Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “NAPHTHALENES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1998

Metabolism and toxicity of diisopropylnaphthalene as compared to naphthalene and monoalkyl naphthalenes: a minireview.

Detailed knowledge does exist on the toxicological safety of diisopropylnaphthalene (DIPN). Its metabolism is the key to understanding its very low toxicity. The metabolic pathway of 2,6-DIPN in rats was found to proceed almost exclusively through oxidation of the isopropyl side-chain. This has decisive toxicological implications, which could be demonstrated by comparing the lung-specific toxic effects of naphthalenes in mouse: the lack of ring oxidation correlates well with lack of lung toxicity while, vice versa, the extent of enzymatic oxidative attack at the aromatic ring structure results in a toxic pattern that is observed with naphthalene and its monomethyl derivatives. It is concluded that DIPN and other highly alkylated naphthalenes are supposed to offer favourable safety properties because of their 'alkyl character' and therefore must not be compared with the toxic properties of naphthalene and closely related aromatic compounds.

Anemia, Hemolytic↗
PubMed2000

Naphthalene and donor cell density influence field conjugation of naphthalene catabolism plasmids.

We examined transfer of naphthalene-catabolic genes from donor microorganisms native to a contaminated site to site-derived, rifampin-resistant recipient bacteria unable to grow on naphthalene. Horizontal gene transfer (HGT) was demonstrated in filter matings using groundwater microorganisms as donors. Two distinct but similar plasmid types, closely related to pDTG1, were retrieved. In laboratory-incubated sediment matings, the addition of naphthalene stimulated HGT. However, recipient bacteria deployed in recoverable vessels in the field site (in situ) did not retrieve plasmids from native donors. Only when plasmid-containing donor cells and naphthalene were added to the in situ mating experiments did HGT occur.

Bacteria↗
PubMed1999

Naphthalene-induced cataract model in rats: A comparative study between slit and retroillumination images, biochemical changes and naphthalene dose and duration.

PURPOSE: The purpose of the study was to compare different methods of photographic evaluation of cataract formation in rats in response to different regimes of naphthalene treatment. Furthermore, we intended to study the relationship between cataract extension and biochemical parameters. METHODS: Brown Norway rats were treated with 0.10-1.5 g naphthalene/kg body weight, twice a week for ten weeks to induce cataract or placebo. Slit illumination and retroillumination (SI and RI) photographs were produced by an EAS-1000 instrument to document cataract formation as light-scattering intensity. The degree of the cataractous changes was quantified in SI photographs by the peak height and the integrated peak area, and in RI photographs by threshold setting. Finally, the lens concentration of Na(+) and K( +) and the protein composition were analyzed and correlated to the photographic analysis. RESULTS: The degree of the cataractous changes was most linearly related to dose and duration when the integrated peak area was estimated. However, protein fractions were non-linearly related to the cataractous changes estimated. Alterations in concentration of Na(+) and K(+) were small or insignificant, which indicate that naphthalene-induced cataract is not caused by osmotic changes. The lowest possible naphthalene dose to induce cataractous changes was between 0.10 and 0.50 g/kg twice a week for ten weeks. CONCLUSIONS: 0.50 and 1.0 g naphthalene/kg twice a week appeared to be optimal, because the rats in these groups were healthy and the cataractous changes were consistent between animals. Thus, the combination of the animal model with the cataract quantification system has the potential to be useful and reliable in studies of cataract-preventive compounds.

Animals↗
PubMed2002

Urinary naphthalene mercapturates as biomarkers of exposure and stereoselectivity of naphthalene epoxidation.

Previous work has shown that the rate and stereochemistry of naphthalene epoxidation correlates with differences in susceptibility to cytotoxicity. The development of methods for measuring epoxide formation in vivo could provide a marker for assessing events critical to naphthalene cytotoxicity that are applicable to humans. Here, urinary diastereomeric mercapturates have been measured in mice (susceptible) and rats (nonsusceptible) after intraperitoneal administration (1.56-200 mg/kg) or inhalation exposures (0.