ii)-bis(8-hydroxyquinoline) nanosheets as isomeric aromatic amine probes

    NASA Astrophysics Data System (ADS)

    Li, Haibing; Li, Yuling

    2009-09-01

    Highly luminescent and water-soluble cobalt(ii)-bis(8-hydroxyquinoline) (CoQ2) nanosheets have been successfully synthesized via a simple, rapid sonochemical method. The water-soluble CoQ2 nanosheets were characterized by luminescence spectroscopy, UV-vis spectroscopy, FT-IR spectroscopy and transmission electron microscopy (TEM). The CoQ2 nanosheets allow highly sensitive and selective determination of p-nitroaniline via fluorescence quenching. Under optimal conditions, the relative fluorescence intensities of nanosheets decreased linearly with increasing p-nitroaniline. However, the sensitivity of CoQ2 nanosheets toward other aromatic amines including o-diaminobenzene, m-diaminobenzene, p-diaminobenzene, p-toluidine, o-nitroaniline, m-nitroaniline, p-chloroaniline and aniline is negligible. It is found that p-nitroaniline can quench the luminescence of CoQ2 nanosheets in a concentration-dependent manner that is best described by a Stern-Volmer-type equation. The possible underlying mechanism is discussed.Highly luminescent and water-soluble cobalt(ii)-bis(8-hydroxyquinoline) (CoQ2) nanosheets have been successfully synthesized via a simple, rapid sonochemical method. The water-soluble CoQ2 nanosheets were characterized by luminescence spectroscopy, UV-vis spectroscopy, FT-IR spectroscopy and transmission electron microscopy (TEM). The CoQ2 nanosheets allow highly sensitive and selective determination of p-nitroaniline via fluorescence quenching. Under optimal conditions, the relative fluorescence intensities of nanosheets decreased linearly with increasing p-nitroaniline. However, the sensitivity of CoQ2 nanosheets toward other aromatic amines including o-diaminobenzene, m-diaminobenzene, p-diaminobenzene, p-toluidine, o-nitroaniline, m-nitroaniline, p-chloroaniline and aniline is negligible. It is found that p-nitroaniline can quench the luminescence of CoQ2 nanosheets in a concentration-dependent manner that is best described by a Stern-Volmer-type equation

  14. DNA Adduct Formation of 4-Aminobiphenyl and Heterocyclic Aromatic Amines in Human Hepatocytes

    PubMed Central

    Nauwelaers, Gwendoline; Bessette, Erin E.; Gu, Dan; Tang, Yijin; Rageul, Julie; Fessard, Valérie; Yuan, Jian-Min; Yu, Mimi C.; Langouët, Sophie; Turesky, Robert J.

    2011-01-01

    DNA adduct formation of the aromatic amine, 4-aminobiphenyl (4-ABP), a known human carcinogen present in tobacco smoke, and the heterocyclic aromatic amines (HAAs), 2-amino-9H-pyrido[2,3-b]indole (AαC), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), and 2-amino-3,8-dimethylmidazo[4,5-f]quinoxaline (MeIQx), potential human carcinogens, which are also present in tobacco smoke or formed during the high-temperature cooking of meats, was investigated in freshly cultured human hepatocytes. The carcinogens (10 μM) were incubated with hepatocytes derived from eight different donors for time periods up to 24 h. The DNA adducts were quantified by liquid chromatography-electrospray ionization mass spectrometry with a linear quadrupole ion trap mass spectrometer. The principal DNA adducts formed for all of the carcinogens were N-(deoxyguanosin-8-yl) (dG-C8) adducts. The levels of adducts ranged from 3.4 to 140 adducts per 107 DNA bases. The highest level of adduct formation occurred with AαC, followed by 4-ABP, then by PhIP, MeIQx, and IQ. Human hepatocytes formed dG-C8-HAA-adducts at levels that were up to 100-fold greater than the amounts of adducts produced in rat hepatocytes. In contrast to HAA adducts, the levels of dG-C8-4-ABP adduct formation were similar in human and rat hepatocytes. These DNA binding data demonstrate that the rat, an animal model that is used for carcinogenesis bioassays, significantly underestimates the potential hepatic genotoxicity of HAAs in humans. The high level of DNA adducts formed by AαC, a carcinogen produced in tobacco smoke at levels that are up to 100-fold higher than the amounts of 4-ABP, is noteworthy. The possible causal role of AαC in tobacco-associated cancers warrants investigation. PMID:21456541

  15. Distribution of two triamines, spermidine and homospermidine, and an aromatic amine, 2-phenylethylamine, within the phylum Bacteroidetes.

    PubMed

    Hosoya, Ryuichi; Hamana, Koei

    2004-10-01

    Cellular polyamines of the newly additional 19 species belonging to the class Bacteroides of the phylum Bacteroidetes were analyzed by HPLC to display polyamine distribution as a chemotaxonomic marker within the total 41 species. Three profiles, the presence of spermidine, the presence of homospermidine and the absence of both triamines, corresponded to their phylogenetical positions within the four families of the class. The occurrence of an aromatic amine, 2-phenylethylamine, extracted into cellular polyamine fraction, was also determined within the 121 species distributed within the phylum. This aromatic amine was found in Cellulophaga lytica, Cytophaga latercula, Tenacibaculum amylolyticum, Tenacibaculum martimum, Tenacibaculum mesophilum and Psychroflexus torquis belonging to the family Flavobacteriaceae of the class Flavobacteria, and Flexibacter flexilis and Microscilla marina belonging to the family Flexibacteraceae of the class Sphingobacteria. PMID:15747230

  16. Concise synthesis of 2-amino-4(3H)-quinazolinones from simple (Hetero)aromatic amines.

    PubMed

    Zeghida, Walid; Debray, Julien; Chierici, Sabine; Dumy, Pascal; Demeunynck, Martine

    2008-03-21

    A novel and simple method of preparation of 2-alkylaminoquinazolin-4-ones with fused heteroaromatic rings from easily accessible (hetero)aromatic amines is described. The method is very efficient, and the 2-alkylaminoquinazolinone derivatives are obtained in three steps without chromatographic purification. The key step is the ring closure of the N-protected guanidine intermediates by intramolecular Friedel-Craft's type substitution. PMID:18290665

  17. Conformational switching of ethano-bridged Cu,H2-bis-porphyrin induced by aromatic amines

    PubMed Central

    Maglie, Emanuela; Pagano, Rosanna; Borovkov, Victor; Inoue, Yoshihisa; Valli, Ludovico; Giancane, Gabriele

    2015-01-01

    Summary Cu,H2-bis-porphyrin (Cu,H2-Por2), in which copper porphyrin and free-base porphyrin are linked together by an ethano-bridge, was dissolved in chloroform and spread at the air/liquid subphase interface of a Langmuir trough. The bis-porphyrin derivative, floating film was characterized by reflection spectroscopy and the surface pressure of the floating film was studied as a function of the mean area per molecule. When aromatic amines are dissolved in the subphase, an evident interaction between the bis-porphyrin host and the aromatic amine guest is observed. A clear-cut variation of the profile of surface pressure vs area per molecule curve is observed. Reflection spectroscopy highlights that the aromatic amines dissolved in the subphase are able to induce the syn-to-anti conformational switching in the bis-porphyrin derivative. The Langmuir–Schaefer technique has been used to transfer the floating bis-porphyrin film (when using pure water as a subphase) to a surface plasmon resonance (SPR) substrate and the resulting device was able to detect the presence of aniline at concentrations as low as 1 nM in aqueous solution. The high selectivity of the SPR sensing device has been verified by checking the spectral response of the active layer towards other analytes dissolved in the aqueous solutions. PMID:26665088

  18. Conformational switching of ethano-bridged Cu,H2-bis-porphyrin induced by aromatic amines.

    PubMed

    Bettini, Simona; Maglie, Emanuela; Pagano, Rosanna; Borovkov, Victor; Inoue, Yoshihisa; Valli, Ludovico; Giancane, Gabriele

    2015-01-01

    Cu,H2-bis-porphyrin (Cu,H2-Por2), in which copper porphyrin and free-base porphyrin are linked together by an ethano-bridge, was dissolved in chloroform and spread at the air/liquid subphase interface of a Langmuir trough. The bis-porphyrin derivative, floating film was characterized by reflection spectroscopy and the surface pressure of the floating film was studied as a function of the mean area per molecule. When aromatic amines are dissolved in the subphase, an evident interaction between the bis-porphyrin host and the aromatic amine guest is observed. A clear-cut variation of the profile of surface pressure vs area per molecule curve is observed. Reflection spectroscopy highlights that the aromatic amines dissolved in the subphase are able to induce the syn-to-anti conformational switching in the bis-porphyrin derivative. The Langmuir-Schaefer technique has been used to transfer the floating bis-porphyrin film (when using pure water as a subphase) to a surface plasmon resonance (SPR) substrate and the resulting device was able to detect the presence of aniline at concentrations as low as 1 nM in aqueous solution. The high selectivity of the SPR sensing device has been verified by checking the spectral response of the active layer towards other analytes dissolved in the aqueous solutions. PMID:26665088

  19. Removal of phenols and aromatic amines from wastewater by a combination treatment with tyrosinase and a coagulant

    SciTech Connect

    Wada, Shinji; Ichikawa, Hiroyasu; Tatsumi, Kenji )

    1995-02-20

    Removal of phenols and aromatic amines from industrial wastewater by tyrosinase was investigated. A color change from colorless to dark brown was observed, but no precipitate was formed. Colored products were found to be easily removed by a combination treatment with tyrosinase and a cationic polymer coagulant containing amino group, such as hexamethylenediamine-epichlorohidrin polycondensate, polyethleneimine, or chitosan. The first two coagulants, synthetic polymers, were more effective than chitosan, a polymer produced in crustacean shells. Phenols and aromatic amines are not precipitated by any kind of coagulants, but their enzymatic reaction products are easily precipitated by a cationic polymer coagulant. These results indicate that the combination of tyrosinase and a cationic polymer coagulant is effective in removing carcinogenic phenols and aromatic amines from an aqueous solution. Immobilization of tyrosinase on magnetite gave a good retention of activity (80%) and storage stability i.e., only 5% loss after 15 days of storage at ambient temperature. In the treatment of immobilized tyrosinase, colored enzymatic reaction products were removed by less coagulant compared with soluble tyrosinase.

  20. Effect of thermal treatment on meat proteins with special reference to heterocyclic aromatic amines (HAAs).

    PubMed

    Shabbir, Muhammad Asim; Raza, Ali; Anjum, Faqir Muhammad; Khan, Moazzam Rafiq; Suleria, Hafiz Ansar Rasul

    2015-01-01

    Meat is one of the most imperative protein sources available with respect to its production and consumption. It is the richest source of some valuable nutrients like proteins, essential amino acids, polyunsaturated fatty acids, vitamins, and minerals like iron, zinc, and selenium. Thermal treatment produces conformational changes in protein structure as well as flavor, texture, and appearance, and chemical properties of the ingredients are also changed. Heterocyclic aromatic amines (HAAs), potent mutagens/carcinogens, are formed during the cooking of meat at high temperature. The review paper highlights the effects of various cooking methods, i.e., pan-frying, deep-frying, charcoal grilling, and roasting, on the formation of HAAs. The levels of HAAs produced in cooked meats vary depending upon the cooking method, time of cooking, and the type of meat being cooked. Metabolic behavior of HAAs is very unique, they interfere in the activity of many enzymes, modify the metabolic pathways, and lead to the adduct formation of DNA. The application of black pepper and several other spices during processing may reduce the formation of these (HAAs) mutagenic compounds. PMID:24915407

  1. Biotransformation of Trichoderma spp. and Their Tolerance to Aromatic Amines, a Major Class of Pollutants

    PubMed Central

    Cocaign, Angélique; Bui, Linh-Chi; Silar, Philippe; Chan Ho Tong, Laetitia; Busi, Florent; Lamouri, Aazdine; Mougin, Christian; Rodrigues-Lima, Fernando

    2013-01-01

    Trichoderma spp. are cosmopolitan soil fungi that are highly resistant to many toxic compounds. Here, we show that Trichoderma virens and T. reesei are tolerant to aromatic amines (AA), a major class of pollutants including the highly toxic pesticide residue 3,4-dichloroaniline (3,4-DCA). In a previous study, we provided proof-of-concept remediation experiments in which another soil fungus, Podospora anserina, detoxifies 3,4-DCA through its arylamine N-acetyltransferase (NAT), a xenobiotic-metabolizing enzyme that enables acetyl coenzyme A-dependent detoxification of AA. To assess whether the N-acetylation pathway enables AA tolerance in Trichoderma spp., we cloned and characterized NATs from T. virens and T. reesei. We characterized recombinant enzymes by determining their catalytic efficiencies toward several toxic AA. Through a complementary approach, we also demonstrate that both Trichoderma species efficiently metabolize 3,4-DCA. Finally, we provide evidence that NAT-independent transformation is solely (in T. virens) or mainly (in T. reesei) responsible for the observed removal of 3,4-DCA. We conclude that T. virens and, to a lesser extent, T. reesei likely utilize another, unidentified, metabolic pathway for the detoxification of AA aside from acetylation. This is the first molecular and functional characterization of AA biotransformation in Trichoderma spp. Given the potential of Trichoderma for cleanup of contaminated soils, these results reveal new possibilities in the fungal remediation of AA-contaminated soil. PMID:23728813

  2. Survey of Primary Aromatic Amines and Colorants in Polyurethane, Nylon and Textile Toys.

    PubMed

    Abe, Yutaka; Yamaguchi, Miku; Mutsuga, Motoh; Akiyama, Hiroshi; Kawamura, Yoko

    2016-01-01

    The residual and migration levels of 28 primary aromatic amines (PAAs) in polyurethane and nylon toys were determined using LC-MS/MS, and the migration and residual amounts of PAAs and 15 colorants in textile toys were determined using LC-MS/MS and LC-TOF-MS according to the European Standard EN71. Among 34 polyurethane toy samples, 2,6-diaminotoluene and 2,4-diaminotoluene were detected in the same 12 samples at residual levels ranging from 2.1 to 19.7 and from 7.6 to 39.6 μg/g, respectively. Furthermore, 4,4'-diaminodiphenylmethane (4,4'-MDA) and aniline were detected in 9 samples (from 0.2 to 8.7 μg/g), and one sample (0.4 μg/g), respectively. PAAs were not detected in the 8 samples of nylon toys. As for the migration test into water, only 4,4'-MDA migrated from 3 polyurethane toys at levels ranging from 0.4 to 2.5 μg/g. PAAs did not migrate from the 43 textile toys, but colorants such as Solvent Yellow 1 and Basic Red 9 were detected at the residual level of 0.02 μg/g. The residual levels of PAAs and colorants detected in this study were significantly lower than the limit values established by the European Union regulation. PMID:27211915

  3. Hydrogenation of nitroarenes into aromatic amines over Ag@BCN colloidal catalysts.

    PubMed

    Qiu, Xiaoqing; Liu, Qiuwen; Song, MingXia; Huang, Caijin

    2016-09-01

    The present work reports that two-dimension layered ternary boron carbon nitrogen nanosheets can serve as good carriers to support and disperse noble metal nanoparticles. The Ag@BCN colloids have thus been prepared by attaching Ag nanoparticles on the surfaces of BCN nanosheets. The detailed structures of the Ag@BCN samples were investigated by X-ray diffraction, transmission electron microscopy, atomic force microscope, infrared, and X-ray photoelectron spectroscopy. It is found that the surface NH groups of BCN nanosheets are beneficial for the attachment of Ag nanopaprticles. Compared with the conventional organic capping compounds, the two dimensional planar BCN nanosheets endow the attached nanoparticle with the high active surfaces. Moreover, the hydrogenation of nitroarenes into the corresponding aromatic amines can be highly achieved over Ag@BCN colloids by NaBH4. In particular, the apparent activation energy of the conversion reaction of p-nitroaniline to p-phenylenediamine was found to be 76.0kJ/mol over the Ag@BCN colloids with 3wt% Ag content. Our results may provide a new approach for the design noble metal based composites and find the practical application for the hydrogenation of nitroarenes. PMID:27254255

  4. Sapindus mukorossi mediated green synthesis of some manganese oxide nanoparticles interaction with aromatic amines

    NASA Astrophysics Data System (ADS)

    Jassal, Vidhisha; Shanker, Uma; Gahlot, Sweta; Kaith, B. S.; Kamaluddin; Iqubal, Md Asif; Samuel, Pankaj

    2016-04-01

    A green route was successfully used to synthesize some manganese oxides (MO) nanoparticles like MnO2, Mn2O3 and Mn3O4 with varied Mn/O ratio. This approach involved utilization of Sapindus mukorossi (raw reetha)-water as a natural surfactant-solvent system. The most important feature of present work was that during the synthesis of nanoparticles, no harmful toxic solvent or chemicals were used in order to follow the principles of green chemistry. The size of nanoparticles was recorded below 100 nm with different shapes and morphologies. MnO2 nanoparticles were found to have needle shape, Mn2O3: spherical and Mn3O4: cubic shape. The synthesized nanoparticles were characterized by powder X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The synthesized MO nanoparticles were found to act as a solid support cum catalysts for the oxidation and polymerization of some aromatic amines like p-anisidine, p-toluidine, p-chloroaniline and aniline.

  5. Aromatic amine contents, component distributions and risk assessment in sludge from 10 textile-dyeing plants.

    PubMed

    Ning, Xun-An; Liang, Jie-Ying; Li, Rui-Jing; Hong, Zhen; Wang, Yu-Jie; Chang, Ken-Lin; Zhang, Ya-Ping; Yang, Zuo-Yi

    2015-09-01

    Aromatic amines (AAs), which are components of synthetic dyes, are recalcitrant to the wastewater treatment process and can accumulate in sludge produced by textile-dyeing, which may pose a threat to the environment. A comprehensive investigation of 10 textile-dyeing plants was undertaken in Guangdong Province in China. The contents and component distributions of AAs were evaluated in this study, and a risk assessment was performed. The total concentrations of 14 AAs (Σ14 AAs) varied from 11 μg g(-1)dw to 82.5 μg g(-1)dw, with a mean value of 25 μg g(-1)dw. The component distributions of AAs were characterized by monocyclic anilines, of which 2-methoxy-5-methylaniline and 5-nitro-o-toluidine were the most dominant components. The risk quotient (RQ) value was used to numerically evaluate the ecological risk of 14 AAs in the environment. The result showed that the 14 AAs contents in textile-dyeing sludge may pose a high risk to the soil ecosystem after being discarded on soil or in a landfill. PMID:25973862

  6. Sandwich-type polyoxotungstate hybrids decorated by nickel-aromatic amine complexes

    SciTech Connect

    Ma Pengtao; Zhao Junwei; Wang Jingping; Shen Yue; Niu Jingyang

    2010-01-15

    Three new sandwich-type polyoxotungstates (POTs) decorated by nickel-2,2'-bpy complexes [{l_brace}Ni(2,2'-bpy){sub 2}(H{sub 2}O){r_brace}{sub 2}{l_brace}Ni(2,2'-bpy){r_brace}{sub 2} {l_brace}Ni{sub 4}(H{sub 2}O){sub 2}(B-alpha-XW{sub 9}O{sub 34}){sub 2}{r_brace}]{sup n-} (X=P{sup V}, n=4 for 1; X=As{sup V}, n=4 for 2; X=Ge{sup IV}, n=4 for 3) (2,2'-bpy=2,2'-bipyridine) were successfully synthesized under hydrothermal conditions and structurally characterized by elemental analyses, IR spectroscopy, single-crystal X-ray diffraction, and magnetic properties. Single-crystal structural analyses indicate that 1 and 2 are isostructural and both crystallize in the monoclinic space group C2/c, whereas 3 belongs to the triclinic space group P1-bar. To our knowledge, 1, 2 and 3 represent rare examples of the organic-inorganic hybrid sandwich-type polyoxometalates functionalized by multiple nickel-aromatic amine complexes. Magnetic measurements of 1 exhibit the presence of ferromagnetic interactions within the rhombic tetranuclear-Ni{sup II} cluster. - Graphical abstract: Three new sandwich-type polyoxotungstates (POTs) decorated by nickel-2,2'-bpy complexes were successfully synthesized under hydrothermal conditions and structurally characterized.

  7. N-acetylation of aromatic amines: implication for skin and immune cells.

    PubMed

    Bonifas, Jutta; Blomeke, Brunhilde

    2015-01-01

    Frequently, aromatic amine (AA) contact to the skin occurs via occupational or 'life style' exposure to hair dye intermediates and couplers, usually monocyclic p-phenylenediamines and meta-substituted aminophenols. The transport of AA from the outer surface to the systemic circulation predominantly follows the intracellular route. Skin tends to have relatively higher phase II compared to phase I xenobiotic metabolizing enzyme capacity, and levels are generally regarded as lower than those in liver. Inside skin cells AA are primarily N-acetylated and detoxified by N-acetyltransferase 1. AA activation via hydroxylation or chemical oxidation competes with acetylation and is only of importance under circumstances when N-acetylation capacities are limited. The reactive AA derivatives are able to elicit effects by virtue of their modifications of skin proteins resulting in irritant or allergic contact dermatitis. Overall, the effective acetylation of topically applied AAs in skin cells emphasizes a protective role of cutaneous acetylation mediating a classical "first-pass" effect, which attenuates systemic exposure. PMID:25553379

  8. Preparation of monodispersed vinylpyridine-divinylbenzene porous copolymer resins and their application to high-performance liquid chromatographic separation of aromatic amines.

    PubMed

    Kitahara, Kei-Ichi; Okuya, Shuji; Yoshihama, Isao; Hanada, Takako; Nagashima, Kunio; Arai, Sadao

    2009-10-30

    For the separation of aromatic amines, two types of monodispersed porous polymer resins were prepared by the copolymerization of 2-vinylpyridine and 4-vinylpyridine with divinylbenzene in the presence of template silica gel particles (particle size 5 microm), followed by dissolution of the template silica gel in an alkaline solution. The transmission electron micrographs and the scanning electron micrograph revealed that these templated polymer resins have a spherical morphology with a good monodispersity and porous structure. Using these monodispersed polymer resins, the high-performance liquid chromatographic separation of aromatic amines in the mobile phases of pHs 2.0, 2.9, 4.1, 7.2 and 11.7 were carried out. The 2-vinylpyridine-divinylbenzene copolymer resins showed slightly stronger retentions for aromatic amines than the 4-vinylpyridine-divinylbenzene copolymer resins. Under acidic conditions (around pH 2.0), aniline and the toluidines showed no retention on these copolymer resins due to the repulsion between the cationic forms of these amines and pyridinium cations in the stationary phase, whereas less basic aromatic amines or non-basic acetanilide showed slight retentions. Above pH 4.1, the separation of aromatic amines with these polymer resins showed a typical reversed-phase mode separation. Therefore, the separation patterns of aromatic amines are effectively tunable by changing the pH value of the mobile phases. A good separation of eight aromatic amines was achieved at pH 2.9 using the 2-vinylpyridine-divinylbenzene copolymer resins. PMID:19442983

  9. Comments on the history and importance of aromatic and heterocyclic amines in public health.

    PubMed

    Weisburger, John H

    2002-09-30

    The carcinogenic risk of aromatic amines in humans was first discovered when a physician related the occurrence of urinary bladder cancer to the occupation of his patients. They were employed in the dyestuff industry, chronically exposed to large amounts of intermediate arylamines. Laboratory investigations disclosed that rats and mice administered specific azo dyes arylamines or derivatives developed cancer, primarily in the liver. Also, at that time, a possible pesticide, 2-aminofluorene, was tested for chronic toxicity, revealing that it rapidly induced cancers in several organs of rodents. This led to investigations on the mode of action of this class of chemicals, including their metabolic conversion. Biochemical activation to more reactive N-hydroxy compounds was found to occur, mostly in the liver, through what is now known as the cytochrome p450 enzyme systems, and also through prostaglandin synthetases. There were species differences. Guinea pigs were resistant to carcinogenesis because of the low titer of the necessary activating enzymes. In target tissues, a second essential reaction was necessary, namely acylation or sulfate ester formation. The reactive compounds produced display attributes of genotoxicity in appropriate test systems. Interest in this class of compounds increased when of Sugimura and colleagues discovered the formation of mutagens at the surface of cooked meat or fish, that were identified as heterocyclic amines (HCAs). These compounds undergo the same type of activation reactions, as do other arylamines. Epidemiological data suggest that meat eaters may have a higher risk of breast and colon cancer. HCAs induced cancer in rats in these organs and also in the prostate and the pancreas. In addition, there is some evidence that they affect the vascular system. The formation of HCAs during cooking can be decreased by natural and synthetic antioxidants, by tryptophan or proline, or by removing the essential creatine through brief microwave

  10. Naturally occurring diallyl disulfide inhibits the formation of carcinogenic heterocyclic aromatic amines in boiled pork juice.

    PubMed

    Tsai, S J; Jenq, S N; Lee, H

    1996-05-01

    Three heterocyclic aromatic amines, 2-amino-3-methyl-imidazo[4, 5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoxaline and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, have been found in boiled pork juice. We have investigated the effect of naturally occurring organosulfur compounds, which are present in garlic and onion, on mutagen formation in boiled pork juice. Six organosulfur compounds - diallyl disulfide (DAD), dipropyl disulfide (DPD), diallyl sulfide (DAS), allyl methyl sulfide (AMS), allyl mercaptan (AM) and cysteine - were added separately to the pork juice before reflux boiling and then the mutagenicity of each sample was examined with the Salmonella typhimurium strain TA98 in the presence of S9 mix. All six compounds were found to inhibit the mutagenicity of boiled pork juice. The greatest inhibitory effect was observed with DAD and DPD, and this was 111-fold higher than that of the lowest, cysteine. To elucidate the inhibitory effect of DAD on mutagen formation in boiled pork juice, the major mutagenic fractions were monitored after HPLC separation by their mutagenicity with S. typhimurium TA98. By comparing the retention times of authentic IQ compounds from boiled pork juice with those following the addition of DAD, we showed that the mutagenicity of three major fractions was significantly inhibited compared with those same fractions in boiled pork juice alone. In addition, the Maillard reaction products (MRPs) in the boiled pork juice with and without the addition of DAD were quantified and identified by capillary gas chromatography and gas chromatography-mass spectrometry. The results show that the reduction in the total amount of MRPs (pyridines, pyrazines, thiophenes and thiazoles) in boiled pork juice after boiling for 12 h is correlated with their mutagenicity. Among the MRPs, tetrahydrothiophene-3-one exhibited the strongest correlation. These data suggest that the inhibition of IQ mutagen formation by DAD is mediated through the

  11. Heterocyclic aromatic amine content in pre-processed meat cuts produced in Canada.

    PubMed

    Stavric, B; Lau, B P; Matula, T I; Klassen, R; Lewis, D; Downie, R H

    1997-02-01

    In an ongoing survey, the presence of heterocyclic aromatic amines (HAAs) was determined in processed, ready-to-eat meat products sold as 'meat cuts'. HAAs are a group of recently recognized mutagenic/carcinogenic contaminants in foods that are produced during the heat processing of meat. 16 samples of meat cuts (e.g. turkey breast, salami, chicken loaf, cooked ham, all beef meat, pepperoni, etc.), randomly purchased from supermarkets and specialty food stores in the Ottawa area, were analysed for the presence of eight HAAs. The isolation of HAAs was based on sequential liquid-liquid extraction procedures of the samples at both acidic and basic pH values. The mutagenic activity of these samples was determined using the Ames/Salmonella microsome assay with the strain TA98 plus rat liver S-9 metabolic activation. The mutagenicity of these samples ranged from undetectable to slightly active. The highest mutagenic activity, 141 induced revertants/g, was found in a smoked turkey breast sample. 11 samples were not mutagenic, including two that indicated a tendency for inhibition of the spontaneous revertants. The remaining four samples exhibited very low mutagenic activity. For chemical analysis, the extracts were purified with two solid phase extraction cartridges. Quantitative analysis was performed by using liquid chromatography for separation and mass spectrometry for detection. With the exception of trace amounts (0.4 ng/g) of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) in the sample with highest mutagenic activity, the chemical analysis did not detect the presence of any of the eight most frequently found HAAs in fried or broiled meat products. These data suggest that consumption of meat cuts does not present a serious health risk from HAA-type contaminants. PMID:9146732

  12. Activation of aromatic amines to mutagens by bovine bladder and liver cells

    PubMed Central

    Oglesby, Linda; Hix-Baker, Cathy; MacNair, Pat; Sieg, Marianne; Snow, Linda; Langenbach, Robert

    1983-01-01

    A bovine bladder cell-mediated mutagenesis system using Chinese hamster V79 cells and Salmonella typhimurium as target organisms was developed to investigate the capacity of the bladder urothelium to activate chemical carcinogens. Bovine bladder epithelial cells can activate the aromatic amines AF and 4-ABP to intermediates which mutate V79 cells and S. typhimurium TA 98 and TA 100. DMBA was mutagenic to V79 cells but not detectably mutagenic to either Salmonella strain with bladder cell activation. The chemicals tested were not mutagenic to either target organism in the absence of bladder cells. In contrast to the response with DMBA, S. typhimurium was a more sensitive target for the arylamines than V79 cells. These data suggest the value of using multiple end points for assessing metabolic capability. The activation capability of intact bladder cells was compared to disrupted cells, and S-9 prepared from bladder cells used with and without cofactors. When intact cells or S-9 plus cofactors were used as the activation system a dose-dependent increase in revertants was observed for 4-ABP. A bovine liver cell-mediated bacterial mutagenesis system was also developed and the liver and bladder systems compared. For AF, bladder cells appear to be at least ten times more active per viable cell than hepatocytes in producing mutagenic intermediates, while 4-ABP is essentially not mutagenic in the hepatocyte-mediated system. A quantitative comparison of the relative importance of the liver and bladder to activate the chemicals is difficult to make but the data indicate the ability of the bladder epithelium to activate bladder carcinogens. PMID:6339223

  13. Migration kinetics of primary aromatic amines from polyamide kitchenware: Easy and fast screening procedure using fluorescence.

    PubMed

    Sanllorente, S; Sarabia, L A; Ortiz, M C

    2016-11-01

    Primary aromatic amines, PAAs, and their derivatives constitute a health risk and control of their migration from food contact materials is the subject of permanent attention by the authorities. 25.1% of notifications made by Rapid Alert System for Food and Feed in the European Union between 2010 and 2015 concerned PAAs, polyamide cooking utensils being a common source. It is thus useful to have fast and efficient analytical methods for their control. In this work a non-separative, easy, fast and inexpensive spectrofluorimetric method based on the second order calibration of excitation-emission fluorescence matrices (EEMs) was proposed for the determination of aniline (ANL), 2,4-diaminotoluene (2,4-TDA) and 4,4'-methylenedianiline (4,4'-MDA) in polyamide cooking utensils. The procedure made it possible to identify unequivocally each analyte. Trilinearity of the data tensor guarantees the uniqueness of the solution obtained through parallel factor analysis (PARAFAC), so the factors of the decomposition match up with the analytes. The three analytes were unequivocally identified by the correlation between the pure spectra and the PARAFAC excitation and emission spectral loadings. The recovery percentages found were, 82.6%, 112.7% and 84.4% for ANL, 2,4-TDA and 4,4'-MDA respectively. The proposed method was applied to carry out a migration test from polyamide cooking utensils, using a 3% (w/v) acetic acid in aqueous solution as food simulant. Detectable levels of 4,4'-MDA were found in food simulant from some of the investigated cooking utensils. Finally, a kinetic model for the migration of 4,4'-MDA has been fitted to experimental data obtained in the migration test. Thanks to the selectivity of PARAFAC calibration, which greatly simplifies sample treatment avoiding the use of toxic solvents, the developed method follows most green analytical chemistry principles. PMID:27591586

  14. Evaluation of aromatic amines with different purities and different solvent vehicles in the Ames test.

    PubMed

    Harding, Alexander P; Popelier, Paul L A; Harvey, James; Giddings, Amanda; Foster, Graham; Kranz, Michael

    2015-03-01

    Of all the in vitro mutagenicity assays, the Ames test displays the best correlation with rodent carcinogenicity and therefore carries significant weight with the food and drug regulatory bodies. Aromatic amines (AA) are ubiquitous structural groups in food and drug molecules despite the well-documented mutagenic and carcinogenic propensity for many representatives. Furthermore, recent regulatory guidelines (that is ICH M7) requires the hazard assessment of actual and potential impurities by two complementary (Q)SAR prediction methodologies if no carcinogenicity or bacterial mutagenicity data is available. One methodology should be expert-rule-based and the second should be statistics-based. Having encountered numerous reports of contradictory Ames results for members of this chemotype, we undertook systematic Ames tests on a diverse set of 14 AAs of differing purities in different solvents, and as free bases and their salts. The aim of this work was to investigate the reliability of the Ames test for this chemotype leading to the creation of a reference set of AAs for use by medicinal chemists and in silico modelling. Contrary to previous experience, which led to the investigations reported in this publication, the anticipated transformation from an Ames-positive to an Ames-negative after purification only occurred for one compound. Furthermore, this result proved inconclusive after testing as the HCl salt in DMSO and in water. The anticipated change in class from mutagen to non-mutagen, did not occur and this can be read as evidence for the reliability of the Ames test for AAs. PMID:25542092

  15. Differential toxicity of heterocyclic aromatic amines and their mixture in metabolically competent HepaRG cells

    SciTech Connect

    Dumont, Julie; Josse, Rozenn; Lambert, Carine; Antherieu, Sebastien; Le Hegarat, Ludovic; Aninat, Caroline; Robin, Marie-Anne; Guguen-Guillouzo, Christiane

    2010-06-01

    Human exposure to heterocyclic aromatic amines (HAA) usually occurs through mixtures rather than individual compounds. However, the toxic effects and related mechanisms of co-exposure to HAA in humans remain unknown. We compared the effects of two of the most common HAA, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), individually or in combination, in the metabolically competent human hepatoma HepaRG cells. Various endpoints were measured including cytotoxicity, apoptosis, oxidative stress and DNA damage by the comet assay. Moreover, the effects of PhIP and/or MeIQx on mRNA expression and activities of enzymes involved in their activation and detoxification pathways were evaluated. After a 24 h treatment, PhIP and MeIQx, individually and in combination, exerted differential effects on apoptosis, oxidative stress, DNA damage and cytochrome P450 (CYP) activities. Only PhIP induced DNA damage. It was also a stronger inducer of CYP1A1 and CYP1B1 expression and activity than MeIQx. In contrast, only MeIQx exposure resulted in a significant induction of CYP1A2 activity. The combination of PhIP with MeIQx induced an oxidative stress and showed synergistic effects on apoptosis. However, PhIP-induced genotoxicity was abolished by a co-exposure with MeIQx. Such an inhibitory effect could be explained by a significant decrease in CYP1A2 activity which is responsible for PhIP genotoxicity. Our findings highlight the need to investigate interactions between HAA when assessing risks for human health and provide new insights in the mechanisms of interaction between PhIP and MeIQx.

  16. N-acetyltransferase 2, exposure to aromatic and heterocyclic amines, and receptor-defined breast cancer.

    PubMed

    Rabstein, Sylvia; Brüning, Thomas; Harth, Volker; Fischer, Hans-Peter; Haas, Susanne; Weiss, Tobias; Spickenheuer, Anne; Pierl, Christiane; Justenhoven, Christina; Illig, Thomas; Vollmert, Caren; Baisch, Christian; Ko, Yon-Dschun; Hamann, Ute; Brauch, Hiltrud; Pesch, Beate

    2010-03-01

    The role of N-acetyltransferase 2 (NAT2) polymorphism in breast cancer is still unclear. We explored the associations between potential sources of exposure to aromatic and heterocyclic amines (AHA), acetylation status and receptor-defined breast cancer in 1020 incident cases and 1047 population controls of the German GENICA study. Acetylation status was assessed as slow or fast. Therefore, NAT2 haplotypes were estimated using genotype information from six NAT2 polymorphisms. Most probable haplotypes served as alleles for the deduction of NAT2 acetylation status. The risks of developing estrogen receptor alpha (ER) and progesterone receptor (PR)-positive or negative tumors were estimated for tobacco smoking, consumption of red meat, grilled food, coffee, and tea, as well as expert-rated occupational exposure to AHA with logistic regression conditional on age and adjusted for potential confounders. Joint effects of these factors and NAT2 acetylation status were investigated. Frequent consumption of grilled food and coffee showed higher risks in slow acetylators for receptor-negative tumors [grilled food: ER-: odds ratio (OR) 2.57, 95% confidence interval (CI) 1.07-6.14 for regular vs. rare; coffee: ER-: OR 2.55, 95% CI 1.22-5.33 for >or=4 vs. 0 cups/day]. We observed slightly higher risks for never smokers that are fast acetylators for receptor-positive tumors compared with slow acetylators (ER-: OR 1.32, 95% CI 1.00-1.73). Our results support differing risk patterns for receptor-defined breast cancer. However, the modifying role of NAT2 for receptor-defined breast cancer is difficult to interpret in the light of complex mixtures of exposure to AHA. PMID:19996973

  17. An in silico method for predicting Ames activities of primary aromatic amines by calculating the stabilities of nitrenium ions.

    PubMed

    Bentzien, Jörg; Hickey, Eugene R; Kemper, Raymond A; Brewer, Mark L; Dyekjaer, Jane D; East, Stephen P; Whittaker, Mark

    2010-02-22

    In this paper, we describe an in silico first principal approach to predict the mutagenic potential of primary aromatic amines. This approach is based on the so-called "nitrenium hypothesis", which was developed by Ford et al. in the early 1990s. This hypothesis asserts that the mutagenic effect for this class of molecules is mediated through the transient formation of a nitrenium ion and that the stability of this cation is correlated with the mutagenic potential. Here we use quantum mechanical calculations at different levels of theory (semiempirical AM1, ab initio HF/3-21G, HF/6-311G(d,p), and DFT/B3LYP/6-311G(d,p)) to compute the stability of nitrenium ions. When applied to a test set of 257 primary aromatic amines, we show that this method can correctly differentiate between Ames active and inactive compounds, and furthermore that it is able to rationalize and predict SAR trends within structurally related chemical series. For this test set, the AM1 nitrenium stability calculations are found to provide a good balance between speed and accuracy, resulting in an overall accuracy of 85%, and sensitivity and specificity of 91% and 72%, respectively. The nitrenium-based predictions are also compared to the commercial software packages DEREK, MULTICASE, and the MOE-Toxicophore descriptor. One advantage of the approach presented here is that the calculation of relative stabilities results in a continuous spectrum of activities and not a simple yes/no answer. This allows us to observe and rationalize subtle trends due to the different electrostatic properties of the organic molecules. Our results strongly indicate that nitrenium ion stability calculations should be used as a complementary approach to assist the medicinal chemist in prioritizing and selecting nonmutagenic primary aromatic amines during preclinical drug discovery programs. PMID:20078034

  18. Determination of aromatic amines in hair dye and henna samples by ion-pair extraction and gas chromatography-mass spectrometry.

    PubMed

    Akyüz, Mehmet; Ata, Sevket

    2008-05-12

    A gas chromatography-mass spectrometry (GC-MS) method has been proposed for the determination of carcinogenic and toxic aromatic amines in hair dye, henna and dyed hair samples. The method includes ion-pair extraction of aromatic amines from aqueous samples with bis-2-ethylhexylphosphate (BEHPA) released after solving the samples in acidic solution followed by sonication, derivatisation of compounds with isobutyl chloroformate (IBCF) and their GC-MS analysis in both electron impact (EI) and positive and negative ion chemical ionisation (PNICI) mode as their isobutyloxycarbonyl (isoBOC) derivatives. The obtained recoveries of aromatic amines ranged from 92.2 to 98.4% and the precision of this method, as indicated by the relative standard deviations (RSDs) was within the range of 0.7-4.2%. The detection limits obtained from calculations by using GC-MS results based on signal-to-noise ratio (S/N)=3 were within the range from 0.02 to 0.20 ng/g. In the present study, the commercially available 54 permanent hair dye, 35 modified or natural henna and 15 dyed hair samples were analysed for the aromatic amines by the proposed method and the method was shown to be suitable to determine the aromatic amine ingredients and metabolites of these commercial products. PMID:18280687

  19. Plasma proteins as early biomarkers of exposure to carcinogenic aromatic amines.

    PubMed

    Miller, M J; Parmelee, D C; Benjamin, T; Sechi, S; Dooley, K L; Kadlubar, F F

    1994-12-01

    Two-dimensional gel electrophoresis (2DG) has been used to study the changes induced in dog plasma polypeptides by the known urinary bladder carcinogens, 4-aminobiphenyl (4-ABP) and 2-naphthylamine (2-NA). Treatment with 3-aminobiphenyl (3-ABP) and 1-naphthylamine (1-NA), both considered to be non-carcinogenic, were used as controls. The purpose of this study was: (1) to determine whether or not changes that occurred in the plasma protein patterns were specific to 4-ABP and/or other related carcinogenic arylamines; (2) to measure the time course in the changes of the major polypeptides during dosing and their resynthesis during a recovery period; and (3) to determine, by microsequencing, the biochemical identity of the affected proteins. The results indicate that only the most potent carcinogen, 4-ABP, had the effect of suppressing the expression of some proteins, while the other aromatic amines caused no discernible change in the 2DG patterns during a 12-week dosing period. The 4-ABP caused dramatic suppression of two sets of proteins. One set of three spots had an apparent molecular weight of 32.5 kDa, and a pI of 5.8-6.0. The major component in this group was identified as the beta-chain of haptoglobin. Expression of this protein decreased markedly during the first 2 weeks of treatment and recovered slowly after dosing stopped. Since haptoglobin functions to bind with free hemoglobin and facilitates its elimination from the blood stream, these results can be rationalized as a consequence of 4-ABP binding to hemoglobin in the erythrocyte, resulting in cell death and hemolysis. The 4-ABP modified hemoglobin then binds to haptoglobin and this tertiary complex is purged from the blood stream, resulting in the disappearance of free haptoglobin. A second set of spots (mol. wt., 65 kDa; pI, 6.5-6.6) disappeared much faster than the haptoglobin, and recovered more quickly. The major protein is about one-fifth the intensity of haptoglobin and appeared to be N

  20. Heterocyclic Aromatic Amines in Domestically Prepared Chicken and Fish from Singapore Chinese Households

    SciTech Connect

    Salmon, C P; Knize, M G; Felton, J S; Zhao, B; Seow, A

    2005-05-16

    Chicken and fish samples prepared by 42 Singapore Chinese in their homes were obtained. Researchers were present to collect data on raw meat weight, cooking time, maximum cooking surface temperature, and cooked meat weight. Each participant prepared one pan-fried fish sample and two pan-fried chicken samples, one marinated, one not marinated. The cooked samples were analyzed for five heterocyclic aromatic amine (HAA) mutagens, including MeIQx (2-amino 3,8-dimethylimidazo[4,5-f]quinoxaline); 4,8-DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline); 7,8-DiMeIQx (2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline); PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), and IFP (2-amino-(1,6-dimethylfuro[3,2-e]imidazo [4,5-b])pyridine). A paired Student's t-test showed that marinated chicken had lower concentrations of PhIP (p<0.05), but higher concentrations of MeIQx (p<0.05) and 4,8-DiMeIQx (p<0.001) than non-marinated chicken, and also that weight loss due to cooking was less in marinated chicken than in non-marinated chicken (p<0.001). Interestingly, the maximum cooking surface temperature was higher for fish than for either marinated or non-marinated chicken (P<0.001), yet fish was lower in 4,8-DiMeIQx per gram than marinated or non-marinated chicken (p<0.001), lower in PhIP than non-marinated chicken (P<0.05), and lost less weight due to cooking than either marinated or non-marinated chicken (P<0.001). Fish was also lower in MeIQx and 7,8-DiMeIQx than marinated chicken (P<0.05). This study provides new information on HAA content in the Singapore Chinese diet.

  1. Suitability of the in vitro Caco-2 assay to predict the oral absorption of aromatic amine hair dyes.

    PubMed

    Obringer, Cindy; Manwaring, John; Goebel, Carsten; Hewitt, Nicola J; Rothe, Helga

    2016-04-01

    Oral absorption is a key element for safety assessments of cosmetic ingredients, including hair dye molecules. Reliable in vitro methods are needed since the European Union has banned the use of animals for the testing of cosmetic ingredients. Caco-2 cells were used to measure the intestinal permeability characteristics (Papp) of 14 aromatic amine hair dye molecules with varying chemical structures, and the data were compared with historical in vivo oral absorption rat data. The majority of the hair dyes exhibited Papp values that indicated good in vivo absorption. The moderate to high oral absorption findings, i.e. ≥60%, were confirmed in in vivo rat studies. Moreover, the compound with a very low Papp value (APB: 3-((9,10-dihydro-9,10-dioxo-4-(methylamino)-1-anthracenyl)amino)-N,N-dimethyl-N-propyl-1-propanaminium) was poorly absorbed in vivo as well (5% of the dose). This data set suggests that the Caco-2 cell model is a reliable in vitro tool for the determination of the intestinal absorption of aromatic amines with diverse chemical structures. When used in combination with other in vitro assays for metabolism and skin penetration, the Caco-2 model can contribute to the prediction and mechanistic interpretation of the absorption, metabolism and elimination properties of cosmetic ingredients without the use of animals. PMID:26578466

  2. Visual Recognition of Aliphatic and Aromatic Amines Using a Fluorescent Gel: Application of a Sonication-Triggered Organogel.

    PubMed

    Pang, Xuelei; Yu, Xudong; Lan, Haichuang; Ge, Xiaoting; Li, Yajuan; Zhen, Xiaoli; Yi, Tao

    2015-06-24

    A naphthalimide-based fluorescent gelator (N1) containing an alkenyl group has been designed and characterized. This material is able to gelate alcohols via a precipitate-to-gel transformation when triggered with ultrasound for less than 2 min (S-gel). The gelation process in n-propanol was studied by means of absorption, fluorescence, and IR spectra, scanning electron microscopy (SEM) images, and X-ray diffraction patterns. The fluorescence intensity of N1 decreased during the gelation process in a linear relationship with the sonication time. The S-gel of N1 could be used to sense aliphatic and aromatic amines by measuring the change in the signal output. For example, the addition of propylamine to the S-gel of N1 resulted in a dramatic enhancement of the fluorescence intensity, accompanied by a gel-to-sol transition. On the contrary, when the S-gel of N1 was treated with aromatic amines such as aniline, fluorescence was quenched and there was no gel collapse. The sensing mechanisms were studied by (1)H NMR, small-angle X-ray scattering, SEM and spectroscopic experiments. It is proposed that isomerization of the alkenyl group of N1 from the trans to cis form occurs when the S-gel is treated with propylamine, resulting in a gel-sol transition. However, the aromatic aniline molecules prefer to insert into the gel networks of N1 via hydrogen-bonding and charge-transfer interactions, maintaining the gel state. As potential applications, testing strips of N1 were prepared to detect aniline. PMID:26040296

  3. Carbon, hydrogen, and nitrogen isotope fractionation associated with oxidative transformation of substituted aromatic N-alkyl amines.

    PubMed

    Skarpeli-Liati, Marita; Pati, Sarah G; Bolotin, Jakov; Eustis, Soren N; Hofstetter, Thomas B

    2012-07-01

    We investigated the mechanisms and isotope effects associated with the N-dealkylation and N-atom oxidation of substituted N-methyl- and N,N-dimethylanilines to identify isotope fractionation trends for the assessment of oxidations of aromatic N-alkyl moieties by compound-specific isotope analysis (CSIA). In laboratory batch model systems, we determined the C, H, and N isotope enrichment factors for the oxidation by MnO(2) and horseradish peroxidase (HRP), derived apparent (13)C-, (2)H-, and (15)N-kinetic isotope effects (AKIEs), and characterized reaction products. The N-atom oxidation pathway leading to radical coupling products typically exhibited inverse (15)N-AKIEs (up to 0.991) and only minor (13)C- and (2)H-AKIEs. Oxidative N-dealkylation, in contrast, was subject to large normal (13)C- and (2)H-AKIEs (up to 1.019 and 3.1, respectively) and small (15)N-AKIEs. Subtle changes of the compound's electronic properties due to different types of aromatic and/or N-alkyl substituents resulted in changes of reaction mechanisms, rate-limiting step(s), and thus isotope fractionation trends. The complex sequence of electron and proton transfers during the oxidative transformation of substituted aromatic N-alkyl amines suggests highly compound- and mechanism-dependent isotope effects precluding extrapolations to other organic micropollutants reacting along the same degradation pathways. PMID:22681573

  4. Photocatalytic organic transformation by layered double hydroxides: highly efficient and selective oxidation of primary aromatic amines to their imines under ambient aerobic conditions.

    PubMed

    Yang, Xiu-Jie; Chen, Bin; Li, Xu-Bing; Zheng, Li-Qiang; Wu, Li-Zhu; Tung, Chen-Ho

    2014-06-25

    We report the first application of layered double hydroxide as a photocatalyst in the transformation of primary aromatic amines to their corresponding imines with high efficiency and selectivity by using oxygen in an air atmosphere as a terminal oxidant under light irradiation. PMID:24827163

  5. Effects of smoking, aromatic amines, and chromates on CD4{sup +} and CD8{sup +} T lymphocytes in male workers

    SciTech Connect

    Tanigawa, Takeshi; Araki, Shunichi; Sata, Fumihiro; Nakata, Akinori; Araki, Takaharu

    1998-07-01

    To investigate effects of smoking, aromatic amines (AAs), and chromates (CRs) on Tlymphocyte subpopulations, the authors measured CD3{sup +}, CD4{sup +}, and CD8{sup +} T lymphocytes in the peripheral blood of 33 nonexposed workers, 25 AA-use workers, 27 AA-production workers, and 19 CR workers (all subjects were males). The number of CD4{sup +} T lymphocytes in smokers of nonexposed workers was significantly larger than that of the nonsmokers; also, the numbers of CD4{sup +} and CD3{sup +} T lymphocytes in smokers of each group of AA-production and AA-use workers were significantly larger than those in nonsmokers. Numbers of CD4{sup +} and CD3{sup +} T lymphocytes in nonsmokers of AA-production and CR workers were significantly smaller than those in nonsmokers of nonexposed workers; the number of CD8{sup +} T lymphocytes in nonsmokers of CR workers was significantly smaller than that in nonsmokers of nonexposed workers.

  6. The effect of aromatic amines and phenols in the thiyl-induced reactions of polyunsaturated fatty acids

    NASA Astrophysics Data System (ADS)

    Tartaro Bujak, Ivana; Chatgilialoglu, Chryssostomos; Ferreri, Carla; Valgimigli, Luca; Amorati, Riccardo; Mihaljević, Branka

    2016-07-01

    Thiols are well known for their role in cellular redox homeostasis, while aromatic amines and phenols are the best known classes of chain-breaking antioxidants. On the other hand, thiyl radicals are known to catalyse the double bond isomerization in PUFA. We investigated the role and interplay of 2-mercaptoethanol and diphenylamine in the parallel processes of peroxidation and cis-trans isomerization of linoleic acid (LA) during gamma radiolysis, both in solution and micelles. Both compounds, used alone were able to protect LA from oxidation; however pro-oxidant activity and enhanced isomerization was observed when they were used together, depending on the experimental settings. Instead, α-tocopherol protected LA from both oxidation and isomerization in the presence of thiols under any tested settings. The mechanistic scenario is discussed highlighting the role of diphenylaminyl radicals in promoting thiyl-radical-induced cis-trans isomerization in the presence of oxygen.

  7. Extrapolation of systemic bioavailability assessing skin absorption and epidermal and hepatic metabolism of aromatic amine hair dyes in vitro.

    PubMed

    Manwaring, John; Rothe, Helga; Obringer, Cindy; Foltz, David J; Baker, Timothy R; Troutman, John A; Hewitt, Nicola J; Goebel, Carsten

    2015-09-01

    Approaches to assess the role of absorption, metabolism and excretion of cosmetic ingredients that are based on the integration of different in vitro data are important for their safety assessment, specifically as it offers an opportunity to refine that safety assessment. In order to estimate systemic exposure (AUC) to aromatic amine hair dyes following typical product application conditions, skin penetration and epidermal and systemic metabolic conversion of the parent compound was assessed in human skin explants and human keratinocyte (HaCaT) and hepatocyte cultures. To estimate the amount of the aromatic amine that can reach the general circulation unchanged after passage through the skin the following toxicokinetically relevant parameters were applied: a) Michaelis-Menten kinetics to quantify the epidermal metabolism; b) the estimated keratinocyte cell abundance in the viable epidermis; c) the skin penetration rate; d) the calculated Mean Residence Time in the viable epidermis; e) the viable epidermis thickness and f) the skin permeability coefficient. In a next step, in vitro hepatocyte Km and Vmax values and whole liver mass and cell abundance were used to calculate the scaled intrinsic clearance, which was combined with liver blood flow and fraction of compound unbound in the blood to give hepatic clearance. The systemic exposure in the general circulation (AUC) was extrapolated using internal dose and hepatic clearance, and Cmax was extrapolated (conservative overestimation) using internal dose and volume of distribution, indicating that appropriate toxicokinetic information can be generated based solely on in vitro data. For the hair dye, p-phenylenediamine, these data were found to be in the same order of magnitude as those published for human volunteers. PMID:26028483

  8. The effects of cooking on wire and stone barbecue at different cooking levels on the formation of heterocyclic aromatic amines and polycyclic aromatic hydrocarbons in beef steak.

    PubMed

    Oz, Fatih; Yuzer, M Onur

    2016-07-15

    The effects of type of barbecue (wire and stone) and cooking levels (rare, medium, well-done and very well-done) on the formation of heterocyclic aromatic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) in beef steak were investigated. Varying levels of IQx (up to 0.29 ng/g), IQ (up to 0.93 ng/g), MeIQx (up to 0.08 ng/g), MeIQ (up to 0.75 ng/g), 7,8-DiMeIQx (up to 0.08 ng/g), 4,8-DiMeIQx (up to 4.95 ng/g), PhIP (up to 6.24 ng/g) and AαC (up to 0.20 ng/g) were determined, while MeAαC was not detected. The total HCA amounts in wire barbecued samples were higher than stone barbecued samples. Total HCA contents of the samples ranged between nd and 13.52 ng/g. In terms of PAHs, varying levels of BaA (up to 0.34 ng/g), Chry (up to 0.28 ng/g), BbF (up to 0.39 ng/g), BkF (up to 0.90 ng/g), BaP (up to 0.29 ng/g) and Bghip (up to 0.43 ng/g) were determined, while DahA and IncdP were not detected. The total PAH amounts in stone barbecued samples were higher than those of wire barbecued samples. Total PAH amounts of the samples ranged between nd and 2.63 ng/g. PMID:26948589

  9. Effect of ionic liquid on the determination of aromatic amines as contaminants in hair dyes by liquid chromatography coupled to electrochemical detection.

    PubMed

    Lizier, Thiago Mescoloto; Boldrin Zanoni, Maria Valnice

    2012-01-01

    The room temperature ionic liquid (IL) 1-butyl-3-methylimidazolium bis-(trifluorometanesulfonyl)imide BMIm[NTf₂] was used as a novel medium for improvement of separation and quantization of 16 aromatic amines typically present as contaminants in consumer products and detected by HPLC coupled to an electrochemical detector. The aromatic amines, namely 4,4'-diaminodiphenylmethane, 4-chloroaniline, 2-methoxy-5-methyl-aniline, 3,3'-dimethylbenzidine, 2,4-diaminotoluidine, 2-chloro-4-nitroaniline, 4,4'-oxydianiline, aniline, 3,3'-ichlorobenzidine, benzidine, 4-aminobiphenyl, o-dianisidine, o-anisidine, o-toluidine, 4,4'-methylene-bis-2-chloroaniline and 2-naphthylamine are oxidized in methanol/BMIm[NTf₂] at a potential around +0.68V to +0.93V vs. Ag/AgCl at a glassy carbon electrode, which is the base for their determination by HPLC/ED. Using the optimized conditions of methanol/BMIm[NTf₂] 70:30 (v/v) as mobile phase, flow-rate of 0.8 mL·min⁻¹, column CLC-ODS, Eap = +1.0 V and T = 40 °C analytical curves were constructed for each of the tested amines. Good linearity was obtained in the concentration range of 1.09 mg·L⁻¹ to 217 mg·L⁻¹, with excellent correlation coefficients. The limits of detection reached 0.021 mg·L⁻¹ to 0.246 mg·L⁻¹ and good relative standard deviations (RSD, n = 3) were obtained from the measurements. Satisfactory recovery for each aromatic amine was achieved, ranging from 95 to 103%. The developed method was successfully applied to determine six aromatic amines present as contaminants in commercial hair dye samples. PMID:22751261

  10. Quantitative determination of 22 primary aromatic amines by cation-exchange solid-phase extraction and liquid chromatography-mass spectrometry.

    PubMed

    Aznar, Margarita; Canellas, Elena; Nerín, Cristina

    2009-07-01

    Primary aromatic amines (PAAs) have been broadly studied due to their high toxicity. In this work a method for the analysis of 22 PAAs in aqueous simulants has been developed. The method is based on a solid-phase extraction step using cation-exchange cartridges and the subsequent analysis of the extracts by ultra-high-performance liquid chromatography with mass spectrometric detection. The recoveries obtained for all the amines analyzed ranged between 81 and 109%, linear range was between 0.03 and 75 microg L(-1), with the RSD values between 4.5 and 13.4% and an average value of 7.5% and limits of detection at microg L(-1) level. The method has been applied to two real samples obtained from migration experiments of polyurethane based laminates to simulant B (water with 3% (w/v) acetic acid) which represents the worst case for the migration of aromatic amines. The main amines found in both samples were methylenedianiline isomers, obtained from the corresponding residual diisocyanates used during polyurethane adhesive polymerization. The total amine concentration found was 26 and 6.3 microg of aniline equivalents per kg of food simulant. PMID:19464690

  11. In vitro binding of mutagenic heterocyclic aromatic amines by Bifidobacterium pseudocatenulatum G4.

    PubMed

    Faridnia, F; Hussin, A S M; Saari, N; Mustafa, S; Yee, L Y; Manap, M Y A

    2010-06-01

    Consumption of probiotics has been associated with decreased risk of colon cancer and reported to have antimutagenic/ anti-carcinogenic properties. One possible mechanism for this effect involves physical binding of the mutagenic compounds, such as heterocyclic amines (HCAs), to the bacteria. Therefore, the objective of this study was to examine the binding capacity of bifidobacterial strains of human origin on mutagenic heterocyclic amines which are suspected to play a role in human cancers. In vitro binding of the mutagens Trp-p-2, IQ, MeIQx, 7,8DiMeIQx and PhIP by three bacterial strains in two media of different pH was analysed using high performance liquid chromatography. Bifidobacterium pseudocatenulatum G4 showed the highest decrease in the total HCAs content, followed by Bifidobacterium longum, and Escherichia coli. pH affects binding capacity; the highest binding was obtained at pH 6.8. Gram-positive tested strains were found to be consistently more effective than the gram-negative strain. There were significant decreases in the amount of HCAs in the presence of different cell concentrations of B. pseudocatenulatum G4; the highest decrease was detected at the concentration of 10(10) cfu/ml. The results showed that HCAs were able to bind with all bacterial strains tested in vitro, thus it may be possible to decrease their absorption by human intestine and increase their elimination via faeces. PMID:21831754

  12. Extrapolation of systemic bioavailability assessing skin absorption and epidermal and hepatic metabolism of aromatic amine hair dyes in vitro

    SciTech Connect

    Manwaring, John; Rothe, Helga; Obringer, Cindy; Foltz, David J.; Baker, Timothy R.; Troutman, John A.; Hewitt, Nicola J.; Goebel, Carsten

    2015-09-01

    Approaches to assess the role of absorption, metabolism and excretion of cosmetic ingredients that are based on the integration of different in vitro data are important for their safety assessment, specifically as it offers an opportunity to refine that safety assessment. In order to estimate systemic exposure (AUC) to aromatic amine hair dyes following typical product application conditions, skin penetration and epidermal and systemic metabolic conversion of the parent compound was assessed in human skin explants and human keratinocyte (HaCaT) and hepatocyte cultures. To estimate the amount of the aromatic amine that can reach the general circulation unchanged after passage through the skin the following toxicokinetically relevant parameters were applied: a) Michaelis–Menten kinetics to quantify the epidermal metabolism; b) the estimated keratinocyte cell abundance in the viable epidermis; c) the skin penetration rate; d) the calculated Mean Residence Time in the viable epidermis; e) the viable epidermis thickness and f) the skin permeability coefficient. In a next step, in vitro hepatocyte K{sub m} and V{sub max} values and whole liver mass and cell abundance were used to calculate the scaled intrinsic clearance, which was combined with liver blood flow and fraction of compound unbound in the blood to give hepatic clearance. The systemic exposure in the general circulation (AUC) was extrapolated using internal dose and hepatic clearance, and C{sub max} was extrapolated (conservative overestimation) using internal dose and volume of distribution, indicating that appropriate toxicokinetic information can be generated based solely on in vitro data. For the hair dye, p-phenylenediamine, these data were found to be in the same order of magnitude as those published for human volunteers. - Highlights: • An entirely in silico/in vitro approach to predict in vivo exposure to dermally applied hair dyes • Skin penetration and epidermal conversion assessed in human

  13. [Identification of banned aromatic amines and their isomers in textiles by ultra-performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry].

    PubMed

    Ye, Xiwen; Peng, Yan; Niu, Zengyuan; Gao, Yonggang; Luo, Xin; Zou, Li; Zhou, Minghui

    2014-09-01

    A method of ultra-performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry (UPLC-LTQ/Orbitrap MS) was used to screen and confirm 24 banned aromatic amines and their 14 isomers at the same time. The main factors influencing the separation including the column, and the nature of make-up solvent were optimized. Under the optimized experimental conditions, the analytes were reduced to banned aromatic amine with sodium dithionite, extracted by methyl tert-butyl ether and loaded onto a ZORBAX SB-C18 column (150 mm x 2.1 mm, 5 μm) with a gradient elution of methanol and 0.1% formic acid aqueous solution, and finally detected by LTQ/Orbitrap MS. The screening and quantitative analysis were carried out by the accurate mass of quasi-molecular ion and the peak in extracted chromatogram with accurate mass. The correlation coefficients were higher than 0.99 and the limits of detection were in the range of 0.5-5 μg/kg. The method could screen and confirm the 24 banned aromatic amines and their 14 isomers at the same time. The results were 1.56 mg/kg of 4-chloroaniline, 0.34 mg/kg of o-toluidine, and 0.81 mg/kg of 2,6-toluylenediamine with the relative standard deviations ranging from 0.27% to 1.32% in actual samples. The results indicate that the developed method is simple, efficient and precise, and can be a reliable technique for the separation of the 24 banned aromatic amines and their 14 isomers in textile samples. PMID:25752096

  14. The interaction of diamines and polyamines with the peroxidase-catalyzed metabolism of aromatic amines: a potential mechanism for the modulation of aniline toxicity.

    PubMed

    Michail, Karim; Aljuhani, Naif; Siraki, Arno G

    2013-03-01

    Synthetic and biological amines such as ethylenediamine (EDA), spermine, and spermidine have not been previously investigated in free-radical biochemical systems involving aniline-based drugs or xenobiotics. We aimed to study the influence of polyamines in the modulation of aromatic amine radical metabolites in peroxidase-mediated free radical reactions. The aniline compounds tested caused a relatively low oxidation rate of glutathione in the presence of horseradish peroxidase (HRP), and H2O2; however, they demonstrated marked oxygen consumption when a polyamine molecule was present. Next, we characterized the free-radical products generated by these reactions using spin-trapping and electron paramagnetic resonance (EPR) spectrometry. Primary and secondary but not tertiary polyamines dose-dependently enhanced the N-centered radicals of different aniline compounds catalyzed by either HRP or myeloperoxidase, which we believe occurred via charge transfer intermediates and subsequent stabilization of aniline-derived radical species as suggested by isotopically labeled aniline. Aniline/peroxidase reaction product(s) were monitored at 435 nm by kinetic spectrophotometry in the presence and absence of a polyamine additive. Using gas chromatography-mass spectrometry, the dimerziation product of aniline, azobenzene, was significantly amplified when EDA was present. In conclusion, di- and poly-amines are capable of enhancing the formation of aromatic-amine-derived free radicals, a fact that is expected to have toxicological consequences. PMID:23537436

  15. Aliphatic and aromatic amines in atmospheric aerosol particles: comparison of three ionization techniques in liquid chromatography-mass spectrometry and method development.

    PubMed

    Ruiz-Jiménez, José; Hautala, Sanna; Parshintsev, Jevgeni; Laitinen, Totti; Hartonen, Kari; Petäjä, Tuukka; Kulmala, Markku; Riekkola, Marja-Liisa

    2012-08-15

    A complete methodology was developed for the determination of ten aliphatic and nine aromatic amines in atmospheric aerosol particles. Before the liquid chromatography - tandem mass spectrometric separation and determination, the derivatization reaction of the analytes using dansyl chloride was accelerated by ultrasounds. From three different ionization techniques studied electrospray ionization was superior in terms of sensitivity, linearity, repeatability and reproducibility over atmospheric pressure chemical ionization and photoionization for the target analytes. The method developed was validated for the gas phase, 30 nm and total suspended atmospheric aerosol particles. The method quantification limits ranged between 1.8 and 71.7 pg. The accuracy and the potential matrix effects were evaluated using a standard addition methodology. Recoveries from 92.1% to 109.1%, the repeatability from 0.6% to 8.4% and the reproducibility from 2.3% to 9.8% were obtained. The reliability of the methodology was proved by the statistical evaluation. Finally, the developed methodology was applied to the determination of the target analytes in eight size separated ultrafine particulate (Dp=30±4 nm) samples and in eight total suspended particulate samples collected at the SMEAR II station. The mean concentrations for aliphatic amines were between 0.01 and 42.67 ng m(-3) and for aromatic amines between 0.02 and 1.70 ng m(-3). Thirteen amines were quantified for the first time in 30 nm aerosol particles. PMID:22841047

  16. Microextraction by packed sorbent and salting-out-assisted liquid-liquid extraction for the determination of aromatic amines formed from azo dyes in textiles.

    PubMed

    Sánchez, Miguel del Nogal; Santos, Patricia Martín; Sappó, Cristina Pérez; Pavón, José Luis Pérez; Cordero, Bernardo Moreno

    2014-02-01

    EU legislation prohibits the use of certain azo dyes which, on reduction, form any of 22 aromatic amines listed in Regulation (EC) 1907/2006 at concentrations above the threshold limit of 30 mg Kg(-1). Two different extraction techniques for the determination of aromatic amines formed from azo dyes in textiles in combination with gas chromatography-mass spectrometry (GC-MS) are described. The first one is based on microextraction by packed sorbent (MEPS) and the other approach involves salting-out-assisted liquid-liquid extraction (SALLE). The influence of several parameters on the efficiency of the extraction using MEPS (sorbent material, sample volume, elution solvent, elution volume and washing steps, among others) and SALLE (extraction volume and amount of salt) were investigated. In addition, chromatographic separation was optimized and quadrupole mass spectrometry was evaluated using the synchronous SIM/scan data acquisition mode. The repeatability (n=8, S/N=3) of the methods, calculated as the relative standard deviation (RSD) was below 15 and 11% for all compounds when MEPS and SALLE were used, respectively. Standard additions procedure was used to quantify the aromatic amines in the textil samples. The detection limits in the samples for both methods were lower than the maximum value allowed by legislation. The results obtained in the analysis of textiles revealed the presence of o-anisidine, p-chloroaniline, 4-chloro-o-toluidine, 2-naphthylamine and 3,3'-dimethoxybenzidine in some of them. PMID:24401428

  17. Influence of beer marinades on the reduction of carcinogenic heterocyclic aromatic amines in charcoal-grilled pork meat.

    PubMed

    Viegas, Olga; Moreira, Patrícia S; Ferreira, Isabel M P L V O

    2015-01-01

    The effect of beer marinades on the formation of heterocyclic aromatic amines (HAs) was examined in charcoal-grilled pork. Pilsner, non-alcoholic pilsner and black beers (coded respectively as PB, P0B and BB) were assayed and unmarinated samples cooked under similar conditions provided reference HAs levels. Two thermic (PhIP and 4,8-DiMeIQx) and three pyrolytic HAs (Trp-P-1, AαC, MeAαC) were quantified in unmarinated meat samples. Marinating meat in beer resulted in a significant decrease of PhIP, Trp-P-1 and AαC (p < 0.05). 4,8-DiMeIQx formation was inhibited only by BB marinade. No significant effect was observed on MeAαC formation. All beers reduced total HA formation in charcoal-grilled pork, black beer being the most efficient with a level of 90% inhibition. A strong positive correlation was observed between the inhibitory effect of beer on total HA formation and their antioxidant activity. Beer marinades mitigate the impact of consumption of well-done grilled pork meat reducing the formation of cooking carcinogens. PMID:25604939

  18. Inhibitory effect of antioxidant-rich marinades on the formation of heterocyclic aromatic amines in pan-fried beef.

    PubMed

    Viegas, Olga; Amaro, L Filipe; Ferreira, Isabel M P L V O; Pinho, Olívia

    2012-06-20

    The inhibitory effect of antioxidant-rich marinades containing beer and white wine (with/without alcohol) alone or mixed with herbs commonly used as meat flavoring (garlic, ginger, thyme, rosemary, and red chili pepper) on the formation of heterocyclic aromatic amines (HAs) in pan-fried beef was studied. Radical-scavenging activity was evaluated by DPPH assay, before the addition of meat to the marinade (T0) and after 4 h of meat marinating (T4). At T0, wine with herbs possessed the highest scavenging activity (73.5%), followed by wine (72.5%), dealcoholized wine with herbs (53.4%), beer and herbs (41.7%), dealcoholized wine (39.6%), and beer (25.9%). At T4, a decrease in the radical-scavenging activity of all marinades was observed, although with a similar radical-scavenging profile. All of the six marinades under the study reduced the total amount of HAs, keeping meat with good overall sensory quality. Beer marinades were more efficient than white wine marinades, and the addition of herbs provided a superior inhibitory effect, reducing around 90% of HAs. No correlation was observed between radical-scavenging activity of marinades and total or individual HAs formation. Herbs explained around 30% of inhibition of PhIP formation, whereas alcohol increased PhIP formation. PMID:22642699

  19. Heterocyclic aromatic amines and their contribution to the bacterial mutagenicity of the particulate phase of cigarette smoke.

    PubMed

    Roemer, Ewald; Meisgen, Thomas; Diekmann, Joerg; Conroy, Lynda; Stabbert, Regina

    2016-01-22

    Heterocyclic aromatic amines (HAAs) rank among the strongest known mutagens. Approximately 30 HAAs have been found in cooked foods (broiled, fried, and grilled) and several HAAs have been characterized as animal carcinogens. Nine HAAs have also been reported to be constituents of cigarette smoke (CS) raising concerns that HAAs might contribute significantly to the known carcinogenicity of CS. As HAAs are found predominantly in the total particulate matter (TPM) of CS, an improved method for the quantification of HAAs in TPM is reported allowing detection and quantification of 8 HAAs in a single run. The mutagenic potency of these HAAs and that of TPM from the reference cigarette 2R4F was determined in the Salmonella Reverse Mutation Assay (Ames assay) with tester strain TA98 and a metabolic activation system. The 8 HAAs, when applied together in the Ames assay, showed a clear sub-additive response. Likewise, the combination of HAAs and TPM, if at all, gave rise to a slight sub-additive response. In both cases, however, the sub-additive response in the Ames assay was observed at HAA doses that are far above the amounts found in CS. The contribution of the individual HAAs to the total mutagenic activity of TPM was calculated and experimentally confirmed to be approximately 1% of the total mutagenic activity. Thus, HAAs do not contribute significantly to the bacterial in vitro mutagenicity of CS TPM. PMID:26724587

  20. Evolutionarily Distinct BAHD N-Acyltransferases Are Responsible for Natural Variation of Aromatic Amine Conjugates in Rice.

    PubMed

    Peng, Meng; Gao, Yanqiang; Chen, Wei; Wang, Wensheng; Shen, Shuangqian; Shi, Jian; Wang, Cheng; Zhang, Yu; Zou, Li; Wang, Shouchuang; Wan, Jian; Liu, Xianqing; Gong, Liang; Luo, Jie

    2016-07-01

    Phenolamides (PAs) are specialized (secondary) metabolites mainly synthesized by BAHD N-acyltransferases. Here, we report metabolic profiling coupled with association and linkage mapping of 11 PAs in rice (Oryza sativa). We identified 22 loci affecting PAs in leaves and 16 loci affecting PAs in seeds. We identified eight BAHD N-acyltransferases located on five chromosomes with diverse specificities, including four aromatic amine N-acyltransferases. We show that genetic variation in PAs is determined, at least in part, by allelic variation in the tissue specificity of expression of the BAHD genes responsible for their biosynthesis. Tryptamine hydroxycinnamoyl transferase 1/2 (Os-THT1/2) and tryptamine benzoyl transferase 1/2 (Os-TBT1/2) were found to be bifunctional tryptamine/tyramine N-acyltransferases. The specificity of Os-THT1 and Os-TBT1 for agmatine involved four tandem arginine residues, which have not been identified as specificity determinants for other plant BAHD transferases, illustrating the versatility of plant BAHD transferases in acquiring new acyl acceptor specificities. With phylogenetic analysis, we identified both divergent and convergent evolution of N-acyltransferases in plants, and we suggest that the BAHD family of tryptamine/tyramine N-acyltransferases evolved conservatively in monocots, especially in Gramineae. Our work demonstrates that omics-assisted gene-to-metabolite analysis provides a useful tool for bulk gene identification and crop genetic improvement. PMID:27354554

  1. Evolutionarily Distinct BAHD N-Acyltransferases Are Responsible for Natural Variation of Aromatic Amine Conjugates in Rice[OPEN

    PubMed Central

    Peng, Meng; Chen, Wei; Wang, Wensheng; Shen, Shuangqian; Shi, Jian; Wang, Cheng; Zhang, Yu; Zou, Li; Wang, Shouchuang; Wan, Jian; Liu, Xianqing; Gong, Liang; Luo, Jie

    2016-01-01

    Phenolamides (PAs) are specialized (secondary) metabolites mainly synthesized by BAHD N-acyltransferases. Here, we report metabolic profiling coupled with association and linkage mapping of 11 PAs in rice (Oryza sativa). We identified 22 loci affecting PAs in leaves and 16 loci affecting PAs in seeds. We identified eight BAHD N-acyltransferases located on five chromosomes with diverse specificities, including four aromatic amine N-acyltransferases. We show that genetic variation in PAs is determined, at least in part, by allelic variation in the tissue specificity of expression of the BAHD genes responsible for their biosynthesis. Tryptamine hydroxycinnamoyl transferase 1/2 (Os-THT1/2) and tryptamine benzoyl transferase 1/2 (Os-TBT1/2) were found to be bifunctional tryptamine/tyramine N-acyltransferases. The specificity of Os-THT1 and Os-TBT1 for agmatine involved four tandem arginine residues, which have not been identified as specificity determinants for other plant BAHD transferases, illustrating the versatility of plant BAHD transferases in acquiring new acyl acceptor specificities. With phylogenetic analysis, we identified both divergent and convergent evolution of N-acyltransferases in plants, and we suggest that the BAHD family of tryptamine/tyramine N-acyltransferases evolved conservatively in monocots, especially in Gramineae. Our work demonstrates that omics-assisted gene-to-metabolite analysis provides a useful tool for bulk gene identification and crop genetic improvement. PMID:27354554

  2. Heterocyclic aromatic amines in deep fried lamb meat: The influence of spices marination and sensory quality.

    PubMed

    S, Jinap; Iqbal, Shahzad Zafar; Talib, Nur Hafiza; Hasnol, N D S

    2016-03-01

    The present study was focused to investigate the effect of selected spices (turmeric, torch ginger, lemongrass and curry leaves) on the formation of heterocyclic amines (HCAs, IQx, MeIQ, MeIQx, DiMeIQx, IQ, harman, norharman, and AαC) in deep fried lamb meat. Meat samples were marinated with optimized levels of turmeric (4 %), 10 % each of torch ginger, lemon grass, curry leaves at medium (70 °C) and well done (80 °C) doneness temperatures. The concentration of HCAs in deep fried meat samples were analysed using LC-MS/MS technique. The results revealed that torch ginger (10 %) has reduced 74.8 % of Me1Qx (1.39 to 0.35 ng/g) at medium doneness, followed by the 64.7 % reduction, using curry leaves and turmeric at medium degree of doneness. Torch ginger has reduced 86.6 % of AαC (2.59 to 0.40 ng/g) at well done doneness. The most prevalence level of HCAs was found in deep fried meat i.e. DiMeIQ (3.69 ng/g) at well done doneness. The sensory evaluation, using a 7 point hedonic test design for colour and texture in deep fried meat samples were resulted in a preferred color of golden brown and slightly tough texture. The use of local spices in marinating of deep fried lamb meat samples will certainly inhibit/reduce the level of these toxic and harmful HCAs. PMID:27570265

  3. B···π-aromatic and C-H···B interactions in co-crystals of aromatic amine N-oxides with p-phenylenediboronic acid

    NASA Astrophysics Data System (ADS)

    Sarma, Rupam; Baruah, Jubaraj Bikash

    2009-02-01

    Co-crystals of p-phenylenediboronic acid with four aromatic N-oxides namely pyridine N-oxide, quinoline N, N'-dioxide, isoquinoline N, N'-dioxide and 4,4'-dipyridine N, N'-dioxide are prepared and are structurally characterized. The stacking pattern in each case is found to be different. An interesting stacking effect that, sandwiches the boronic acid groups by pyridine N-oxide rings and associated through η2 and η3 type B-π interactions is presented. In the structures of co-crystals of aromatic amine N-oxides with p-phenylenediboronic acid B···π aromatic and C-H···B interactions are observed.

  4. Determination of Aromatic Amines Using Solid-Phase Microextraction Based on an Ionic Liquid-Mediated Sol-Gel Technique.

    PubMed

    Abbasi, Vajihe; Sarafraz-Yazdi, Ali; Amiri, Amirhassan; Vatani, Hossein

    2016-04-01

    A headspace solid-phase microextraction (HS-SPME) method was developed for isolation of monocyclic aromatic amines from water samples followed by gas chromatography-flame ionization detector (GC-FID). In this work, the effect of the presence of ionic liquid (namely, 1-hexyl-3-methyl-imidazolium hexafluorophosphate [C6MIM][PF6]) was investigated in the sol-gel coating solutions on the morphology and extraction behavior of the resulting hybrid organic-inorganic sol-gel sorbents utilized in SPME. Hydroxy-terminated poly(dimethylsiloxane) (PDMS) was used as the sol-gel active organic component for sol-gel hybrid coatings. Two different coated fibers that were prepared are PDMS and PDMS-IL ([C6MIM][PF6]) fibers. Under the optimal conditions, the method detection limits (S/N = 3) with PDMS-IL were in the range of 0.001-0.1 ng/mL and the limits of quantification (S/N = 10) between 0.005 and 0.5 ng/mL. The relative standard deviations for one fiber (n = 5) were obtained from 3.1 up to 8.5% and between fibers or batch to batch (n = 3) in the range of 5.3-10.1%. The developed method was successfully applied to real water and juice fruits samples while the relative recovery percentages obtained for the spiked water samples at 0.1 ng/mL were from 83.3 to 95.0%. PMID:26759488

  5. Activation of the aryl hydrocarbon receptor by carcinogenic aromatic amines and modulatory effects of their N-acetylated metabolites.

    PubMed

    Juricek, Ludmila; Bui, Linh-Chi; Busi, Florent; Pierre, Stéphane; Guyot, Erwan; Lamouri, Aazdine; Dupret, Jean-Marie; Barouki, Robert; Coumoul, Xavier; Rodrigues-Lima, Fernando

    2015-12-01

    Aromatic amines (AAs) are an important class of chemicals which account for 12 % of known carcinogens. The biological effects of AAs depend mainly on their biotransformation into reactive metabolites or into N-acetylated metabolites which are generally considered as less toxic. Although the activation of the aryl hydrocarbon receptor (AhR) pathway by certain carcinogenic AAs has been reported, the effects of their N-acetylated metabolites on the AhR have not been addressed. Here, we investigated whether carcinogenic AAs and their N-acetylated metabolites may activate/modulate the AhR pathway in the absence and/or the presence of a bona fide AhR ligand (benzo[a]pyrene/B(a)P]. In agreement with previous studies, we found that certain AAs activated the AhR in human liver and lung cells as assessed by an increase in cytochrome P450 1A1 (CYP1A1) expression and activity. Altogether, we report for the first time that these properties can be modulated by the N-acetylation status of the AA. Whereas 2-naphthylamine significantly activated the AhR and induced CYP1A1 expression, its N-acetylated metabolite was less efficient. In contrast, the N-acetylated metabolite of 2-aminofluorene was able to significantly activate AhR, whereas the parent AA, 2-aminofluorene, did not. In the presence of B(a)P, activation of AhR or antagonist effects were observed depending on the AA or its N-acetylated metabolite. Activation and/or modulation of the AhR pathway by AAs and their N-acetylated metabolites may represent a novel mechanism contributing to the toxicological effects of AAs. More broadly, our data suggest biological interactions between AAs and other classes of xenobiotics through the AhR pathway. PMID:25224404

  6. [Rapid analysis of 28 primary aromatic amines in aqueous food simulants by high performance liquid chromatography-tandem mass spectrometry].

    PubMed

    Xiao, Xiaofeng; Wang, Jianling; Yang, Juanjuan; Liu, Tingfei; Chen, Tong; He, Jun; Deng, Hongyi; Gao, Qiyan

    2013-01-01

    A novel method for rapid analysis of the migration amounts of 28 primary aromatic amines (PAAs) in aqueous food simulants (10% ethanol, 30 g/L acetic acid and 20% ethanol aqueous solution) was developed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After the migration test, the soaking solution was cooled down from 100 degrees C, vortexed, filtered through a hydrophilic polytetrafluoroethylene filter with a disposable syringe, and then the filtrate was analyzed by HPLC-MS/MS. A Zorbax SB-Phenyl column (250 mm x 4.6 mm, 5 microm) was selected for chromatography. The mobile phase consisted of water and 0.1% formic acid-25% acetonitrile-methanol solution with gradient elution. The 28 PAAs in aqueous food simulants were detected by tandem mass spectrometer operated in positive electrospray ionization (ESI+) and multiple reaction monitoring (MRM) mode. The limits of quantification for the 28 PAAs were between 0.002 microg/L and 10 microg/L. The linearity of the method was good with correlation coefficients (r2) greater than 0.995 over the concentration range from 5 microg/L or 10 microg/L to 100 microg/L. The average recoveries of the 28 PAAs were between 76.6% and 114% with the relative standard deviations between 1.53% and 8.97% at the levels of 10, 20, and 40 microg/L. The method shows rapid pretreatment, the lower limits of quantification, good recoveries and accuracies, and meets the requirement of European Union (EU) No 10/2011 regulation for the specific migration of PAAs. The method has been applied to analyze the 28 PAAs in different aqueous food simulants from the migration test of 30 batches of food contact material samples exported to EU. PMID:23667988

  7. Combined ion-pair extraction and gas chromatography-mass spectrometry for the simultaneous determination of diamines, polyamines and aromatic amines in Port wine and grape juice.

    PubMed

    Fernandes, J O; Ferreira, M A

    2000-07-21

    An accurate and very sensitive method which allows for the simultaneous determination of the diamines (1,3-diaminopropane, putrescine and cadaverine), of the polyamines (spermidine and spermine), and of the aromatic amines (beta-phenylethylamine and tyramine) found in Port wines and corresponding grape juices is presented. Sample clean-up consisted of the extraction of the amines with the ion-pairing reagent bis-2-ethylhexylphosphate dissolved in chloroform followed by a back-extraction with 0.1 M HCl. The hydrochloric extract obtained was dried and the amines were further derivatized with heptafluorobutyric anhydride and analyzed by GC-MS in the selected ion-monitoring mode, with a total run time of 18 min. Under the adopted conditions, the extraction of all the studied compounds was almost complete and the obtained extracts were free of potential interferents present in the samples, namely sugars, and most of the amino acids and polyphenols. Via the use of a set of five selected internal standards (amphetamine, [2H8]putrescine, 1,7-diaminoheptane, norspermidine and norspermine), the data obtained from the linearity, repeatability and recovery experiments were very good for all the compounds assayed. The corresponding limits of detection were invariably below 10 microg l(-1). The method was successfully applied to measure the content of biogenic amines in twelve young and five aged Port wine samples, eleven grape juice samples as well as in ten Portuguese red and white table wines. Results are presented and briefly discussed. PMID:10950286

  8. Conversion to isothiocyanates via dithiocarbamates for the determination of aromatic primary amines by headspace-solid phase microextraction and gas chromatography.

    PubMed

    Jain, Archana; Reddy-Noone, Kishan; Pillai, Aradhana K K V; Verma, Krishna K

    2013-11-01

    A novel and highly selective method has been developed for the determination of aromatic primary amines by their conversion to dithiocarbamates by reaction with carbon disulphide, and then to isothiocyanates, which are volatile, by heating in the presence of a heavy metal ion. Zinc(II) was selected owing to its low toxicity and optimum yield of isothiocyanates. The latter were sampled by headspace-solid phase microextraction (HS-SPME) on divinylbenzene-carboxen-polydimethylsiloxane fibre, 50/30 μm. The HS-SPME procedure was optimized to provide adequate limits of detection in the analysis of aromatic amines in their real samples by gas chromatography with mass spectrometry (GC-MS) or flame ionization detection (GC-FID). The method gave rectilinear calibration graph, correlation coefficient and limit of detection, respectively, over the range 0.08-100 μg L(-1), 0.9950-0.9990 and 25-240 ng L(-1) in gas chromatography-mass spectrometry, and 0.01-10 mg L(-1), 0.9910-0.9991 and 0.8-3.0 μg L(-1) in gas chromatography-flame ionization detection. At two different levels, 10 and 40 μg L(-1), the range of intra-day RSD was 3.7-8.5% (GC-MS) and 3.3-9.2% (GC-FID), respectively. The proposed method is simple and rapid, and has been applied to determine aromatic primary amines in the environmental waters, food samples of ice cream powder and soft drinks concentrate, and food colours. The intra-day RSD in the analysis of real samples by GC-MS was in the range 3.6-6.2%. The food/colour samples were found to contain elevated levels of aniline and 2-toluidine. PMID:24139574

  9. Binding of aromatic amines to the rat hepatic Ah receptor in vitro and in vivo and the 8S and 4S estrogen receptor of rat uterus and rat liver

    SciTech Connect

    Cikryt, P.; Kaiser, T.; Gottlicher, M. )

    1990-08-01

    Studies on structurally related aromatic amines with different carcinogenic properties have shown that 2-acetylaminofluorene (2-AAF) and 2-acetylaminophenanthrene (AAP) inhibit the binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin to the Ah receptor in vitro. The apparent inhibitor constants (K{sub i}) are 2.3 {mu}M for 2-AAF and 2.7 {mu}M for AAP. In contrast, 4-acetylaminofluorene, an isomer of 2-AAF, and trans-4-acetylaminostilbene do not bind to the rat hepatic cytosolic Ah receptor. Pretreating female Wistar rats with 2-AAF or AAP leads to the induction of the P-450 isoenzymes that are under the control of the Ah receptor. Ornithine decarboxylase activity is induced by all aromatic amines tested irrespective of their Ah receptor affinity. The aromatic amines used as model compounds do not inhibit the binding of 17-{beta}-estradiol to the 8S and 4S estrogen receptor of rat uterus or rat liver in a competition assay analyzed using sucrose density gradient centrifugation. On the other hand, the aromatic amines bind to varying extents to another estrogen-binding protein of rat liver whose function and identity is still unknown. The study demonstrates that structurally related aromatic amines in their unmetabolized form interact differentially with a cellular target protein, the Ah receptor, in vitro as well as in vivo. However, a relationship between these effects and the postulated promoting properties of 2-AAF remains to be established.

  10. Brønsted acid mediated N-O bond cleavage for α-amination of ketones through the aromatic nitroso aldol reaction.

    PubMed

    Ramakrishna, Isai; Sahoo, Harekrishna; Baidya, Mahiuddin

    2016-02-11

    A Brønsted acid mediated N-O bond cleavage for α-amination of ketones has been developed through the nitroso aldol reaction of less-reactive aromatic nitroso compounds and silyl enol ethers having a disilane (-SiMe2TMS) backbone. This transformation is operationally simple and scalable, offering structurally diverse α-amino ketones in high yields (up to 98%) with complete regioselectivity. It represents a mechanistically unique and rare example of a metal-free N-O bond cleavage process. PMID:26810365

  11. Kinetics of the reactions of the acid anhydrides with aromatic amines in aprotic solvents. M.S. Thesis. Final Report

    NASA Technical Reports Server (NTRS)

    Sugg, E.; Mason, J. G.

    1983-01-01

    Work has revealed that diamine derivatives of diphenylmethane (IV), diphenyl ether (V), benzophenone (IV), fluorene (VII), and fluorenone (VIII) polymerizations with pyromellitic dianhydride in DMA were dependent on the basicity of the amine compound. The correlation between the basicity of the amine and its reactivity with phthalic anhydride was determined. Basicity measurements were made by potentiometric titration of each amine in an acetonitrile-water solvent system, from which the pKa of the amine could be determined. Reactivity was defined in terms of the second order rate constant derived form spectrophotometric examination of the reaction between each amine and phthalic anhydride in DMA. This reaction was expected to proceed in either one (for a monoamine) or two (for a diamine) stages.

  12. Regioselective ortho Amination of Coordinated 2-(Arylazo)pyridine. Isolation of Monoradical Palladium Complexes of a New Series of Azo-Aromatic Pincer Ligands.

    PubMed

    Sengupta, Debabrata; Chowdhury, Nabanita Saha; Samanta, Subhas; Ghosh, Pradip; Seth, Saikat Kumar; Demeshko, Serhiy; Meyer, Franc; Goswami, Sreebrata

    2015-12-01

    In an unusual reaction of [Pd(L(1))Cl2] (L(1) = 2-(arylazo)pyridine) with amines, a new series of palladium complexes [Pd(L(2•-))Cl] (L(2) = 2-((2-amino)arylazo)pyridine) (1a-1h) were isolated. The complexes were formed via N-H and N-C bond cleavage reactions of 1°/2° and 3° amines, respectively, followed by regioselective aromatic ortho-C-N bond formation reaction and are associated with ortho-C-H/ortho-C-Cl bond activation. A large variety of amines including both aromatic and aliphatic were found to be effective in producing air-stable complexes. Identity of the resultant complexes was confirmed by their X-ray structure determination. Efforts were also made to understand the mechanism of the reaction. A series of experiments were performed, which point toward initial ligand reduction followed by intraligand electron transfer. Examination of the structural parameters of these complexes (1) indicates that the in situ generated ligand coordinated to the Pd(II) center serves as the backbone of these air-stable monoradical complexes. Molecular and electronic structures of the isolated complexes were further scrutinized by various spectroscopic techniques including cyclic voltammetry, variable temperature magnetic susceptibility measurements, electron paramagnetic resonance, and UV-vis spectroscopy. Finally the electronic structure was confirmed by density functional theory calculations. The isolated monoradical complexes adopt an unusual π-stacked array, which leads to a relatively strong antiferromagnetic interaction (J = -40 cm(-1) for the representative complex 1c). PMID:26562467

  13. Aerobic oxidative amidation of aromatic and cinnamic aldehydes with secondary amines by CuI/2-pyridonate catalytic system.

    PubMed

    Zhu, Mingwen; Fujita, Ken-ichi; Yamaguchi, Ryohei

    2012-10-19

    A simple and convenient CuI/2-pyridonate catalytic system for the oxidative amidation of aldehydes with secondary amines has been developed. With this system, a variety of useful arylamides have been synthesized in moderate to good yields in the presence of small amount of copper catalyst and the pyridonate ligand, generating only water as a coproduct. Synthesis of cinnamamides was also achieved by the reactions of cinnamaldehydes with secondary amines in moderate yields. Air was successfully employed as a green oxidant in this catalytic system, achieving a safe and atom-efficient system for the synthesis of amides. PMID:23006061

  14. 18O incorporation in the oxidation of N-methylcarbazole by lignin peroxidase and a model compound: a mechanistic insight into the oxidative N-demethylation of aromatic tertiary amines.

    PubMed

    Baciocchi, Enrico; Gerini, Maria Francesca; Lapi, Andrea

    2002-05-01

    Using 18O labelled reactants and/or solvent, the origin of the oxygen in the products of the oxidation of N-methylcarbazole by H2O2 catalysed by lignin peroxidase and a model compound has been determined, so getting important information about the mechanism of the oxidative N-demethylation of aromatic tertiary amines. PMID:12123061

  15. Heteroatom speciation in coal liquefaction via FT-IR coupled with liquid chromatography. Quarterly progress report, July 1-September 30, 1983. [Azaarenes and aromatic amines

    SciTech Connect

    Taylor, L.T.

    1983-12-01

    We have chosen high performance liquid chromatography in the normal phase mode for analysis of azaarenes and aromatic amines in coal-derived products. Our mode of detection is on-line Fourier transform infrared spectrometry. This analytical method offers advantages over many GC/MS methods in that nonvolatile material may be handled, derivatization need not be performed prior to analysis and isomer identification is possible. The disadvantages due to sensitivity and mobile phase infrared transparency have been partly addressed by employing microbore columns and deuterated and/or halogenated chromatographic solvents. The use of low flow rates (..mu..L/min) with microbore columns results in low solvent consumption which has advantages with respect to cost and disposal. Microbore columns provide an increase in eluent concentration over analytical scale columns for a similar amount of injected material. 19 references, 11 figures.

  16. Specific determination of 20 primary aromatic amines in aqueous food simulants by liquid chromatography-electrospray ionization-tandem mass spectrometry.

    PubMed

    Mortensen, Sarah Kelly; Trier, Xenia Thorsager; Foverskov, Annie; Petersen, Jens Hójslev

    2005-10-14

    A multi-analyte method without any pre-treatment steps using reversed-phase liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was developed and applied for the determination of 20 primary aromatic amines (PAA) associated with polyurethane (PUR) products or azo-colours. The method was validated in-house for water and 3% acetic acid food simulants using spiked migrates from plastic laminates. Detection limits ranged from 0.27 to 3 microg amine/L food simulants, and RSD values of within-laboratory reproducibility at the 2 microg PAA/L level ranged from 3.9 to 19%. PAA migration from plastic laminates and black nylon cooking utensils were determined with the method, and high levels of 4,4'-methylenedianiline and aniline were found in migrates from about half of the tested cooking utensils. The method fulfils present legislative demands in the EU for screening and verification of PAA migration from food contact materials. PMID:16395791

  17. Determination of total non-sulphonated aromatic amines in soft drinks and hard candies by reduction and derivatization followed by high-performance liquid chromatography.

    PubMed

    Lancaster, F E; Lawrence, J F

    1992-01-01

    Utilizing elements of methodology developed previously for food colours, total free and bound non-sulphonated aromatic amines (NSAA) were determined in commercial samples of soft drink beverages and hard candies. Bound amines in the samples were reduced using sodium dithionite, then total NSAA were extracted into chlorofom, transferred to aqueous acid solution and diazotized with sodium nitrite before coupling with 2-naphthol-3,6-disulphonic acid, disodium salt (R-salt). The coloured derivatives were analysed using reversed-phase ion pair high-performance liquid chromatography (HPLC) and an absorbance detector set at 512 nm. Solid phase extraction cartridges were utilized for extraction and clean-up of the food colours present in the sample, and the concentration of each dye was determined quantitatively using HPLC and absorbance detector wavelengths of 426, 516 or 625 nm. Levels of total NSAA were compatible with those observed previously in food colours. Commercial soft drinks were found to contain (expressed in terms of total free plus bound NSAA in the beverage) 0.19-12.6 ng/ml of aniline, 0.83-8.25 ng/ml 1-naphthylamine and 0.62-1.12 ng/ml 2-naphthylamine. Levels of 0.66-9.15 ng/g of aniline and 2.48-10.6 ng/g 1-naphthylamine were found in commercial samples of hard candies. Bound NSAA in hard candies appeared to survive the manufacturing process. Recoveries averaged 96.9% for tartrazine and 89.6-97.2% for the bound amines when hard candies were prepared in the laboratory. PMID:1499774

  18. Model studies of lignified fiber fermentation by human fecal microbiota and its impact on heterocyclic aromatic amine adsorption

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study examined how shifts in pH and fiber fermentation may alter the adsorption of mutagenic heterocyclic amines (HAAs) 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-9H-pyrido[2,3-b]indole (AaC) to dietary fiber in the human small intestine and colon. Nonlignified and artif...

  19. Comparison of carbon-sulfur and carbon-amine bond in therapeutic drug: 4β-S-aromatic heterocyclic podophyllum derivatives display antitumor activity

    PubMed Central

    Li, Jian-Long; Zhao, Wei; Zhou, Chen; Zhang, Ya-Xuan; Li, Hong-Mei; Tang, Ya-Ling; Liang, Xin-Hua; Chen, Tao; Tang, Ya-Jie

    2015-01-01

    Herein is a first effort to systematically study the significance of carbon-sulfur (C-S) and carbon-amine (C-NH) bonds on the antitumor proliferation activity of podophyllum derivatives and their precise mechanism of apoptosis. Compared with the derivative modified by a C-NH bond, the derivative modified by a C-S bond exhibited superior antitumor activity, the inhibition activity of target proteins tubulin or Topo II, cell cycle arrest, and apoptosis induction. Antitumor mechanistic studies showed that the death receptor and the mitochondrial apoptotic pathways were simultaneously activated by the C-S bond modified aromatic heterocyclic podophyllum derivatives with a higher cellular uptake percentage of 60–90% and induction of a higher level of reactive oxygen species (ROS). Only the mitochondrial apoptotic pathway was activated by the C-NH bond modified aromatic heterocyclic podophyllum derivatives, with a lower cellular uptake percentage of 40–50%. This study provided insight into effects of the C-S and C-NH bond modification on the improvement of the antitumor activity of Podophyllum derivatives. PMID:26443888

  20. Hepatic microsomal mixed-function oxidase activity in ethanol-treated hamsters and its consequences on the bioactivation of aromatic amines to mutagens.

    PubMed

    Ioannides, C; Steele, C M

    1986-09-01

    Male golden Syrian hamsters were maintained on ethanol-containing liquid diets for 4 weeks, corresponding to an average daily intake of 17 g/kg body wt. The p-hydroxylation of aniline was markedly enhanced by this treatment while minimal effects were seen in benzphetamine N-demethylase and ethoxyresorufin O-deethylase activities; there was no change in the microsomal levels of cytochromes P-450. Hepatic microsomal preparations from the ethanol-treated hamsters were more efficient than controls fed isocaloric diets in converting 2-aminofluorene, 4-aminobiphenyl, benzidine and 2-acetylaminofluorene into mutagens in the Salmonella mutagenicity test. The same treatment had no effect on the metabolic activation of 2-naphthylamine and even inhibited the mutagenicity of 2-aminoanthracene. No increase was seen in the activation of the two polycyclic aromatic hydrocarbons, benzo[a]pyrene and 3-methylcholanthrene to mutagens and an inhibitory effect was seen with the former. The ethanol-induced increase in the mutagenicity of 2-aminofluorene was inhibited by 2-butanol but not by the hydroxyl radical scavenger dimethylsulphoxide. It is concluded that chronic ethanol ingestion modulates the bioactivation of aromatic amines and amides to mutagens, the effect being substrate dependent. This effect of ethanol may be catalysed by unique form(s) of cytochrome P-450 whose synthesis is induced by such treatment. PMID:3021347

  1. Reliable liquid chromatography-mass spectrometry method for investigation of primary aromatic amines migration from food packaging and during industrial curing of multilayer plastic laminates.

    PubMed

    Lambertini, Francesca; Di Lallo, Valentina; Catellani, Dante; Mattarozzi, Monica; Careri, Maria; Suman, Michele

    2014-09-01

    Primary aromatic amines (PAAs) can migrate from packaging into food from different sources such as polyurethanic adhesives used for the manufacture of multilayer films, which may contain residual aromatic isocyanates, or recycled paperboard, because of the presence of azo dyes in the printed paper massively used in the recycling process. In the present work, a reliable analytical method, exploiting a conventional high-performance liquid chromatography-(selected ion monitoring)-mass spectrometry system, for PAAs compliance assessment in food contact materials was developed as an effective alternative to the current standard spectrophotometric one, moving in this way from the screening to the accurate and selective quantitation perspective for the analysis of PAAs both in aqueous and acidic food simulants. The main validation parameters were verified achieving very satisfactory results in terms of linearity range, limit of detection (ranging from 0.1 to 1.0 µg kg(-1)) and quantitation (ranging from 0.1 to 3.6 µg kg(-1)), repeatability and accuracy. Suitability of the method was demonstrated for a wide range of commercial samples, chosen among different producers of the most common used food packaging plastic and paperboard categories and then analyzed to assess the risk related to PAAs migration. Finally, the method was also successfully exploited to monitor the evolution of potential PAAs migration during the industrial curing process of multilayer plastic laminates, prior to their release for delivery to the food industry end user. PMID:25230184

  2. Identification of cancer chemopreventive isothiocyanates as direct inhibitors of the arylamine N-acetyltransferase-dependent acetylation and bioactivation of aromatic amine carcinogens

    PubMed Central

    Duval, Romain; Xu, Ximing; Bui, Linh-Chi; Mathieu, Cécile; Petit, Emile; Cariou, Kevin; Dodd, Robert H.; Dupret, Jean-Marie; Rodrigues-Lima, Fernando

    2016-01-01

    Aromatic amines (AAs) are chemicals of industrial, pharmacological and environmental relevance. Certain AAs, such as 4-aminobiphenyl (4-ABP), are human carcinogens that require enzymatic metabolic activation to reactive chemicals to form genotoxic DNA adducts. Arylamine N-acetyltransferases (NAT) are xenobiotic metabolizing enzymes (XME) that play a major role in this carcinogenic bioactivation process. Isothiocyanates (ITCs), including benzyl-ITC (BITC) and phenethyl-ITC (PEITC), are phytochemicals known to have chemopreventive activity against several aromatic carcinogens. In particular, ITCs have been shown to modify the bioactivation and subsequent mutagenicity of carcinogenic AA chemicals such as 4-ABP. However, the molecular and biochemical mechanisms by which these phytochemicals may modulate AA carcinogens bioactivation and AA-DNA damage remains poorly understood. This manuscript provides evidence indicating that ITCs can decrease the metabolic activation of carcinogenic AAs via the irreversible inhibition of NAT enzymes and subsequent alteration of the acetylation of AAs. We demonstrate that BITC and PEITC react with NAT1 and inhibit readily its acetyltransferase activity (ki = 200 M−1.s−1 and 66 M−1.s−1 for BITC and PEITC, respectively). Chemical labeling, docking approaches and substrate protection assays indicated that inhibition of the acetylation of AAs by NAT1 was due to the chemical modification of the enzyme active site cysteine. Moreover, analyses of AAs acetylation and DNA adducts in cells showed that BITC was able to modulate the endogenous acetylation and bioactivation of 4-ABP. In conclusion, we show that direct inhibition of NAT enzymes may be an important mechanism by which ITCs exert their chemopreventive activity towards AA chemicals. PMID:26840026

  3. Identification of cancer chemopreventive isothiocyanates as direct inhibitors of the arylamine N-acetyltransferase-dependent acetylation and bioactivation of aromatic amine carcinogens.

    PubMed

    Duval, Romain; Xu, Ximing; Bui, Linh-Chi; Mathieu, Cécile; Petit, Emile; Cariou, Kevin; Dodd, Robert H; Dupret, Jean-Marie; Rodrigues-Lima, Fernando

    2016-02-23

    Aromatic amines (AAs) are chemicals of industrial, pharmacological and environmental relevance. Certain AAs, such as 4-aminobiphenyl (4-ABP), are human carcinogens that require enzymatic metabolic activation to reactive chemicals to form genotoxic DNA adducts. Arylamine N-acetyltransferases (NAT) are xenobiotic metabolizing enzymes (XME) that play a major role in this carcinogenic bioactivation process. Isothiocyanates (ITCs), including benzyl-ITC (BITC) and phenethyl-ITC (PEITC), are phytochemicals known to have chemopreventive activity against several aromatic carcinogens. In particular, ITCs have been shown to modify the bioactivation and subsequent mutagenicity of carcinogenic AA chemicals such as 4-ABP. However, the molecular and biochemical mechanisms by which these phytochemicals may modulate AA carcinogens bioactivation and AA-DNA damage remains poorly understood.This manuscript provides evidence indicating that ITCs can decrease the metabolic activation of carcinogenic AAs via the irreversible inhibition of NAT enzymes and subsequent alteration of the acetylation of AAs. We demonstrate that BITC and PEITC react with NAT1 and inhibit readily its acetyltransferase activity (ki = 200 M-1.s-1 and 66 M-1.s-1 for BITC and PEITC, respectively). Chemical labeling, docking approaches and substrate protection assays indicated that inhibition of the acetylation of AAs by NAT1 was due to the chemical modification of the enzyme active site cysteine. Moreover, analyses of AAs acetylation and DNA adducts in cells showed that BITC was able to modulate the endogenous acetylation and bioactivation of 4-ABP. In conclusion, we show that direct inhibition of NAT enzymes may be an important mechanism by which ITCs exert their chemopreventive activity towards AA chemicals. PMID:26840026

  4. Cadmium Alters the Biotransformation of Carcinogenic Aromatic Amines by Arylamine N-Acetyltransferase Xenobiotic-Metabolizing Enzymes: Molecular, Cellular, and in Vivo Studies

    PubMed Central

    Ragunathan, Nilusha; Dairou, Julien; Sanfins, Elodie; Busi, Florent; Noll, Christophe; Janel, Nathalie; Dupret, Jean-Marie; Rodrigues-Lima, Fernando

    2010-01-01

    Background Cadmium (Cd) is a carcinogenic heavy metal of environmental concern. Exposure to both Cd and carcinogenic organic compounds, such as polycyclic aromatic hydrocarbons or aromatic amines (AAs), is a common environmental problem. Human arylamine N-acetyltransferases (NATs) are xenobiotic-metabolizing enzymes that play a key role in the biotransformation of AA carcinogens. Changes in NAT activity have long been associated with variations in susceptibility to different cancers in relation with exposure to certain AAs. Objective We explored the possible interactions between Cd and the NAT-dependent biotransformation of carcinogenic AAs. Methods We exposed purified enzymes, lung epithelial cells, and mouse models to Cd and subsequently analyzed NAT-dependent metabolism of AAs. Results We found that Cd, at biologically relevant concentrations, impairs the NAT-dependent acetylation of carcinogenic AAs such as 2-aminofluorene (2-AF) in lung epithelial cells. NAT activity was strongly impaired in the tissues of mice exposed to Cd. Accordingly, mice exposed to Cd and 2-AF displayed altered in vivo toxicokinetics with a significant decrease (~ 50%) in acetylated 2-AF in plasma. We found that human NAT1 was rapidly and irreversibly inhibited by Cd [median inhibitory concentration (IC50) ≈ 55 nM; rate inhibition constant (kinact) = 5 × 104 M−1 · sec−1], with results of acetyl coenzyme A (acetyl-CoA) protection assays indicating that Cd-mediated inhibition was due to the reaction of metal with the active-site cysteine residue of the enzyme. We found similar results for human NAT2, although this isoform was less sensitive to inactivation (IC50 ≈ 1 μM; kinact = 1 × 104 M−1 · sec−1). Conclusions Our data suggest that Cd can alter the metabolism of carcinogenic AAs through the impairment of the NAT-dependent pathway, which may have important toxicological consequences. PMID:20810355

  5. A comparative study of lysosome-targetable pH probes based on phenoxazinium attached with aliphatic and aromatic amines.

    PubMed

    Wang, Xiu-Li; Li, Xiao-Jun; Sun, Ru; Xu, Yu-Jie; Ge, Jian-Feng

    2016-05-10

    In this paper, phenoxazinium was used as a fluorophore for the design of pH probes by the photoinduced electron transfer (PET) mechanism. Phenoxazinium with an aliphatic morpholinyl group (probe ) gave increased emission at 665 nm with pH ranging from 7.4 to 4.4; meanwhile, the other one with an aromatic diethylaminophenyl group (probe ) gave nearly OFF-ON emission at 679 nm with pH ranging from 7.4 to 4.2. They both were reversible pH probes with good selectivity. Their optical properties, especially the PET mechanism, were illustrated by (TD)DFT theory. Fluorescence confocal imaging of probes and a typical phenoxazinium dye (Oxazine 1) was also performed, and the results indicated that probes are lysosome-targetable biomarkers. PMID:27048759

  6. Formation of Heterocyclic Aromatic Amines and Migration Level of Bisphenol-A in Sous-Vide-Cooked Trout Fillets at Different Cooking Temperatures and Cooking Levels.

    PubMed

    Oz, Fatih; Seyyar, Esra

    2016-04-20

    The effects of different cooking temperatures (65, 75, and 85 °C) and cooking levels (medium and well) on some quality properties, the formation of heterocyclic aromatic amines (HCAs), and the migration level of bisphenol-A (BPA) in trout fillets cooked by sous-vide were investigated. As a result, as expected, cooking caused a reduction in water content of the samples, whereas pH, TBARS, L*, and b* values increased. Cooking loss values ranged between 14.78 and 20.51%. Whereas IQ, MeIQ, 7,8-DiMeIQx, 4,8-DiMeIQx, PhIP, AαC and MeAαC could not be detected in the analyzed samples, varying levels of IQx (up to 0.16 ng/g) and MeIQx (up to 5.66 ng/g) were detected. It was determined that total HCA amounts ranged between 1.28 and 5.75 ng/g, and all or a big part of the total HCAs belonged to MeIQx. In addition, the migration level of BPA in sous-vide-cooked samples ranged between 4.93 and 27.11 ng/g. PMID:27029998

  7. Mechanism of error-free and semitargeted mutagenic bypass of an aromatic amine lesion by Y-family polymerase Dpo4

    SciTech Connect

    Rechkoblit, Olga; Kolbanovskiy, Alexander; Malinina, Lucy; Geacintov, Nicholas E.; Broyde, Suse; Patel, Dinshaw J.

    2010-03-30

    The aromatic amine carcinogen 2-aminofluorene (AF) forms covalent adducts with DNA, predominantly with guanine at the C8 position. Such lesions are bypassed by Y-family polymerases such as Dpo4 via error-free and error-prone mechanisms. We show that Dpo4 catalyzes elongation from a correct 3{prime}-terminal cytosine opposite [AF]G in a nonrepetitive template sequence with low efficiency. This extension leads to cognate full-length product, as well as mis-elongated products containing base mutations and deletions. Crystal structures of the Dpo4 ternary complex, with the 3{prime}-terminal primer cytosine base opposite [AF]G in the anti conformation and with the AF moiety positioned in the major groove, reveal both accurate and misalignment-mediated mutagenic extension pathways. The mutagenic template-primer-dNTP arrangement is promoted by interactions between the polymerase and the bulky lesion rather than by a base pair-stabilized misaligment. Further extension leads to semitargeted mutations via this proposed polymerase-guided mechanism.

  8. Determination of urinary aromatic amines in smokers and nonsmokers using a MIPs-SPE coupled with LC-MS/MS method.

    PubMed

    Yu, Jingjing; Wang, Sheng; Zhao, Ge; Wang, Bing; Ding, Li; Zhang, Xiaobing; Xie, Jianping; Xie, Fuwei

    2014-05-01

    Urinary aromatic amines (AAs) could be used as biomarkers for human exposure to AAs in cigarette smoke. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of urinary AAs (i.e. 1-naphthylamine (1-NA), 2-naphthylamine (2-NA), 3-aminobiphenyl (3-ABP) and 4-aminobiphenyl (4-ABP)) in smokers and nonsmokers. A molecularly imprinted polymers (MIPs) solid phase extraction (SPE) cartridge was applied to purify urine samples and no derivatization reaction was involved. Each analytes used respective stable isotope internal standards, which could well compensate matrix effect. Lower limit of detections (LODs) for four AAs were obtained and in the range of 1.5-5ngL(-1). Recovery ranged from 87.7±4.5% to 111.3±6.4% and precision were less than 9.9%. The method was applied to analyze urine samples of 40 smokers and 10 nonsmokers. The 24h urinary excretion amounts of total AAs were higher for smokers compared with nonsmokers. What's more, 1-NA, 3-ABP and 4-ABP excretion amounts showed significant differences (p<0.05) between smokers and nonsmokers. PMID:24735928

  9. Aromatic amines from polyurethane adhesives in food packaging: the challenge of identification and pattern recognition using Quadrupole-Time of Flight-Mass SpectrometryE.

    PubMed

    Pezo, Davinson; Fedeli, Mauro; Bosetti, Osvaldo; Nerín, Cristina

    2012-12-01

    Toxic primary aromatic amines (PAAs) are reaction products from residual isocyanates in polyurethane adhesives. The maximum migration level of the total sum of PAAs is 10 ng g(-1) of food. This paper reports on a method for quantification of 18 PAAs by UHPLC-MS/MS that was optimised and applied to a series of industrial laminates prepared from polyurethane adhesives. Non-intentionally added substances (NIAS), impurities and other migrants were identified by Q-TOF/MS(E). A comparison of the quantitative values obtained by the colorimetric method using NEDA and by UHPLC-MS/MS confirmed that the first method can overestimate the quantification of PAAs. This could be attributed to the impurities and other NIAS present in the plastic laminate. Values of R(2) in the analytical characteristics of UHPLC-MS/MS were obtained, the best value being 0.9964 and the most unfavourable 0.7626. The detection limit (LOD) and the quantification limit (LOQ) were 2 pg g(-1) and 7 pg g(-1), respectively. The stability of the PAAs over time in the acidic simulant in contact with the plastic laminate is also reported. PMID:23176739

  10. [Characterization of cases contravening of regulations regarding primary aromatic amines originating from azo dyes in commercial textile products and leather products in European Union].

    PubMed

    Kawakami, Tsuyoshi; Isama, Kazuo; Ikarashi, Yoshiaki

    2013-01-01

    Contraventions of regulations regarding primary aromatic amines (PAAs) originating from azo dyes in commercial textile products and leather products in European Union (EU), notified in the period between 2006 and 2012 were collected from the Rapid Alert System for non-food consumer products (RAPEX), were characterized. Various types of products (clothes, footwear, bedding, etc.) and their raw materials (cotton, silk, viscose, leather, etc.) were reported to have contravened the regulations. The contravention frequencies for products made in China and India were higher than those for other countries. Ten percentage of the country in which the reported products were produced was unknown. The notification frequencies for benzidine and 4-aminoazobenzene were higher than those for other PAAs. Contravention of regulations regarding benzidine, 4-aminoazobenzene, and 3,3'-dimethoxybenzidine were notified every year. Contraventions of regulations regarding five PAAs--classified as IARC group 1--were notified one or several times. Since the scale of the survey conducted in Japan were small compared with RAPEX, it is necessary that many kinds and number of products should be surveyed in Japan. In addition, it is also necessary to pay attention to 4-aminoazobenzene, while it has not been detected in the previous studies conducted in Japan. PMID:24340672

  11. [Applications of multi-micro-volume pressure-assisted derivatization reaction device for analysis of polar heterocyclic aromatic amines by gas chromatography-mass spectrometry].

    PubMed

    Wang, Yiru; Chen, Fangxiang; Shi, Yamei; Tan, Connieal; Chen, Xi

    2013-01-01

    A multi-micro-volume pressure-assisted derivatization reaction device has been designed and made for the silylation derivatization of polar heterocyclic aromatic amines by N-(tert-butyldimethylsilyl )-N-methyl-trifluoroacetamide (MTBSTFA) with 1% catalyst tert-butyldimethylchlorosilane (TBDMCS) at a high temperature. The tert-butyldimethylsilyl derivatives then could be automatically analyzed by gas chromatography-mass spectrometry. Using the pressure-assisted device, the silylation reaction may occur at a temperature higher than the boiling points of the reagents, and several micro-volume samples can be simultaneously pretreated in the same device to shorten the sample-preparation time and to improve the repeatability. The derivatization conditions including the headspace volume of the vial, the evaporative surface area of the reagent, derivatization temperature and time have been discussed for the use of the pressure-assisted device. The experimental results proved that the device is an effective way for the simultaneous derivatization of several micro-volume samples at a high temperature. Compared with a common device, the derivative amounts were obviously increased when using the pressure-assisted device at 90 degrees C. Quantitative derivatization can be achieved even at 150 degrees C while there was no common device could be applied at such a high temperature due to the heavy losses of reagents by evaporation. However, no obviously higher reaction speed has been observed in such a circumstance with a higher temperature and a higher pressure using the pressure-assisted device. PMID:23667982

  12. The presence of aliphatic and aromatic amines in reservoir and canal water as precursors to disinfection by-products.

    PubMed

    Phatthalung, Warangkana Na; Musikavong, Charongpun; Suttinun, Oramas

    2016-09-18

    This research aimed at determining the dimethylamine (DMA), diethylamine (DEA), dibutylamine (DBA), and aromatic aniline (AN) in reservoir and canal water in the U-Tapao River Basin, Songkhla, Thailand. The trihalomethane formation potential (THMFP) and N-nitrosodimethylamine formation potential (NDMA-FP) of the reservoir and canal water were analyzed. Water samples from two reservoirs and raw water from water treatment plants at upstream, midstream, and downstream locations of the canal were collected twice. The analysis of the DMA, DEA, DBA, and AN were conducted using gas chromatography and spectrofluorometry techniques. The DMA, DEA, and DBA levels in the reservoir and canal waters ranged from not detectable (ND) to 10 µg/L and from ND to 21.2 µg/L, respectively. AN was detected from 123 to 129 ng/L and from 112 to 177 ng/L in the reservoir and canal waters, respectively. The DMA, DEA, DBA, and AN exhibited two fluorescent peaks at 230nmEx/345nmEm and 280 nmEx/355nmEm. These two peaks corresponded to the peak positions of tryptophan. Detection limits of DMA, DEA, and DBA for fluorescent analysis were 500 μg/L whereas that of AN and tryptophan were 10 and 0.5 μg/L, respectively. The NDMA-FP measured in all the water samples was lower than the detection limit of 237 ng/L. THMFP ranged from 175 to 248 μg/L and 214 to 429 μg/L was detected in the reservoir and canal waters, respectively. The THMFP/dissolved organic carbon (DOC) of the reservoir and canal waters were comparable within the ranges of 73 to 131 µg THMFP/mg DOC. PMID:27314493

  13. Determination of primary aromatic amines in cold water extract of coloured paper napkin samples by liquid chromatography-tandem mass spectrometry.

    PubMed

    Yavuz, Oguzhan; Valzacchi, Sandro; Hoekstra, Eddo; Simoneau, Catherine

    2016-06-01

    The aim of this study was the optimisation of a multi-analyte method for the analysis of primary aromatic amines (PAAs) from napkins in order to support official controls and food safety. We developed a UHPLC-MS/MS method for the simultaneous determination of 36 toxicologically relevant PAAs for paper and board. Good regression coefficients of the calibration curves in a range of 0.992-0.999 and reproducibilities in a range of 2.3-15% were obtained. Limits of detections (LODs) were in the range of 0.03-1.4 µg l(-1) and recoveries were in a range of 21-110% for all the amines. A total of 93 coloured paper napkin samples from different European countries were bought and extracted with water to determine the PAAs. The results showed that 42 of 93 samples contained at least one PAA. More than half of the detected PAAs are considered as toxic, carcinogenic or probably carcinogenic to humans by the International Agency for Research on Cancer (IARC), or are classified as such in the European Union legislation on chemicals. Summed concentrations of PAAs in seven samples were higher than 10 µg l(-1), the limit of summed PAA in the European Union plastic food contact material regulation. Also, eight PAAs, classified as Category 1A and 1B carcinogen in the European Union legislation of chemicals, were detected at concentrations higher than 2 µg l(-1), exceeding the limit proposed by the Federal Institute for Risk Assessment in Germany. Aniline (n = 14) was most frequently present in higher concentrations followed by o-toluidine, o-anisidine, 2,4-dimethylaniline and 4-aminoazobenzene. Red, orange, yellow and multicoloured paper napkins contained the highest concentrations of total PAAs (> 10 µg l(-1)). Although the European Union has not harmonised the legislation of paper and board materials and, thus, there is no specific migration limit for PAAs from paper napkins, the present study showed that coloured paper napkins can contain toxic and carcinogenic PAAs at

  14. Determination of primary aromatic amines in cold water extract of coloured paper napkin samples by liquid chromatography-tandem mass spectrometry

    PubMed Central

    Yavuz, Oguzhan; Valzacchi, Sandro; Hoekstra, Eddo; Simoneau, Catherine

    2016-01-01

    ABSTRACT The aim of this study was the optimisation of a multi-analyte method for the analysis of primary aromatic amines (PAAs) from napkins in order to support official controls and food safety. We developed a UHPLC-MS/MS method for the simultaneous determination of 36 toxicologically relevant PAAs for paper and board. Good regression coefficients of the calibration curves in a range of 0.992–0.999 and reproducibilities in a range of 2.3–15% were obtained. Limits of detections (LODs) were in the range of 0.03–1.4 µg l–1 and recoveries were in a range of 21–110% for all the amines. A total of 93 coloured paper napkin samples from different European countries were bought and extracted with water to determine the PAAs. The results showed that 42 of 93 samples contained at least one PAA. More than half of the detected PAAs are considered as toxic, carcinogenic or probably carcinogenic to humans by the International Agency for Research on Cancer (IARC), or are classified as such in the European Union legislation on chemicals. Summed concentrations of PAAs in seven samples were higher than 10 µg l–1, the limit of summed PAA in the European Union plastic food contact material regulation. Also, eight PAAs, classified as Category 1A and 1B carcinogen in the European Union legislation of chemicals, were detected at concentrations higher than 2 µg l–1, exceeding the limit proposed by the Federal Institute for Risk Assessment in Germany. Aniline (n = 14) was most frequently present in higher concentrations followed by o-toluidine, o-anisidine, 2,4-dimethylaniline and 4-aminoazobenzene. Red, orange, yellow and multicoloured paper napkins contained the highest concentrations of total PAAs (> 10 µg l–1). Although the European Union has not harmonised the legislation of paper and board materials and, thus, there is no specific migration limit for PAAs from paper napkins, the present study showed that coloured paper napkins can contain toxic and

  15. Magnetic solid-phase extraction using poly(para-phenylenediamine) modified with magnetic nanoparticles as adsorbent for analysis of monocyclic aromatic amines in water and urine samples.

    PubMed

    Amiri, Amirhassan; Baghayeri, Mehdi; Nori, Somayeh

    2015-10-01

    In the present work, a simple and effective method based on magnetic separation has been developed for the extraction of monocyclic aromatic amines in water and urine samples using poly(para-phenylenediamine) modified with Fe3O4 nanoparticles (PpPD/Fe3O4) as an adsorbent. The chemical structures of the sorbent were characterized by field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectrophotometer (FT-IR). Various parameters affecting on the extraction efficiency of desired analytes, such as pH of solution, desorption conditions, extraction time, salt effect and amount of adsorbent have been investigated and optimized. The obtained optimal conditions were: sample pH, 6; amount of sorbent, 20mg; sorption time, 2min; elution solvent and its volume, dichloromethane and chloroform (3:1 v/v), 250μL; elution time, 30s and without addition of NaCl. Under the optimum conditions, detection limits in the range of 0.007-0.01ngmL(-1) were obtained by gas chromatography-flame ionization detector (GC-FID). The calibration curves were linear in the range 0.05-100ngmL(-1) with a correlation coefficient better than 0.9953. In addition, a satisfactory reproducibility was achieved by evaluating the intra- and inter-day precisions with relative standard deviations (RSDs) less than 5.9 and 7.3%, respectively. The proposed procedure has been successfully applied to the determination of target analytes in water and urine samples. The results demonstrated that the developed method is simple, inexpensive, accurate and remarkably free from interference effects. PMID:26341590

  16. Preferential induction of the AhR gene battery in HepaRG cells after a single or repeated exposure to heterocyclic aromatic amines

    SciTech Connect

    Dumont, Julie Josse, Rozenn Lambert, Carine Antherieu, Sebastien Laurent, Veronique Loyer, Pascal Robin, Marie-Anne Guillouzo, Andre

    2010-11-15

    2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) are two of the most common heterocyclic aromatic amines (HAA) produced during cooking of meat, fish and poultry. Both HAA produce different tumor profiles in rodents and are suspected to be carcinogenic in humans. In order to better understand the molecular basis of HAA toxicity, we have analyzed gene expression profiles in the metabolically competent human HepaRG cells using pangenomic oligonucleotide microarrays, after either a single (24-h) or a repeated (28-day) exposure to 10 {mu}M PhIP or MeIQx. The most responsive genes to both HAA were downstream targets of the arylhydrocarbon receptor (AhR): CYP1A1 and CYP1A2 after both time points and CYP1B1 and ALDH3A1 after 28 days. Accordingly, CYP1A1/1A2 induction in HAA-treated HepaRG cells was prevented by chemical inhibition or small interference RNA-mediated down-regulation of the AhR. Consistently, HAA induced activity of the CYP1A1 promoter, which contains a consensus AhR-related xenobiotic-responsive element (XRE). In addition, several other genes exhibited both time-dependent and compound-specific expression changes with, however, a smaller magnitude than previously reported for the prototypical AhR target genes. These changes concerned genes mainly related to cell growth and proliferation, apoptosis, and cancer. In conclusion, these results identify the AhR gene battery as the preferential target of PhIP and MeIQx in HepaRG cells and further support the hypothesis that intake of HAA in diet might increase human cancer risk.

  17. Simultaneous conduction of two- and three-phase hollow-fiber-based liquid-phase microextraction for the determination of aromatic amines in environmental water samples.

    PubMed

    Tao, Yong; Liu, Jing-Fu; Wang, Thanh; Jiang, Gui-Bin

    2009-01-30

    This paper describes a simultaneously performed two-/three-phase hollow-fiber-based liquid-phase microextraction (HF-LPME) method for the determination of aromatic amines with a wide range of pK(a) (-4.25 to 4.6) and logK(OW) (0.9-2.8) values in environmental water samples. Analytes including aniline, 4-nitroaniline, 2,4-dinitroaniline and dicloran were extracted from basic aqueous samples (donor phase, DP) into the microliter volume of organic membrane phase impregnated into the pores of the polypropylene hollow fiber wall, then back extracted into the acidified aqueous solution (acceptor phase, AP) filling in the lumen of the hollow fiber. The mass transfer of the analytes from the donor phase through the organic membrane phase into acceptor phase was driven by both the counter-coupled transport of hydrogen ions and the pH gradient. Afterwards, the hollow fiber was eluted with 50 microL methanol to capture the analytes from both the organic membrane and the acceptor phase. Factors relevant to the enrichment factors (EFs) were investigated. Under the optimized condition (DP: 100 mL of 0.1 M NaOH with 2 M Na(2)SO(4); organic phase: di-n-hexyl with 8% trioctylphosphine oxide (TOPO); AP: 10 microL of 8 M HCl; extraction time of 80 min), the obtained EFs were 405-2000, dynamic linear ranges were 5-200 microg/L (R>0.9976), and limits of detection were 0.5-1.5 microg/L. The presence of humic acid (0-25 mg/L dissolved organic carbon) had no significant effect on the extraction efficiency. The proposed procedure worked very well for real environmental water samples with microgram per liter level of analytes, and good spike recoveries (80-103%) were obtained. PMID:19108841

  18. Thermochromic organometallic complexes: experimental and theoretical studies of 16- to 18-electron interconversions of adducts of arene Ru(II) carboranes with aromatic amine ligands.

    PubMed

    Barry, Nicolas P E; Deeth, Robert J; Clarkson, Guy J; Prokes, Ivan; Sadler, Peter J

    2013-02-21

    A series of 18-electron complexes of general formula [Ru(p-cym)(1,2-dicarba-closo-dodecaborane-1,2-dithiolato)(L)] (p-cym = para-cymene; L = 4-dimethylaminopyridine (2), nicotinamide (3), 3-ethynylpyridine (4), N-methylimidazole (5), 4-cyanopyridine (6), and pyridine (7)) were synthesised by reactions between the 16-electron precursor [Ru(p-cym)(1,2-dicarba-closo-dodecaborane-1,2-dithiolato)] (1) and corresponding heterocyclic bases. X-ray crystal structures of complexes 2 and 5 were determined. In dichloromethane and chloroform solutions at ambient temperature, the 18-electron complexes 2-7 are in equilibrium with the 16-electron precursor 1. Each equilibrium is displaced towards the formation of the blue 16-electron or yellow 18-electron complex by increasing or decreasing the temperature of the solution, respectively, which results in controlled and reversible thermochromism. Binding constants (K) and Gibbs free energies (ΔG°) of the six equilibria have been determined by a combination of experiments (Job plots, UV-visible titrations, NMR studies) and also by computation (time-dependent density functional theory, TD-DFT). A linear free energy relationship for log K versus pK(a) for the pyridine and imidazole ligands was established. The predicted strong interactions of 1 with other aromatic amine ligands, such as amphetamine derivatives, were verified experimentally. This appears to be the first report of reversible 16/18-electron interconversions with associated thermochromic properties for a well-known family of complexes. PMID:23223796

  19. Acid-labile protein-adducted heterocyclic aromatic amines in human blood are not viable biomarkers of dietary exposure: A systematic study.

    PubMed

    Cooper, Kevin M; Brennan, Sarah F; Woodside, Jayne V; Cantwell, Marie; Guo, Xiaoxiao; Mooney, Mark; Elliott, Christopher T; Cuskelly, Geraldine J

    2016-05-01

    Heterocyclic aromatic amines (HCA) are carcinogenic mutagens formed during cooking of protein-rich foods. HCA residues adducted to blood proteins have been postulated as biomarkers of HCA exposure. However, the viability of quantifying HCAs following hydrolytic release from adducts in vivo and correlation with dietary intake are unproven. To definitively assess the potential of labile HCA-protein adducts as biomarkers, a highly sensitive UPLC-MS/MS method was validated for four major HCAs: 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) and 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline (7,8-DiMeIQx). Limits of detection were 1-5 pg/ml plasma and recoveries 91-115%. Efficacy of hydrolysis was demonstrated by HCA-protein adducts synthesised in vitro. Plasma and 7-day food diaries were collected from 122 fasting adults consuming their habitual diets. Estimated HCA intakes ranged from 0 to 2.5 mg/day. An extensive range of hydrolysis conditions was examined for release of adducted HCAs in plasma. HCA was detected in only one sample (PhIP, 9.7 pg/ml), demonstrating conclusively for the first time that acid-labile HCA adducts do not reflect dietary HCA intake and are present at such low concentrations that they are not feasible biomarkers of exposure. Identification of biomarkers remains important. The search should concentrate on stabilised HCA-peptide markers and use of untargeted proteomic and metabolomic approaches. PMID:26993956

  20. Sensitive Detection of Aromatic Hydrophobic Compounds in Water and Perfluorooctane Sulfonate in Human Serum by Surface-Assisted Laser Desorption/Ionization Mass Spectrometry (SALDI-MS) with Amine Functionalized Graphene-Coated Cobalt Nanoparticles

    PubMed Central

    Nakai, Keisuke; Kawasaki, Hideya; Yamamoto, Atsushi; Arakawa, Ryuichi; Grass, Robert N.; Stark, Wendelin J.

    2014-01-01

    In this article, we describe the application of surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) with the use of amine functionalized graphene-coated cobalt nanoparticles (CoC–NH2 nanoparticles) to analyse aromatic hydrophobic compounds that are known environmental contaminants, including polycyclic aromatic hydrocarbons (PAHs) and pentachlorophenol (PCP). Our results demonstrated that SALDI-MS can detect PCP, anthracene, and pyrene in water. In particular, the CoC–NH2 nanoparticles proved to be an efficient means of capturing PCP in water because of the high adsorption capacity of the nanoparticles for PCP, which resulted in a detectability of 100 ppt. Furthermore, the CoC–NH2 nanoparticles also functioned as an adsorbent for solid-phase extraction of perfluorooctane sulfonate (PFOS) from human serum, displaying good performance with a detectability of 10 ppb by SALDI-MS. PMID:26819871

  1. Evaluation of the in vivo genotoxic potential of three carcinogenic aromatic amines using the Big Blue{trademark} transgenic mouse mutation assay

    SciTech Connect

    Suter, W.; Ahiabor, R.; Blanco, B.

    1996-12-31

    Three genotoxic mouse carcinogens, 4-chloro-o-phenylenediamine (4-C-o-PDA), 2-nitro-p-phenylenediamine (2-N-p-PDA), and 2,4-diaminotoluene (2,4-DAT), were tested in the Big Blue{trademark} transgenic mouse mutation assay. Each experiment consisted of a vehicle control group with ten Big Blue{trademark} C57BL/6 mice, five of either sex, and an equally sized group treated with a high dose of the test chemical. In addition, four animals were treated with the vehicle and six animals with the test compound for the measurement of bromodeoxyuridine (BrdU) incorporation to determine cellular proliferation. The doses used in the main study were 200 mg/kg/day for 4-C-o-PDA, 150 mg/kg/day for 2-N-p-PDA, and 80 mg/kg/day for 2,4-DAT. There was no increase in BrdU incorporation immediately after treatment with 4-C-o-PDA or with 2,4-DAT. However, 10 days after the last treatment with 2,4-DAT, a strong mitogenic effect was found with both techniques. 4-C-o-PDA, a liver carcinogen in both genders of mice, induced a small, statistically significant increase of the mutant frequencies in females, none in males. 2-N-p-PDA was found positive in males and was clearly negative in females. 2,4-DAT, a liver carcinogen in female mice, was positive in females and negative in males when the animals were killed 10 days after the last treatment. After an expression time of 28 days, 2,4-DAT induced a statistically significant increase in both sexes. The effect in females was marginally stronger than after 10 days` expression time and almost identical to the effect observed in makes under these test conditions. In conclusion, the experiments showed that the Big Blue{trademark} assay detects the genotoxicity of the three carcinogenic monocyclic aromatic amines tested. However, it seems that the sex specificity of the carcinogenic effects of these compounds is not reflected by the mutagenicity data in Big Blue{trademark} mice. 39 refs., 6 tabs.

  2. The biochemistry of aromatic amines

    PubMed Central

    Boyland, E.; Manson, D.

    1966-01-01

    1. 2-Naphthylhydroxylamine and 2-nitrosonaphthalene were present in urine of dogs but not of guinea pigs, hamsters, rabbits or rats dosed with 2-naphthylamine. N-Acetyl-2-naphthylhydroxylamine and its O-sulphonic acid and O-glucosiduronic acid were not detected in the urine of any of these species. 2. Bile from rats dosed with 2-naphthylamine contained (2-naphthylamine N-glucosid)uronic acid and 6- and 5,6-substituted derivatives of 2-acetamidonaphthalene. 2-Amino-1-naphthyl and 2-acetamido-1-naphthyl derivatives, 2-naphthylhydroxylamine and its N-acetyl derivative or conjugates of these were not detected. Bile from a dog dosed with 2-naphthylamine contained no 2-amino-1-naphthyl derivatives. 3. 2-Naphthylhydroxylamine was metabolized by the dog, rat and guinea pig to the same products as those formed by these species from 2-naphthylamine. Rabbits formed mainly 2-amino-1-naphthyl derivatives; these are minor metabolites of 2-naphthylamine in this species. 4. (N-Acetyl-2-naphthylhydroxylamine O-glucosid)uronic acid was excreted in the urine and the bile of rats and in the urine of guinea pigs and rabbits dosed with N-acetyl-2-naphthylhydroxylamine. 5. After the administration of 2-acetamidonaphthalene, (N-acetyl-2-naphthylhydroxylamine O-glucosid)uronic acid was detected in the urine of dogs, but not in the urine of other species. The dog excreted an acid-labile cysteine derivative of 2-acetamidonaphthalene, but only traces of the corresponding mercapturic acid. 6. After dosing with N-acetyl-2-naphthylhydroxylamine-O-sulphonic acid, rats excreted derivatives of 2-amino-1-naphthol. 7. 2-Nitrosonaphthalene, N-acetyl-2-naphthylhydroxylamine, N-acetyl-2-naphthylhydroxylamine-O-sulphonic acid, 2-naphthylhydroxylamine-N-sulphonic acid, N-benzyloxycarbonyl-2-naphthylhydroxylamine and N-benzyloxycarbonyl-2-naphthylhydroxylamine-O-sulphonic acid were synthesized. PMID:5971797

  3. The reaction of primary aromatic amines with alkylene carbonates for the selective synthesis of bis-N-(2-hydroxy)alkylanilines: the catalytic effect of phosphonium-based ionic liquids.

    PubMed

    Selva, Maurizio; Fabris, Massimo; Lucchini, Vittorio; Perosa, Alvise; Noè, Marco

    2010-11-21

    At T≥ 140 °C, different primary aromatic amines (pX-C(6)H(4)NH(2); X = H, OCH(3), CH(3), Cl) react with both ethylene- and propylene-carbonates to yield a chemoselective N-alkylation process: bis-N-(2-hydroxyalkyl)anilines [pX-C(6)H(4)N(CH(2)CH(R)OH)(2); R = H, CH(3)] are the major products and the competitive formation of carbamates is substantially ruled out. At 140 °C, under solventless conditions, the model reaction of aniline with ethylene carbonate goes to completion by simply mixing stoichiometric amounts of the reagents. However, a class of phosphonium ionic liquids (PILs) such as tetraalkylphosphonium halides and tosylates turn out to be active organocatalysts for both aniline and other primary aromatic amines. A kinetic analysis monitored by (13)C NMR spectroscopy, shows that bromide exchanged PILs are the most efficient systems, able to impart a more than 8-fold acceleration to the reaction. The reactions of propylene carbonate take place at a higher temperature than those of ethylene carbonate, and only in the presence of PIL catalysts. A mechanism based on the Lewis acidity of tetraalkylphosphonium cations and the nucleophilicity of halide anions has been proposed to account for both the reaction chemoselectivity and the function of the catalysts. PMID:20844790

  4. The Caffeine Cytochrome P450 1A2 Metabolic Phenotype Does Not Predict the Metabolism of Heterocyclic Aromatic Amines in Humans

    PubMed Central

    Turesky, Robert J.; White, Kami K.; Wilkens, Lynne R.; Marchand, Loïc Le

    2015-01-01

    2-Amino-1-methylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) are carcinogenic heterocyclic aromatic amines (HAAs) formed in well-done cooked meats. Chemicals that induce cytochrome P450 (P450) 1A2, a major enzyme involved in the bioactivation of HAAs, also form in cooked meat. Therefore, well-done cooked meat may pose an increase in cancer risk because it contains both inducers of P450 1A2 and procarcinogenic HAAs. We examined the influence of components in meat to modulate P450 1A2 activity and the metabolism of PhIP and MeIQx in volunteers during a 4 week feeding study of well-done cooked beef. The mean P450 1A2 activity, assessed by caffeine metabolic phenotyping, ranged from 6.3 to 7.1 before the feeding study commenced and from 9.6 to 10.4 during the meat feeding period: the difference in means was significant (P < 0.001). Unaltered PhIP, MeIQx, and their P450 1A2 metabolites, N2-(β-1-glucosiduronyl-2-(hydroxyamino)-1-methyl-6-phenylimidazo[4,5-b]pyridine (HON-PhIP-N2-Gl); N3-(β-1-glucosiduronyl-2-(hydroxyamino)-1-methyl-6-phenylimidazo[4,5-b]pyridine (HON-PhIP-N3-Gl); 2-amino-3-methylimidazo-[4,5-f]quinoxaline-8-carboxylic acid (IQx-8-COOH); and 2-amino-8-(hydroxymethyl)-3-methylimidazo[4,5-f]quinoxaline (8-CH2OH-IQx) were measured in urine during days 2, 14, and 28 days of the meat diet. Significant correlations were observed on these days between the levels of the unaltered HAAs and their oxidized metabolites, when expressed as percent of dose ingested or as metabolic ratios. However, there was no statistically significant correlation between the caffeine P450 1A2 phenotype and any urinary HAA biomarker. Although the P450 1A2 activity varied by greater than 20-fold among the subjects, there was a large intra-individual variation of the P450 1A2 phenotype and inconsistent responses to inducers of P450 1A2. The coefficient of variation of the P450 1A2 phenotype within-individual ranged between 1 to 112% (median=40

  5. Bifunctional tertiary amine-squaramide catalyzed asymmetric catalytic 1,6-conjugate addition/aromatization of para-quinone methides with oxindoles.

    PubMed

    Deng, Yu-Hua; Zhang, Xiang-Zhi; Yu, Ke-Yin; Yan, Xu; Du, Ji-Yuan; Huang, Hanmin; Fan, Chun-An

    2016-03-01

    The asymmetric catalytic 1,6-addition of p-QMs with racemic oxindoles under the bifunctional catalysis of C2-symmetric dimeric Cinchona-derived squaramide is described. This tertiary amine-squaramide catalyzed reaction provides a diastereoselective and enantioselective approach to the effective assembly of diverse diarylmethine-substituted oxindoles having vicinal tertiary and quaternary stereocenters. PMID:26908307

  6. Chemoselective Reductive Amination of Carbonyl Compounds for the Synthesis of Tertiary Amines Using SnCl2·2H2O/PMHS/MeOH.

    PubMed

    Nayal, Onkar S; Bhatt, Vinod; Sharma, Sushila; Kumar, Neeraj

    2015-06-01

    Stannous chloride catalyzed chemoselective reductive amination of a variety of carbonyl compounds with aromatic amines has been developed for the synthesis of a diverse range of tertiary amines using inexpensive polymethylhydrosiloxane as reducing agent in methanol. The present method is also applicable for the synthesis of secondary amines including heterocyclic ones. PMID:25938581

  7. The carcinogenic effect of aromatic amines: an epidemiological study on the role of o-toluidine and 4,4'-methylene bis (2-methylaniline) in inducing bladder cancer in man

    SciTech Connect

    Rubino, G.F.; Scansetti, G.; Piolatto, G.; Pira, E.

    1982-04-01

    Cause-specific mortality of 906 workers first employed 1922-1970 in a dyestuff factory in Northern Italy was compared to national figures: a marked excess of bladder cancer was observed (36 observed vs 1.23 expected deaths). The mean latent period was 25 years. The excess was higher among those with longer duration of exposure. Some excess of mortality from lung cancer, laryngeal cancer, and esophageal cancer was also found, but a clear explanation could not be provided regarding the causal role of aromatic amines. Mortality from bladder cancer was very much higher among those exposed in benzidine and naphthylamines manufacture as compared to those only exposed in use or intermittent contact. Excess bladder cancer was also very high among workers in fuchsin manufacture. There is evidence that o-toluidine and 4,4'-methylene bis(2-methylaniline) should be implicated in such excess mortality. Caution in handling these compounds is therefore suggested and the need for further studies to confirm such findings is stressed.

  8. Evaluation and application of microwave-assisted extraction and dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for the determination of polar heterocyclic aromatic amines in hamburger patties.

    PubMed

    Aeenehvand, Saeed; Toudehrousta, Zahra; Kamankesh, Marzieh; Mashayekh, Morteza; Tavakoli, Hamid Reza; Mohammadi, Abdorreza

    2016-01-01

    This study developed an analytical method based on microwave-assisted extraction and dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for the determination of three polar heterocyclic aromatic amines from hamburger patties. Effective parameters controlling the performance of the microextraction process, such as the type and volume of extraction and disperser solvents, microwave time, nature of alkaline aqueous solution, pH and salt amount, were optimized. The calibration graphs were linear in the range of 1-200 ng g(-1), with a coefficient of determination (R(2)) better than 0.9993. The relative standard deviations (RSD) for seven analyses were between 3.2% and 6.5%. The recoveries of those compounds in hamburger patties were from 90% to 105%. Detection limits were between 0.06 and 0.21 ng g(-1). A comparison of the proposed method with the existing literature demonstrates that it is a simple, rapid, highly selective and sensitive, and it gives good enrichment factors and detection limits for determining HAAs in real hamburger patties samples. PMID:26212992

  9. Impact of Precursors Creatine, Creatinine, and Glucose on the Formation of Heterocyclic Aromatic Amines in Grilled Patties of Various Animal Species.

    PubMed

    Gibis, Monika; Weiss, Jochen

    2015-11-01

    The impact of precursors such as creatine, creatinine, and glucose on the formation of mutagenic/carcinogenic heterocyclic amines (HAs) were studied in patties of 9 different animal species equally heat treated with a double-plate contact grill. All grilled patties of the various species (veal, beef, pork, lamb, horse, venison, turkey, chicken, ostrich) contained several HAs such as MeIQx (2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline; 0.5-1.4 ng/g), 4,8-DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f] quinoxaline, 0 to 1.3 ng/g), PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine, 1.2 to 10.5 ng/g), harman (1-methyl-9H-pyrido[3,4-b] indole; 0.5 to 3.2 ng/g), and/or norharman (9H-pyrido[3,4-b]indole 0.5 to 1.9 ng/g). Residual glycogen (glucose) content varied greatly from 0.07 to 1.46 wt% on a dry matter (DM) basis. Total creatin(in)e content in raw meat (1.36 to 2.0 wt% DM) hardly differed between species, except in turkey and ostrich (1.1 wt% DM). Chicken contained, compared to all other species, very low concentrations of glucose (0.07 wt% DM) and the highest levels of nonprotein nitrogen compounds. The free amino acids lysine (r = 0.77, P < 0.001), tyrosine, phenylalanine, proline, isoleucine, and aspartic acid (r = 0.47-0.56, P < 0.05) showed significant correlation to PhIP in chicken. Also a linear correlation was found to exist between PhIP (r = 0.87, P < 0.001) and MeIQx (r = 0.35, P < 0.01), and the molar ratio of creatin(in)e to glucose, respectively. Harman as co-mutagens was linearly correlated to the concentration of glucose (r = 0.65, P < 0.001). By contrast, norharman was not significant correlated to glucose levels. PMID:26445401

  10. Metabolic activation of N-hydroxy arylamines, N-hydroxy heterocyclic amines and ring-hydroxymethyl polycyclic aromatic hydrocarbons by human sulfotransferases

    SciTech Connect

    Chou, H.C.

    1993-01-01

    Arylamines and polycyclic aromatic hydrocarbons (PAHs) are two major classes of chemical carcinogens. N-Hydroxylation of arylamines is regarded to be a necessary process for their mutagenicity and carcinogenicity, while alkyl-hydroxylation is the major metabolic pathway for alkyl-substituted PAHs. Evidence has been presented that sulfation of several N-hydroxy arylamines and hydroxymethyl PAHs is an important pathway leading to the formation of ultimate carcinogens in experiment animals. Sulfation of these chemicals forms putative sulfuric acid ester intermediates that can rearrange to electrophilic nitrenium or carbenium ions capable of forming covalent adducts with important cellular macromolecules. In order to study the metabolic activation by sulfotransferase(s) in various human tissue preparations an in vitro enzymatic assay was established. A metabolic phenotyping method was also developed for thermostable phenolsulfotransferase (TS-PST) in platelet homogenates (correlated with TS-PST activity in other tissues) based on a simple colorimetric assay using 2-naphthol as substrate. By using a PAPS-regenerating system to supply the activated sulfate and calf thymus DNA to trap the reactive metabolites, we found that N-hydroxy derivatives of the carcinogens, 4-aminobiphenyl (4-ABP), 4,4[prime]-methylene-bis(2-chloroaniline) (MOCA), 2-acetylaminofluorene (2-AAF), 2-aminofluorene (2-AF), 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP), and 2-amino-6-methyldipyrido [1,2-1:3[prime],2[prime]-d]imidazole (Glu-P-1) were metabolically activated by human TS-PST. On the other hand, three methyl-hydroxylated derivatives (7-OH, 12-OH, and 7,12-diOH) of 7, 12-dimethylbenz[a]anthracene (DMBA) were metabolically activated by human steroid sulfotransferase. Human sulfotransferase(s)-mediated activation of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) or 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) was not observed.

  11. Cobalt-Catalyzed N-Alkylation of Amines with Alcohols.

    PubMed

    Zhang, Guoqi; Yin, Zhiwei; Zheng, Shengping

    2016-01-15

    A well-defined nonprecious metal cobalt(II) catalyst based on a pincer PNP ligand has been employed for the efficient N-alkylation of both aromatic and aliphatic amines with alcohols. A subtle change of reaction conditions (simply adding 4 Å molecular sieves) was observed to readily switch the resulting products (amines vs imines) with high chemoselectivity. A range of alcohols and amines including both aromatic and aliphatic substrates were efficiently converted to secondary amines in good-to-excellent yields when 2 mol % cobalt catalyst was used. Additional experiments indicate that a hydrogen-borrowing mechanism is responsible for the tandem acceptorless dehydrogenation/condensation/hydrogenation process. PMID:26695594

  12. Rapid and simultaneous analysis of ten aromatic amines in mainstream cigarette smoke by liquid chromatography/electrospray ionization tandem mass spectrometry under ISO and "Health Canada intensive" machine smoking regimens.

    PubMed

    Xie, Fuwei; Yu, Jingjing; Wang, Sheng; Zhao, Ge; Xia, Qiaoling; Zhang, Xiaobing; Zhang, Shusheng

    2013-10-15

    Ten primary aromatic amines (AAs) in mainstream cigarette smoke under both ISO and "Health Canada intensive" machine smoking regimens were determined in this work, which were suspected to be carcinogenic compounds. The measured AAs included aniline, ortho-toluidine, meta-toluidine, para-toluidine, 1-naphthylamine, 2-naphthylamine, 3-aminobiphenyl, 4-aminobiphenyl, meta-phenylenediamine and meta-anisidine. For rapidly and sensitively analyzing these AAs, a liquid chromatography-electrospray ionization tandem mass spectrometric (LC-MS/MS) method coupled with solid phase extraction (SPE) was developed. The particulate phase of mainstream cigarette smoke was collected on a Cambridge filter pads, while the gas phase was trapped by 25 mL 5% HCl solution. Then, the pad was extracted in an ultrasonic bath with the impinger HCl solution. After being neutralized with NaOH, the extract was purified with a HLB solid phase extraction column, and then was analyzed with LC-MS/MS using isotope-labeled internal standard. The overall sample pretreatment and analysis time was less than 1.5h. The limits of detection for all targets ranged from 0.05 ng cig(-1) to 0.96 ng cig(-1) with the recoveries in the range of 75.0-131.8%. And the intra-day and inter-day precisions were less than 10% and 16%, respectively. Under HCI machine smoking regimen, the AAs yields in mainstream cigarette smoke were much higher and the average increases were greater than 100% compared with those under ISO smoking condition. PMID:24054615

  13. Asymmetric synthesis of cyclic indole aminals via 1,3-stereoinduction.

    PubMed

    Li, Hongmei; Chen, Cheng-yi; Nguyen, Hoa; Cohen, Ryan; Maligres, Peter E; Yasuda, Nobuyoshi; Mangion, Ian; Zavialov, Ilia; Reibarkh, Mikhail; Chung, John Y L

    2014-09-19

    A general and efficient asymmetric synthesis of cyclic indoline aminals was developed with a high level of 1,3-stereoinduction through a dynamic crystallization-driven condensation. Dehydrogenation of the indoline aminals with potassium permanganate produced the corresponding cyclic indole aminals in high yields and excellent enantioselectivities. This general methodology was successfully applied to the synthesis of a wide variety of chiral cyclic indoline aminals and indole aminals with aromatic and aliphatic functional groups. PMID:25162915

  14. Oxidative nucleophilic aromatic amination of nitrobenzenes.

    PubMed

    Khutorianskyi, V V; Sonawane, M; Pošta, M; Klepetářová, B; Beier, P

    2016-06-01

    Nitrobenzenes substituted with electron-acceptor groups such as halogen, nitro, trifluoromethyl, pentafluorosulfanyl, or cyano underwent oxidative nucleophilic substitution with lithium salts of arylamines to afford N-aryl-2-nitroanilines. PMID:27152372

  15. The Synthesis of Methyl Salicylate: Amine Diazotization.

    ERIC Educational Resources Information Center

    Zanger, Murray; McKee, James R.

    1988-01-01

    Notes that this experiment takes safety and noncarcinogenic reactants into account. Demonstrates the use of diazonium salts for the replacement of an aromatic amine group by a phenolic hydroxyl. Involves two pleasant-smelling organic compounds, methyl anthranilate (grape) and methyl salicylate (oil of wintergreen). (MVL)

  16. Phenylethynyl amine

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Bryant, Robert G. (Inventor); Jensen, Brian J. (Inventor); Havens, Stephen J. (Inventor)

    1997-01-01

    Four phenylethynyl amine compounds--3 and 4-aminophenoxy-4'-phenylethynylbenzophenone, and 3 and 4-amino-4'-phenylethynylbenzophenone--were readily prepared and were used to endcap imide oligomers. Phenylethynyl-terminated amide acid oligomers and phenylethynyl-terminated imide oligomers with various molecular weights and compositions were prepared and characterized. These oligomers were cured at 300.degree. C. to 400.degree. C. to provide crosslinked polyimides with excellent solvent resistance, high strength and modulus and good high temperature properties. Adhesive panels, composites, films and moldings from these phenylethynyl terminated imide oligomers gave excellent mechanical performance.

  17. EVIDENCE FOR THE PRESENCE OF MUTAGENIC ARYL AMINES IN HUMAN BREAST MILK AND DNA ADDUCTS IN EXFOLIATED BREAST-DUCT EPITHELIAL CELLS

    EPA Science Inventory

    Aromatic (AA) and heterocyclic amines (HAA) are ubiquitous environmental mutagens present in combustions emissions, fried meats, tobacco smoke, etc., and are suspect human mammary carcinogens. To determine the presence of aryl amines in breast tissue and fluid, we examined exfol...

  18. Copper-catalyzed N-arylation of amines with part-per-million catalyst loadings under air at room temperature.

    PubMed

    Xie, Ruilong; Fu, Hua; Ling, Yun

    2011-08-21

    An efficient copper-catalyzed method for N-arylation of amines has been developed with part-per-million catalyst loadings at room temperature under air. Reactions of substituted (E)-1-(2-halophenyl)alkanone oximes with aliphatic amines or aromatic amines provided the N-arylation products in good to excellent yields. PMID:21727962

  19. A General Method for Aminoquinoline-Directed, Copper-Catalyzed sp(2) C-H Bond Amination.

    PubMed

    Roane, James; Daugulis, Olafs

    2016-04-01

    An operationally simple and general method for copper-catalyzed, aminoquinoline-assisted amination of β-C(sp(2))-H bonds of benzoic acid derivatives is reported. The reaction employs Cu(OAc)2 or (CuOH)2CO3 catalysts, an amine coupling partner, and oxygen from air as a terminal oxidant. Exceptionally high generality with respect to amine coupling partners is observed. Specifically, primary and secondary aliphatic and aromatic amines, heterocycles, such as indoles, pyrazole, and carbazole, sulfonamides, as well as electron-deficient aromatic and heteroaromatic amines are competent coupling components. PMID:26990413

  20. Identifying a Highly Active Copper Catalyst for KA(2) Reaction of Aromatic Ketones.

    PubMed

    Cai, Yujuan; Tang, Xinjun; Ma, Shengming

    2016-02-12

    The well-established A(3) coupling reaction of terminal alkynes, aldehydes, and amines provides the most straightforward approach to propargylic amines. However, the related reaction of ketones, especially aromatic ketones, is still a significant challenge. A highly efficient catalytic protocol has been developed for the coupling of aromatic ketones with amines and terminal alkynes, in which Cu(I) , generated in situ from the reduction of CuBr2 with sodium ascorbate, has been identified as the highly efficient catalyst. Since propargylic amines are versatile synthetic intermediates and important units in pharmaceutical products, such an advance will greatly stimulate research interest involving the previously unavailable propargylic amines. PMID:26660459

  1. Secondary amines containing one aromatic nitro group: preparation, nitrosation, sustained nitric oxide release, and the synergistic effects of released nitric oxide and an arginase inhibitor on vascular smooth muscle cell proliferation.

    PubMed

    Curtis, Brandon; Payne, Thomas J; Ash, David E; Mohanty, Dillip K

    2013-03-01

    Atherosclerosis, a leading cause of death worldwide, is associated with the excessive proliferation of vascular smooth muscle cells. Nitrogen monoxide, more commonly known as nitric oxide, inhibits this uncontrolled proliferation. Herein we report the preparation of two families of nitric oxide donors; beginning with the syntheses of secondary amine precursors, obtained through the reaction between 2 equiv of various monoamines with 2,4 or 2,6-difluoronitrobenzene. The purified secondary amines were nitrosated then subjected to a Griess reagent test to examine the slow and sustained nitric oxide release rate for each compound in both the absence and presence of reduced glutathione. The release rate profiles of these two isomeric families of NO-donors were strongly dependent on the number of side chain methylene units and the relative orientations of the nitro groups with respect to the N-nitroso moieties. The nitrosated compounds were then added to human aortic smooth muscle cell cultures, individually and in tandem with S-2-amino-6-boronic acid (ABH), a potent arginase inhibitor. Cell viability studies indicated a lack of toxicity of the amine precursors, in addition to anti-proliferative effects exhibited by the nitrosated compounds, which were enhanced in the presence of ABH. PMID:23375096

  2. Solvent-free functionalization of carbon nanotube buckypaper with amines

    NASA Astrophysics Data System (ADS)

    Basiuk, Elena V.; Ramírez-Calera, Itzel J.; Meza-Laguna, Victor; Abarca-Morales, Edgar; Pérez-Rey, Luis A.; Re, Marilena; Prete, Paola; Lovergine, Nico; Álvarez-Zauco, Edgar; Basiuk, Vladimir A.

    2015-12-01

    We demonstrate the possibility of fast and efficient solvent-free functionalization of buckypaper (BP) mats prefabricated from oxidized multiwalled carbon nanotubes (MWCNTs-ox), by using three representative amines of different structure: one monofunctional aliphatic amine, octadecylamine (ODA), one monofunctional aromatic amine, 1-aminopyrene (AP), and one aromatic diamine, 1,5-diaminonaphthalene (DAN). The functionalization procedure, which relies on the formation of amide bonds with carboxylic groups of MWCNTs-ox, is performed at 150-180 °C under reduced pressure and takes about 4 h including auxiliary degassing. The amine-treated BP samples (BP-ODA, BP-AP and BP-DAN, respectively) were characterized by means of a variety of analytical techniques such as Fourier-transform infrared and Raman spectroscopy, thermogravimetric and differential thermal analysis, scanning and transmission electron microscopy, scanning helium ion microscopy, and atomic force microscopy. The highest amine content was found for BP-ODA, and the lowest one was observed for BP-DAN, with a possible contribution of non-covalently bonded amine molecules in all three cases. Despite of some differences in spectral and morphological characteristics for amine-functionalized BP samples, they have in common a dramatically increased stability in water as compared to pristine BP and, on the other hand, a relatively invariable electrical conductivity.

  3. Effect of donor orientation on ultrafast intermolecular electron transfer in coumarin-amine systems.

    PubMed

    Singh, P K; Nath, S; Bhasikuttan, A C; Kumbhakar, M; Mohanty, J; Sarkar, S K; Mukherjee, T; Pal, H

    2008-09-21

    Effect of donor amine orientation on nondiffusive ultrafast intermolecular electron transfer (ET) reactions in coumarin-amine systems has been investigated using femtosecond fluorescence upconversion measurements. Intermolecular ET from different aromatic and aliphatic amines used as donor solvents to the excited coumarin-151 (C151) acceptor occurs with ultrafast rates such that the shortest fluorescence lifetime component (tau(1)) is the measure of the fastest ET rate (tau(1)=tau(ET) (fast)=(k(ET) (fast))(-1)), assigned to the C151-amine contact pairs in which amine donors are properly oriented with respect to C151 to maximize the acceptor-donor electronic coupling (V(el)). It is interestingly observed that as the amine solvents are diluted by suitable diluents (either keeping solvent dielectric constant similar or with increasing dielectric constant), the tau(1) remains almost in the similar range as long as the amine dilution does not cross a certain critical limit, which in terms of the amine mole fraction (x(A)) is found to be approximately 0.4 for aromatic amines and approximately 0.8 for aliphatic amines. Beyond these dilutions in the two respective cases of the amine systems, the tau(1) values are seen to increase very sharply. The large difference in the critical x(A) values involving aromatic and aliphatic amine donors has been rationalized in terms of the largely different orientational restrictions for the ET reactions as imposed by the aliphatic (n-type) and aromatic (pi-type) nature of the amine donors [A. K. Satpati et al., J. Mol. Struct. 878, 84 (2008)]. Since the highest occupied molecular orbital (HOMO) of the n-type aliphatic amines is mostly centralized at the amino nitrogen, only some specific orientations of these amines with respect to the close-contact acceptor dye [also of pi-character; A. K. Satpati et al., J. Mol. Struct. 878, 84 (2008) and E. W. Castner et al., J. Phys. Chem. A 104, 2869 (2000)] can give suitable V(el) and thus

  4. Supramolecular aromaticity

    NASA Astrophysics Data System (ADS)

    Karabıyık, Hande; Sevinçek, Resul; Karabıyık, Hasan

    2014-05-01

    We report experimental and theoretical evidences for supramolecular aromaticity as a new concept to be widely used in researches about molecular crystals. CSD survey regarding frequently encountered resonance-assisted H-bonds (RAHBs) in formic acid, formamide, formimidamide, formic acid-formamide, and formamide-formimidamide dimers shows that supramolecular quasirings formed by RAHBs have remarkable electronic delocalization within themselves, which is reminiscent of aromaticity at supramolecular level. This study criticizes and reevaluates the validity of conventional judgment which states that ring systems formed by intermolecular H-bonds cannot be aromatic. Thus, the term aromaticity can be extended to supramolecular systems formed by RAHBs. Supramolecular aromaticity has a multi-fold nature involving both σ- and π-delocalization, and σ-delocalization through RAHBs takes on a task of compensating σ-deficiency within quasirings. Atomic composition in donor-acceptor set of the dimers is descriptive for supramolecular aromaticity. We revised bond-valence parameters for RAHBs and they suggest that hypervalent character of H atoms is more pronounced than their hypovalent character in RAHBs. The σ-delocalized bonding within H-bonded quasirings necessitates hypervalent character of H atoms. Quantum chemical calculations based on adiabatic Hydrogen Atom Transfer (HAT) between the monomers reveal that topological parameters at ring critical points (RCPs) of the quasirings correlate well with Shannon's entropic aromaticity index. The presence of additional LP orbital on O atoms implying more diffused LP-orbitals in donor-acceptor set leads to the formation of resonance-disabling states reducing supramolecular aromaticity of a quasiring and energetic cost of the electron transfer between the monomers. There is a nonignorable electron transfer between the monomers even in the cases where H atoms are close to donor or acceptor atom. NBO analyses have revealed that

  5. Synthesis and Structure-Activity Relationships of N-Dihydrocoptisine-8-ylidene Aromatic Amines and N-Dihydrocoptisine-8-ylidene Aliphatic Amides as Antiulcerative Colitis Agents Targeting XBP1.

    PubMed

    Xie, Meng; Zhang, Hai-Jing; Deng, An-Jun; Wu, Lian-Qiu; Zhang, Zhi-Hui; Li, Zhi-Hong; Wang, Wen-Jie; Qin, Hai-Lin

    2016-04-22

    In this study, natural quaternary coptisine was used as a lead compound to design and synthesize structurally stable and actively potent coptisine analogues. Of the synthesized library, 13 N-dihydrocoptisine-8-ylidene amines/amides were found not only to be noncytotoxic toward intestinal epithelial cells (IECs), but they were also able to activate the transcription of X-box-binding protein 1 (XBP1) targets to varying extents in vitro. Antiulcerative colitis (UC) activity levels were assessed at the in vitro molecular level as well as in vivo in animals using multiple biomarkers as indices. In an in vitro XBP1 transcriptional activity assay, four compounds demonstrated good dose-effect relationships with EC50 values of 0.0708-0.0132 μM. Moreover, two compounds were confirmed to be more potent in vivo than a positive control, demonstrating a curative effect for UC in experimental animals. Thus, the findings of this study suggest that these coptisine analogues are promising candidates for the development of anti-UC drugs. PMID:26981782

  6. Targeting polyamines and biogenic amines by green tea epigallocatechin-3-gallate.

    PubMed

    Melgarejo, Esther; Urdiales, José Luis; Sánchez-Jiménez, Francisca; Medina, Miguel Angel

    2010-02-01

    Biogenic amines and polyamines are organic polycations derived from aromatic or cationic amino acids. They exert pleiotropic effects, more related to intercellular communication in the case of biogenic amines, and to intracellular signaling in the case of polyamines. The bioactive compound epigallocatechin-3-gallate (EGCG), a major component of green tea, has been shown to target key enzyme of biogenic amine and polyamine metabolic pathways. Herein, we review the specific effects of EGCG on concrete molecular targets of both biogenic amine and polyamine metabolic pathways, and discuss the relevance of these data to support the potential therapeutic interest of this compound. PMID:19956995

  7. Method of neutralizing the corrosive surface of amine-cured epoxy resins

    NASA Technical Reports Server (NTRS)

    Lee, S. Y. (Inventor)

    1982-01-01

    The corrosive alkaline surface layer of an epoxy resin product formed by the curing of the epoxy with an aliphatic amine is eliminated by first applying a non-solvent to remove most or all of the free unreacted amine and then applying a layer of a chemical reagent to neutralize the unused amine or amine functional groups by forming a substituted urea. The surface then may be rinsed with acetone and then with alcohol. The non-solvent may be an alcohol. The neutralizing chemical reagent is a mono-isocyanate or a mono-isothiocyanate. Preferred is an aromatic mono-isocyanate such as phenyl isocyanate, nitrophenyl isocyanate and naplthyl isocyanate.

  8. Oxidative carbonylation of amines to carbamates

    SciTech Connect

    Waller, F.J.

    1987-04-01

    Within the last several years, new technologies have appeared to replace phosgene for isocyanate manufacture. These include carbamate chemistries based upon dialkyl carbonate, reductive carbonylation of nitroaromatics, and oxidative carbonylation of amines. The carbamate ester can be handled safely and is reversibly cleaved to the isocyanate. The technology described here involves the preparation of both aliphatic and aromatic carbamates from an amine, alcohol, CO, oxidant, and a non-corrosive catalyst. The catalyst precursor is Pd(OAc){sub 2} and the oxidants are copper carboxylates or copper carboxylates and molecular oxygen. The latter represents a one-step carbamate synthesis with high catalyst activity, nearly quantitative conversions and alcohol selectivities greater than 90%. Operating temperatures and pressures are 80-110{degree}C and less than 500 psi, respectively. Experiments designed to probe the mechanism will be presented along with a discussion of novel (Cu(O{sub 2}CR){sub 2}){sub 2}R'NH{sub 2} complexes.

  9. Reduction of Aromatic and Heterocyclic Aromatic N-Hydroxylamines by Human Cytochrome P450 2S1

    PubMed Central

    Wang, Kai; Guengerich, F. Peter

    2013-01-01

    Many aromatic amines and heterocyclic aromatic amines (HAAs) are known carcinogens for animals and there is also strong evidence for some in human cancer. The activation of these compounds, including some arylamine drugs, involves N-hydroxylation, usually by cytochrome P450 enzymes (P450) in Family 1 (1A2, 1A1, and 1B1). We previously demonstrated that the bioactivation product of the anti-cancer agent 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203), an N-hydroxylamine, can be reduced by P450 2S1 to its amine precursor under anaerobic conditions and, to a lesser extent, under aerobic conditions (Wang, K., and Guengerich, F. P. (2012) Chem. Res. Toxicol. 25, 1740–1751). In the present study, we tested the hypothesis that P450 2S1 is involved in the reductive biotransformation of known carcinogenic aromatic amines and HAAs. The N-hydroxylamines of 4-aminobiphenyl (4-ABP), 2-naphthylamine (2-NA), and 2-aminofluorene (2-AF) were synthesized and found to be reduced by P450 2S1 under both anaerobic and aerobic conditions. The formation of amines due to P450 2S1 reduction also occurred under aerobic conditions but was less apparent because the competitive disproportionation reactions (of the N-hydroxylamines) also yielded amines. Further, some nitroso and nitro derivatives of the arylamines could also be reduced by P450 2S1. None of the amines tested were oxidized by P450 2S1. These results suggest that P450 2S1 may be involved in the reductive detoxication of several of the activated products of carcinogenic aromatic amines and HAAs. PMID:23682735

  10. Reduction of aromatic and heterocyclic aromatic N-hydroxylamines by human cytochrome P450 2S1.

    PubMed

    Wang, Kai; Guengerich, F Peter

    2013-06-17

    Many aromatic amines and heterocyclic aromatic amines (HAAs) are known carcinogens for animals, and there is also strong evidence of some in human cancer. The activation of these compounds, including some arylamine drugs, involves N-hydroxylation, usually by cytochrome P450 enzymes (P450) in Family 1 (1A2, 1A1, and 1B1). We previously demonstrated that the bioactivation product of the anticancer agent 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203), an N-hydroxylamine, can be reduced by P450 2S1 to its amine precursor under anaerobic conditions and, to a lesser extent, under aerobic conditions [Wang, K., and Guengerich, F. P. (2012) Chem. Res. Toxicol. 25, 1740-1751]. In the study presented here, we tested the hypothesis that P450 2S1 is involved in the reductive biotransformation of known carcinogenic aromatic amines and HAAs. The N-hydroxylamines of 4-aminobiphenyl (4-ABP), 2-naphthylamine (2-NA), and 2-aminofluorene (2-AF) were synthesized and found to be reduced by P450 2S1 under both anaerobic and aerobic conditions. The formation of amines due to P450 2S1 reduction also occurred under aerobic conditions but was less apparent because the competitive disproportionation reactions (of the N-hydroxylamines) also yielded amines. Further, some nitroso and nitro derivatives of the arylamines could also be reduced by P450 2S1. None of the amines tested were oxidized by P450 2S1. These results suggest that P450 2S1 may be involved in the reductive detoxication of several of the activated products of carcinogenic aromatic amines and HAAs. PMID:23682735

  11. Oxidative aromatic coupling of meso-arylamino-porphyrins.

    PubMed

    Nowak-Król, Agnieszka; Gryko, Daniel T

    2013-11-15

    Strategic placement of the bis-arylamino group at the meso-position of porphyrins allowed fusion of these two moieties via aromatic dehydrogenation. By placing two di(naphthalene-2-yl)amine or bis(3,5-dimethoxyphenyl)amine groups at positions 5 and 15 of the porphyrin, the oxidative aromatic coupling was directed toward closing one six-membered ring. The extension of the porphyrin chromophore leads to significant change in linear optical properties, such as a bathochromic shift of absorption and broadening of the Q-band. PMID:24168727

  12. Amine salts of nitroazoles

    DOEpatents

    Kienyin Lee; Stinecipher, M.M.

    1993-10-26

    Compositions of matter, a method of providing chemical energy by burning said compositions, and methods of making said compositions are described. These compositions are amine salts of nitroazoles. 1 figure.

  13. Direct Methylation of Amines with Carbon Dioxide and Molecular Hydrogen using Supported Gold Catalysts.

    PubMed

    Du, Xian-Long; Tang, Gao; Bao, Hong-Liang; Jiang, Zheng; Zhong, Xin-Hua; Su, Dang Sheng; Wang, Jian-Qiang

    2015-10-26

    The N-methylation of amines with CO2 and H2 is an important step in the synthesis of bioactive compounds and chemical intermediates. The first heterogeneous Au catalyst is reported for this methylation reaction with good to excellent yields. The average turnover frequency (TOF) based on surface Au atoms is 45 h(-1) , which is the highest TOF value ever reported for the methylation of aniline with CO2 and H2 . Furthermore, the catalyst is tolerant toward a variety of amines, which includes aromatic, aliphatic, secondary, and primary amines. Preliminary mechanistic studies suggest that the N-alkyl formamide might be an intermediate in the N-methylation of amine process. Moreover, through a one-pot process, it is possible to convert primary amines, aldehydes, and CO2 into unsymmetrical tertiary amines with H2 as a reductant in the presence of the Au catalyst. PMID:26364582

  14. Conversion of alcohols to enantiopure amines through dual enzyme hydrogen-borrowing cascades

    PubMed Central

    Mutti, Francesco G.; Knaus, Tanja; Scrutton, Nigel S.; Breuer, Michael; Turner, Nicholas J.

    2016-01-01

    α-Chiral amines are key intermediates for the synthesis of a plethora of chemical compounds on industrial scale. Here we present a biocatalytic hydrogen-borrowing amination of primary and secondary alcohols that allows for the efficient and environmentally benign production of enantiopure amines. The method relies on the combination of an alcohol dehydrogenase (ADHs from Aromatoleum sp., Lactobacillus sp. and Bacillus sp.) enzyme operating in tandem with an amine dehydrogenase (AmDHs engineered from Bacillus sp.) to aminate a structurally diverse range of aromatic and aliphatic alcohols (up to 96% conversion and 99% enantiomeric excess). Furthermore, primary alcohols are aminated with high conversion (up to 99%). This redox self-sufficient network possesses high atom efficiency, sourcing nitrogen from ammonium and generating water as the sole by-product. PMID:26404833

  15. Formation Mechanism of NDMA from Ranitidine, Trimethylamine, and Other Tertiary Amines during Chloramination: A Computational Study

    PubMed Central

    2015-01-01

    Chloramination of drinking waters has been associated with N-nitrosodimethylamine (NDMA) formation as a disinfection byproduct. NDMA is classified as a probable carcinogen and thus its formation during chloramination has recently become the focus of considerable research interest. In this study, the formation mechanisms of NDMA from ranitidine and trimethylamine (TMA), as models of tertiary amines, during chloramination were investigated by using density functional theory (DFT). A new four-step formation pathway of NDMA was proposed involving nucleophilic substitution by chloramine, oxidation, and dehydration followed by nitrosation. The results suggested that nitrosation reaction is the rate-limiting step and determines the NDMA yield for tertiary amines. When 45 other tertiary amines were examined, the proposed mechanism was found to be more applicable to aromatic tertiary amines, and there may be still some additional factors or pathways that need to be considered for aliphatic tertiary amines. The heterolytic ONN(Me)2–R+ bond dissociation energy to release NDMA and carbocation R+ was found to be a criterion for evaluating the reactivity of aromatic tertiary amines. A structure–activity study indicates that tertiary amines with benzyl, aromatic heterocyclic ring, and diene-substituted methenyl adjacent to the DMA moiety are potentially significant NDMA precursors. The findings of this study are helpful for understanding NDMA formation mechanism and predicting NDMA yield of a precursor. PMID:24968236

  16. Aromatic graphene

    NASA Astrophysics Data System (ADS)

    Das, D. K.; Sahoo, S.

    2016-04-01

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  17. Direct Hydroxylation and Amination of Arenes via Deprotonative Cupration.

    PubMed

    Tezuka, Noriyuki; Shimojo, Kohei; Hirano, Keiichi; Komagawa, Shinsuke; Yoshida, Kengo; Wang, Chao; Miyamoto, Kazunori; Saito, Tatsuo; Takita, Ryo; Uchiyama, Masanobu

    2016-07-27

    Deprotonative directed ortho cupration of aromatic/heteroaromatic C-H bond and subsequent oxidation with t-BuOOH furnished functionalized phenols in high yields with high regio- and chemoselectivity. DFT calculations revealed that this hydroxylation reaction proceeds via a copper (I → III → I) redox mechanism. Application of this reaction to aromatic C-H amination using BnONH2 efficiently afforded the corresponding primary anilines. These reactions show broad scope and good functional group compatibility. Catalytic versions of these transformations are also demonstrated. PMID:27348154

  18. Selective photometric method for the determination of aliphatic amines in air

    SciTech Connect

    Yarym-Agaeva, N.T.; Putilina, O.N.

    1986-09-01

    This paper presents a sensitive, selective, rapid and simple method to determine aliphatic amines in air that insures an operational analysis procedure. The authors used consecutive reactions with hypochlorite and iodide in the presence of starch, proposed for the determination of ethylamine and diethylamine in the liquid phase for the study of the kinetics of the hydrolysis of N-ethylmaleamic and N,N-diethylmaleamic acid. The method is selective in the presence of aromatic amines, isocyanates and ammonia.

  19. Biodegradation of Aromatic Compounds by Escherichia coli

    PubMed Central

    Díaz, Eduardo; Ferrández, Abel; Prieto, María A.; García, José L.

    2001-01-01

    Although Escherichia coli has long been recognized as the best-understood living organism, little was known about its abilities to use aromatic compounds as sole carbon and energy sources. This review gives an extensive overview of the current knowledge of the catabolism of aromatic compounds by E. coli. After giving a general overview of the aromatic compounds that E. coli strains encounter and mineralize in the different habitats that they colonize, we provide an up-to-date status report on the genes and proteins involved in the catabolism of such compounds, namely, several aromatic acids (phenylacetic acid, 3- and 4-hydroxyphenylacetic acid, phenylpropionic acid, 3-hydroxyphenylpropionic acid, and 3-hydroxycinnamic acid) and amines (phenylethylamine, tyramine, and dopamine). Other enzymatic activities acting on aromatic compounds in E. coli are also reviewed and evaluated. The review also reflects the present impact of genomic research and how the analysis of the whole E. coli genome reveals novel aromatic catabolic functions. Moreover, evolutionary considerations derived from sequence comparisons between the aromatic catabolic clusters of E. coli and homologous clusters from an increasing number of bacteria are also discussed. The recent progress in the understanding of the fundamentals that govern the degradation of aromatic compounds in E. coli makes this bacterium a very useful model system to decipher biochemical, genetic, evolutionary, and ecological aspects of the catabolism of such compounds. In the last part of the review, we discuss strategies and concepts to metabolically engineer E. coli to suit specific needs for biodegradation and biotransformation of aromatics and we provide several examples based on selected studies. Finally, conclusions derived from this review may serve as a lead for future research and applications. PMID:11729263

  20. High capacity immobilized amine sorbents

    DOEpatents

    Gray, McMahan L.; Champagne, Kenneth J.; Soong, Yee; Filburn, Thomas

    2007-10-30

    A method is provided for making low-cost CO.sub.2 sorbents that can be used in large-scale gas-solid processes. The improved method entails treating an amine to increase the number of secondary amine groups and impregnating the amine in a porous solid support. The method increases the CO.sub.2 capture capacity and decreases the cost of utilizing an amine-enriched solid sorbent in CO.sub.2 capture systems.

  1. Functionalization of Organotrifluoroborates: Reductive Amination

    PubMed Central

    Cooper, David J.

    2010-01-01

    Herein we report the conversion of aldehyde-containing potassium and tetrabutylammonium organotrifluoroborates to the corresponding amines through reductive amination protocols. Potassium formate facilitated by catalytic palladium acetate, sodium triacetoxyborohydride, and pyridine borane have all served as effective hydride donors, reducing the initially formed imines or iminium ions to provide the corresponding amines. PMID:18412389

  2. Trace Amines and the Trace Amine-Associated Receptor 1: Pharmacology, Neurochemistry, and Clinical Implications

    PubMed Central

    Pei, Yue; Asif-Malik, Aman; Canales, Juan J.

    2016-01-01

    Biogenic amines are a collection of endogenous molecules that play pivotal roles as neurotransmitters and hormones. In addition to the “classical” biogenic amines resulting from decarboxylation of aromatic acids, including dopamine (DA), norepinephrine, epinephrine, serotonin (5-HT), and histamine, other biogenic amines, present at much lower concentrations in the central nervous system (CNS), and hence referred to as “trace” amines (TAs), are now recognized to play significant neurophysiological and behavioral functions. At the turn of the century, the discovery of the trace amine-associated receptor 1 (TAAR1), a phylogenetically conserved G protein-coupled receptor that is responsive to both TAs, such as β-phenylethylamine, octopamine, and tyramine, and structurally-related amphetamines, unveiled mechanisms of action for TAs other than interference with aminergic pathways, laying the foundations for deciphering the functional significance of TAs and its mammalian CNS receptor, TAAR1. Although, its molecular interactions and downstream targets have not been fully elucidated, TAAR1 activation triggers accumulation of intracellular cAMP, modulates PKA and PKC signaling and interferes with the β-arrestin2-dependent pathway via G protein-independent mechanisms. TAAR1 is uniquely positioned to exert direct control over DA and 5-HT neuronal firing and release, which has profound implications for understanding the pathophysiology of, and therefore designing more efficacious therapeutic interventions for, a range of neuropsychiatric disorders that involve aminergic dysregulation, including Parkinson's disease, schizophrenia, mood disorders, and addiction. Indeed, the recent development of novel pharmacological tools targeting TAAR1 has uncovered the remarkable potential of TAAR1-based medications as new generation pharmacotherapies in neuropsychiatry. This review summarizes recent developments in the study of TAs and TAAR1, their intricate neurochemistry and

  3. Trace Amines and the Trace Amine-Associated Receptor 1: Pharmacology, Neurochemistry, and Clinical Implications.

    PubMed

    Pei, Yue; Asif-Malik, Aman; Canales, Juan J

    2016-01-01

    Biogenic amines are a collection of endogenous molecules that play pivotal roles as neurotransmitters and hormones. In addition to the "classical" biogenic amines resulting from decarboxylation of aromatic acids, including dopamine (DA), norepinephrine, epinephrine, serotonin (5-HT), and histamine, other biogenic amines, present at much lower concentrations in the central nervous system (CNS), and hence referred to as "trace" amines (TAs), are now recognized to play significant neurophysiological and behavioral functions. At the turn of the century, the discovery of the trace amine-associated receptor 1 (TAAR1), a phylogenetically conserved G protein-coupled receptor that is responsive to both TAs, such as β-phenylethylamine, octopamine, and tyramine, and structurally-related amphetamines, unveiled mechanisms of action for TAs other than interference with aminergic pathways, laying the foundations for deciphering the functional significance of TAs and its mammalian CNS receptor, TAAR1. Although, its molecular interactions and downstream targets have not been fully elucidated, TAAR1 activation triggers accumulation of intracellular cAMP, modulates PKA and PKC signaling and interferes with the β-arrestin2-dependent pathway via G protein-independent mechanisms. TAAR1 is uniquely positioned to exert direct control over DA and 5-HT neuronal firing and release, which has profound implications for understanding the pathophysiology of, and therefore designing more efficacious therapeutic interventions for, a range of neuropsychiatric disorders that involve aminergic dysregulation, including Parkinson's disease, schizophrenia, mood disorders, and addiction. Indeed, the recent development of novel pharmacological tools targeting TAAR1 has uncovered the remarkable potential of TAAR1-based medications as new generation pharmacotherapies in neuropsychiatry. This review summarizes recent developments in the study of TAs and TAAR1, their intricate neurochemistry and

  4. Polycyclic amines as chloroquine resistance modulating agents in Plasmodium falciparum.

    PubMed

    Joubert, Jacques; Kapp, Erika; Taylor, Dale; Smith, Peter J; Malan, Sarel F

    2016-02-15

    Pentacycloundecylamines (PCUs) and adamantane amines, such as NGP1-01 (1) and amantadine, have shown significant channel blocking activities. They are postulated to act as chemosensitizers and circumvent the resistance of the plasmodia parasite against chloroquine (CQ) by inhibiting the p-glycoprotein efflux pump and enabling the accumulation of CQ inside the parasite digestive vacuole. Twelve polycyclic amines containing either a PCU or adamantane amine moiety conjugated to different aromatic functionalities through various tethered linkers were selected based on their channel blocking abilities and evaluated as potential chemosensitizers. Compounds 2, 4, 5 and 10 showed significant voltage-gated calcium channel (VGCC) blocking ability (IC50=0.27-35 μM) and were able to alter the CQ IC50 in differing degrees (45-81%) in the multidrug resistant Plasmodium falciparum Dd2 isolate. Among them, the PCU-dansyl amine compound (4) displayed the best potential to act as a chemosensitizer against the Dd2 strain at a 1 μM concentration (RMI=0.19) while displaying moderate antiplasmodial activity (Dd2 IC50=6.25 μM) and low in vitro cytotoxicity against a mammalian cell line (CHO, IC50=119 μM). Compounds 2 and 10 also showed some promising chemosensitizing abilities (RMI=0.36 and 0.35 respectively). A direct correlation was found between the VGCC blocking ability of these polycyclic amines and their capacity to act as CQ resistance modulating agents. PMID:26832222

  5. Interaction of protonated merocyanine dyes with amines in organic solvents

    NASA Astrophysics Data System (ADS)

    Ribeiro, Eduardo Alberton; Sidooski, Thiago; Nandi, Leandro Guarezi; Machado, Vanderlei Gageiro

    2011-10-01

    2,6-Diphenyl-4-(2,4,6-triphenylpyridinium-1-yl)phenolate ( 1a) and 4-[(1-methyl-4(1 H)-pyridinylidene)-ethylidene]-2,5-cyclohexadien-1-one ( 2a) were protonated in organic solvents (dichloromethane, acetonitrile, and DMSO) to form 1b and 2b, respectively. The appearance of the solvatochromic bands of 1a and 2a was studied UV-vis spectrophotometrically by deprotonation of 1b and 2b in solution in the presence of the following amines: aniline (AN), N-methylaniline (NMAN), N, N-dimethylaniline (NDAN), n-butylamine (BA), diethylamine (DEA), and triethylamine (TEA). Titrations of 1b and 2b with the amines were carried out and the binding constants were determined from the titration curves in each solvent, using a mathematical model adapted from the literature which considers the simultaneous participation of two dye: amine stoichiometries, 1:1 and 1:2. The data obtained showed the following base order for the two compounds in DMSO: BA > DEA > TEA, while aromatic amines did not cause any effect. In dichloromethane, the following base order for 1b was verified: TEA > DEA > BA ≫NDAN, while for 2b the order was: TEA > DEA > BA, suggesting that 1b is more acidic than 2b. The data in acetonitrile indicated for 1b and 2b the following order for the amines: DEA > TEA > BA. The diversity of the experimental data were explained based on a model that considers the level of interaction of the protonated dyes with the amines to be dependent on three aspects: (a) the basicity of the amine, which varies according to their molecular structure and the solvent in which it is dissolved, (b) the molecular structure of the dye, and (c) the solvent used to study the system.

  6. Strain Release Amination

    PubMed Central

    Gianatassio, Ryan; Lopchuk, Justin M.; Wang, Jie; Pan, Chung-Mao; Malins, Lara R.; Prieto, Liher; Brandt, Thomas A.; Collins, Michael R.; Gallego, Gary M.; Sach, Neal W.; Spangler, Jillian E.; Zhu, Huichin; Zhu, Jinjiang; Baran, Phil S.

    2015-01-01

    To optimize drug candidates, modern medicinal chemists are increasingly turning to an unconventional structural motif: small, strained ring systems. However, the difficulty of introducing substituents such as bicyclo[1.1.1]pentanes, azetidines, or cyclobutanes often outweighs the challenge of synthesizing the parent scaffold itself. Thus, there is an urgent need for general methods to rapidly and directly append such groups onto core scaffolds. Here we report a general strategy to harness the embedded potential energy of effectively spring-loaded C–C and C–N bonds with the most oft-encountered nucleophiles in pharmaceutical chemistry, amines. Strain release amination can diversify a range of substrates with a multitude of desirable bioisosteres at both the early and late-stages of a synthesis. The technique has also been applied to peptide labeling and bioconjugation. PMID:26816372

  7. Amine plant troubleshooting and optimization

    SciTech Connect

    Abry, R.G.F.; DuPart, M.S.

    1995-04-01

    A systematic method for troubleshooting and optimization of amine plants, if properly used, will result in fewer plant upsets, quick and correct responses to changing conditions and long-term profitable operations of any amine unit. It is important for amine plants to maintain safe, continuous and optimized operations for short- and long-term success. Effective and fast resolution of maine unit upsets plays a large part in this success. These considerations are as important in plants using generic amines such as monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA) and specialty amines based on MDEA. The key to troubleshooting and optimization is a systematic approach. Developing and using control charts can also be used to monitor amine plant operations. By using these techniques collectively, a formal method for troubleshooting and optimization can be established. This will ultimately result in a more trouble-free, continuous operation.

  8. Rodent repellent studies. IV. Preparation and properties of trinitrobenzene-aryl amine complexes

    USGS Publications Warehouse

    DeWitt, J.B.; Bellack, E.; Welch, J.F.

    1953-01-01

    Data are presented on methods of preparation, chemical arid physical characteristics, toxicity, and repellency to rodents of complexes of symmetrical trinitrohenzene with various aromatic amines: When applied in suitable carriers or incorporated in plastic .films, members of this series ofmaterials were shown to offer significant increases in time required by wild rodents to damage common packaging materials.

  9. Selective ruthenium-catalyzed transfer hydrogenations of nitriles to amines with 2-butanol.

    PubMed

    Werkmeister, Svenja; Bornschein, Christoph; Junge, Kathrin; Beller, Matthias

    2013-04-01

    Transfer your hydrogen: Fast and general transfer hydrogenation of nitriles to form primary amines is possible with a homogeneous Ru/1,4-bis(diphenylphosphino)butane (DPPB) catalyst (see scheme). The use of 2-butanol as the hydrogen-transfer reagent is essential for the selective reduction of aromatic, heteroaromatic, and aliphatic nitriles with this system. PMID:23450803

  10. Lignin amine microemulsions

    SciTech Connect

    DaGue, M.G.

    1992-03-10

    This patent describes a method of recovering hydrocarbons from an underground hydrocarbon formation having at least one injection well and at least one production well. It comprises injecting into the formation through an injection well a microemulsion comprising an internal phase of a primary amine having from about 8 to about 22 carbon atoms, lignin, a water soluble anionic surfactant, a solubilizer and an oil; and an external phase of brine comprising greater than about 90% by weight of the microemulsion; driving the microemulsion through the formation; and producing hydrocarbons through a production well.

  11. Solid amine development program

    NASA Technical Reports Server (NTRS)

    Lovell, J. S.

    1973-01-01

    A regenerable solid amine material to perform the functions of humidity control and CO2 removal for space shuttle type vehicle is reported. Both small scale and large scale testing have shown this material to be competitive, especially for the longer shuttle missions. However, it had been observed that the material off-gasses ammonia under certain conditions. This presents two concerns. The first, that the ammonia would contaminate the cabin atmosphere, and second, that the material is degrading with time. An extensive test program has shown HS-C to produce only trace quantities of atmospheric contaminants, and under normal extremes, to have no practical life limitation.

  12. Vanadium-catalyzed oxidative Strecker reaction: α-C–H cyanation of para-methoxyphenyl (PMP)-protected primary amines

    PubMed Central

    Zhu, Chen; Xia, Ji-Bao; Chen, Chuo

    2013-01-01

    We describe an oxidative Strecker reaction that allows for direct cyanation of para-methoxyphenyl (PMP)-protected primary amines. A vanadium(V) complex was used as the catalyst and TBHP as the oxidant. The cyanation occurs at the α-C position bearing either an alkyl or an aromatic group. This method provides a direct access to α-aminonitrile from amines with one-carbon extension. PMID:24415804

  13. Copper(I)-catalyzed amination of aryl halides in liquid ammonia.

    PubMed

    Ji, Pengju; Atherton, John H; Page, Michael I

    2012-09-01

    The amination of aryl halides in liquid ammonia (LNH(3)) is catalyzed by a copper(I) salt/ascorbate system to yield primary aromatic amines in good to excellent yields. The low concentrations of catalyst required and the ease of product isolation suggest that this process has potential industrial applications. Commonly used ligands for analogous metal-catalyzed reactions are not effective. The rate of amination of iodobenzene in liquid ammonia is first order in copper(I) catalyst concentration. The small Hammett ρ = 0.49 for the amination of 4-substituted iodobenzenes in liquid ammonia at 25 °C indicates that the C-I bond is not significantly broken in the transition state structure and that there is a small generation of negative charge in the aryl ring, which is compatible with the oxidative addition of the copper ion being rate limiting. PMID:22849292

  14. Dirhodium-catalyzed C-H arene amination using hydroxylamines.

    PubMed

    Paudyal, Mahesh P; Adebesin, Adeniyi Michael; Burt, Scott R; Ess, Daniel H; Ma, Zhiwei; Kürti, László; Falck, John R

    2016-09-01

    Primary and N-alkyl arylamine motifs are key functional groups in pharmaceuticals, agrochemicals, and functional materials, as well as in bioactive natural products. However, there is a dearth of generally applicable methods for the direct replacement of aryl hydrogens with NH2/NH(alkyl) moieties. Here, we present a mild dirhodium-catalyzed C-H amination for conversion of structurally diverse monocyclic and fused aromatics to the corresponding primary and N-alkyl arylamines using NH2/NH(alkyl)-O-(sulfonyl)hydroxylamines as aminating agents; the relatively weak RSO2O-N bond functions as an internal oxidant. The methodology is operationally simple, scalable, and fast at or below ambient temperature, furnishing arylamines in moderate-to-good yields and with good regioselectivity. It can be readily extended to the synthesis of fused N-heterocycles. PMID:27609890

  15. Control of Biogenic Amines in Food—Existing and Emerging Approaches

    PubMed Central

    Naila, Aishath; Flint, Steve; Fletcher, Graham; Bremer, Phil; Meerdink, Gerrit

    2010-01-01

    Biogenic amines have been reported in a variety of foods, such as fish, meat, cheese, vegetables, and wines. They are described as low molecular weight organic bases with aliphatic, aromatic, and heterocyclic structures. The most common biogenic amines found in foods are histamine, tyramine, cadaverine, 2-phenylethylamine, spermine, spermidine, putrescine, tryptamine, and agmatine. In addition octopamine and dopamine have been found in meat and meat products and fish. The formation of biogenic amines in food by the microbial decarboxylation of amino acids can result in consumers suffering allergic reactions, characterized by difficulty in breathing, itching, rash, vomiting, fever, and hypertension. Traditionally, biogenic amine formation in food has been prevented, primarily by limiting microbial growth through chilling and freezing. However, for many fishing based subsistence populations, such measures are not practical. Therefore, secondary control measures to prevent biogenic amine formation in foods or to reduce their levels once formed need to be considered as alternatives. Such approaches to limit microbial growth may include hydrostatic pressures, irradiation, controlled atmosphere packaging, or the use of food additives. Histamine may potentially be degraded by the use of bacterial amine oxidase or amine-negative bacteria. Only some will be cost-effective and practical for use in subsistence populations. PMID:21535566

  16. Pd/C Catalyzed Carbonylation of Azides in the Presence of Amines.

    PubMed

    Zhao, Jin; Li, Zongyang; Yan, Shuaihu; Xu, Shiyang; Wang, Ming-An; Fu, Bin; Zhang, Zhenhua

    2016-04-15

    A facile and efficient Pd/C-catalyzed carbonylation of both aliphatic and aromatic azides in the presence of amines is reported. Serving as the widely existed fragments in an array of biological pharmaceuticals, functionalized unsymmetrical ureas were straightforwardly synthesized by using readily available and cheap azides with amines under CO atmosphere, with the extrusion of N2 as the only byproduct. It was found that not only aryl azides but also benzyl and alkyl azides were suited for this methodology. Another feature of this procedure was the employment of a highly efficient palladium charcoal catalytic system. PMID:27015001

  17. CuI/Oxalic Diamide Catalyzed Coupling Reaction of (Hetero)Aryl Chlorides and Amines.

    PubMed

    Zhou, Wei; Fan, Mengyang; Yin, Junli; Jiang, Yongwen; Ma, Dawei

    2015-09-23

    A class of oxalic diamides are found to be effective ligands for promoting CuI-catalyzed aryl amination with less reactive (hetero)aryl chlorides. The reaction proceeds at 120 °C with K3PO4 as the base in DMSO to afford a wide range of (hetero)aryl amines in good to excellent yields. The bis(N-aryl) substituted oxalamides are superior ligands to N-aryl-N'-alkyl substituted or bis(N-alkyl) substituted oxalamides. Both the electronic nature and the steric property of the aromatic rings in ligands are important for their efficiency. PMID:26352639

  18. Solid Phase Synthesis of Helically Folded Aromatic Oligoamides.

    PubMed

    Dawson, S J; Hu, X; Claerhout, S; Huc, I

    2016-01-01

    Aromatic amide foldamers constitute a growing class of oligomers that adopt remarkably stable folded conformations. The folded structures possess largely predictable shapes and open the way toward the design of synthetic mimics of proteins. Important examples of aromatic amide foldamers include oligomers of 7- or 8-amino-2-quinoline carboxylic acid that have been shown to exist predominantly as well-defined helices, including when they are combined with α-amino acids to which they may impose their folding behavior. To rapidly iterate their synthesis, solid phase synthesis (SPS) protocols have been developed and optimized for overcoming synthetic difficulties inherent to these backbones such as low nucleophilicity of amine groups on electron poor aromatic rings and a strong propensity of even short sequences to fold on the solid phase during synthesis. For example, acid chloride activation and the use of microwaves are required to bring coupling at aromatic amines to completion. Here, we report detailed SPS protocols for the rapid production of: (1) oligomers of 8-amino-2-quinolinecarboxylic acid; (2) oligomers containing 7-amino-8-fluoro-2-quinolinecarboxylic acid; and (3) heteromeric oligomers of 8-amino-2-quinolinecarboxylic acid and α-amino acids. SPS brings the advantage to quickly produce sequences having varied main chain or side chain components without having to purify multiple intermediates as in solution phase synthesis. With these protocols, an octamer could easily be synthesized and purified within one to two weeks from Fmoc protected amino acid monomer precursors. PMID:27586338

  19. Amine-Amine Exchange in Aminium-Methanesulfonate Aerosols

    SciTech Connect

    Dawson, Matthew L.; Varner, Mychel E.; Perraud, Veronique M.; Ezell, Michael J.; Wilson, Jacqueline M.; Zelenyuk, Alla; Gerber, Robert B.; Finlayson-Pitts, Barbara J.

    2014-12-18

    Aerosol particles are ubiquitous in the atmosphere and have been shown to impact the Earth’s climate, reduce visibility, and adversely affect human health. Modeling the evolution of aerosol systems requires an understanding of the species and mechanisms involved in particle growth, including the complex interactions between particle- and gas-phase species. Here we report studies of displacement of amines (methylamine, dimethylamine or trimethylamine) in methanesulfonate salt particles by exposure to a different gas-phase amine, using a single particle mass spectrometer, SPLAT II. The variation of the displacement with the nature of the amine suggests that behavior is dependent on water in or on the particles. Small clusters of methanesulfonic acid with amines are used as a model in quantum chemical calculations to identify key structural elements that are expected to influence water uptake, and hence the efficiency of displacement by gas-phase molecules in the aminium salts. Such molecular-level understanding of the processes affecting the ability of gas-phase amines to displace particle-phase aminium species is important for modeling the growth of particles and their impacts in the atmosphere.

  20. Tunable Control of Polyproline Helix (PPII) Structure via Aromatic Electronic Effects: An Electronic Switch of Polyproline Helix

    PubMed Central

    2015-01-01

    Aromatic rings exhibit defined interactions via the unique aromatic π face. Aromatic amino acids interact favorably with proline residues via both the hydrophobic effect and aromatic–proline interactions, C−H/π interactions between the aromatic π face and proline ring C–H bonds. The canonical aromatic amino acids Trp, Tyr, and Phe strongly disfavor a polyproline helix (PPII) when they are present in proline-rich sequences because of the large populations of cis amide bonds induced by favorable aromatic–proline interactions (aromatic–cis-proline and proline–cis-proline–aromatic interactions). We demonstrate the ability to tune polyproline helix conformation and cis–trans isomerism in proline-rich sequences using aromatic electronic effects. Electron-rich aromatic residues strongly disfavor polyproline helix and exhibit large populations of cis amide bonds, while electron-poor aromatic residues exhibit small populations of cis amide bonds and favor polyproline helix. 4-Aminophenylalanine is a pH-dependent electronic switch of polyproline helix, with cis amide bonds favored as the electron-donating amine, but trans amide bonds and polyproline helix preferred as the electron-withdrawing ammonium. Peptides with block proline–aromatic PPXPPXPPXPP sequences exhibited electronically switchable pH-dependent structures. Electron-poor aromatic amino acids provide special capabilities to integrate aromatic residues into polyproline helices and to serve as the basis of aromatic electronic switches to change structure. PMID:25075447

  1. Amine Swingbed Payload Project Management

    NASA Technical Reports Server (NTRS)

    Walsch, Mary; Curley, Su

    2013-01-01

    The International Space Station (ISS) has been designed as a laboratory for demonstrating technologies in a microgravity environment, benefitting exploration programs by reducing the overall risk of implementing such technologies in new spacecraft. At the beginning of fiscal year 2010, the ISS program manager requested that the amine-based, pressure-swing carbon dioxide and humidity absorption technology (designed by Hamilton Sundstrand, baselined for the Orion Multi-Purpose Crew Vehicle, and tested at the Johnson Space Center in relevant environments, including with humans, since 2005) be developed into a payload for ISS Utilization. In addition to evaluating the amine technology in a flight environment before the first launch of the Orion vehicle, the ISS program wanted to determine the capability of the amine technology to remove carbon dioxide from the ISS cabin environment at the metabolic rate of the full 6 ]person crew. Because the amine technology vents the absorbed carbon dioxide and water vapor to space vacuum (open loop), additional hardware needed to be developed to minimize the amount of air and water resources lost overboard. Additionally, the payload system would be launched on two separate Space Shuttle flights, with the heart of the payload-the swingbed unit itself-launching a full year before the remainder of the payload. This paper discusses the project management and challenges of developing the amine swingbed payload in order to accomplish the technology objectives of both the open -loop Orion application as well as the closed-loop ISS application.

  2. Amine Swingbed Payload Project Management

    NASA Technical Reports Server (NTRS)

    Hayley, Elizabeth; Curley, Su; Walsh, Mary

    2011-01-01

    The International Space Station (ISS) has been designed as a laboratory for demonstrating technologies in a microgravity environment, benefitting exploration programs by reducing the overall risk of implementing such technologies in new spacecraft. At the beginning of fiscal year 2010, the ISS program manager requested that the amine-based, pressure-swing carbon dioxide and humidity absorption technology (designed by Hamilton Sundstrand, baselined for the ORION Multi-Purpose Crew Vehicle, and tested at the Johnson Space Center in relevant environments, including with humans, since 2005) be developed into a payload for ISS Utilization. In addition to evaluating the amine technology in a flight environment before the first launch of the ORION vehicle, the ISS program wanted to determine the capability of the amine technology to remove carbon dioxide from the ISS cabin environment at the metabolic rate of the full 6-person crew. Because the amine technology vents the absorbed carbon dioxide and water vapor to space vacuum (open loop), additional hardware needed to be developed to minimize the amount of air and water resources lost overboard. Additionally, the payload system would be launched on two separate Space Shuttle flights, with the heart of the payload the swingbed unit itself launching a full year before the remainder of the payload. This paper discusses the project management and challenges of developing the amine swingbed payload in order to accomplish the technology objectives of both the open-loop ORION application as well as the closed-loop ISS application.

  3. Amine Swingbed Payload Technology Demonstration

    NASA Technical Reports Server (NTRS)

    Sweterlitsch, Jeffrey

    2014-01-01

    The Amine Swingbed is an amine-based, vacuum-regenerated adsorption technology for removing carbon dioxide and humidity from a habitable spacecraft environment, and is the baseline technology for the Orion Program’s Multi-Purpose Crew Vehicle (MPCV). It uses a pair of interleaved-layer beds filled with SA9T, the amine sorbent, and a linear multiball valve rotates 270° back and forth to control the flow of air and vacuum to adsorbing and desorbing beds. One bed adsorbs CO2 and H2O from cabin air while the other bed is exposed to vacuum for regeneration by venting the CO2 and H2O. The two beds are thermally linked, so no additional heating or cooling is required. The technology can be applied to habitable environments where recycling CO2 and H2O is not required such as short duration missions.

  4. Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C-H Amination and Hydroxylation.

    PubMed

    Zheng, Yi-Wen; Chen, Bin; Ye, Pan; Feng, Ke; Wang, Wenguang; Meng, Qing-Yuan; Wu, Li-Zhu; Tung, Chen-Ho

    2016-08-17

    We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobalt catalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually mild conditions in excellent yields and selectivities. PMID:27467115

  5. The Elusive Metal-Free Primary Amination of Arylboronic Acids: Synthetic Studies and Mechanism by Density Functional Theory

    PubMed Central

    Zhu, Chen; Li, Gongqiang; Ess, Daniel H.; Falck, John R.; Kürti, László

    2012-01-01

    Herein, we disclose the first metal-free synthesis of primary aromatic amines from arylboronic acids, a reaction that has eluded synthetic chemists for decades. This remarkable transformation affords structurally diverse primary arylamines in good chemical yields, including a variety of halogenated primary anilines that often cannot be prepared via transition metal-catalyzed amination. The reaction is operationally simple, requires only a slight excess of aminating agent, proceeds under neutral or basic conditions and, importantly, it can be scaled up to provide multigram quantities of primary anilines. Density functional calculations reveal that the most likely mechanism involves a facile 1,2-aryl migration and that the presence of an ortho nitro group in the aminating agent plays a critical role in lowering the free energy barrier of the 1,2-aryl migration step. PMID:23082853

  6. Stereoselective intermolecular C-H amination reactions.

    PubMed

    Lebel, Hélène; Trudel, Carl; Spitz, Cédric

    2012-08-14

    A novel chiral N-mesyloxycarbamate to perform rhodium-catalyzed stereoselective C-H amination reactions is reported. Chiral benzylic and propargylic amines are produced in good yields and selectivities using ethyl acetate as solvent. The corresponding free amines are easily obtained by cleavage of the chiral reagent, which could also be recovered. PMID:22751570

  7. Amine catalyzed condensation of tetraethylorthosilicate

    NASA Technical Reports Server (NTRS)

    Jones, S.

    2001-01-01

    The catalysis of the condensation of hydrolyzed metal alkoxides by amines has been mentioned in the literature, but there has been no systematic study of their influence on the rate of the condensation reaction of the alkoxide and the microstructure of the resultant gel.

  8. Nucleophilic Aromatic Substitution.

    ERIC Educational Resources Information Center

    Avila, Walter B.; And Others

    1990-01-01

    Described is a microscale organic chemistry experiment which demonstrates one feasible route in preparing ortho-substituted benzoic acids and provides an example of nucleophilic aromatic substitution chemistry. Experimental procedures and instructor notes for this activity are provided. (CW)

  9. Trimerization of aromatic nitriles

    NASA Technical Reports Server (NTRS)

    Hsu, L. C. (Inventor)

    1977-01-01

    Triazine compounds and cross-linked polymer compositions were made by heating aromatic nitriles to a temperature in the range of about 100 C to about 700 C, in the presence of a catalyst or mixture of catalysts. Aromatic nitrile-modified (terminated and/or appended) imide, benzimidazole, imidazopyrrolone, quinoxaline, and other condensation type prepolymers or their precopolymers were made which were trimerized with or without a filler by the aforementioned catalytic trimerization process.

  10. Aromatic Polyimide Foam

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S. (Inventor); St.Clair, Terry L. (Inventor); Echigo, Yoshiaki (Inventor); Kaneshiro, Hisayasu (Inventor)

    2000-01-01

    A mechanically undensified aromatic polyimide foam is made from an aromatic polyimide precursor solid residuum and has the following combination of properties: a density according to ASTM D-3574A of about 0.5 pounds/cu.ft to about 20 pounds/cu.ft; a compression strength according to ASTM D-3574C of about 1.5 psi to about 1500 psi; and a limiting oxygen index according to ASTM D-2863 of about 35% oxygen to about 75% oxygen at atmospheric pressure. The aromatic polyimide foam has no appreciable solid inorganic contaminants which are residues of inorganic blowing agents. The aromatic polyimide which constitutes the aromatic polyimide foam has a glass transition temperature (Tg) by differential scanning calorimetry of about 235 C to about 400 C; and a thermal stability of 0 to about 1% weight loss at 204 C as determined by thermogravinietric analysis (TGA). The aromatic polyimide foam has utility as foam insulation and as structural foam, for example, for aeronautical, aerospace and maritime applications.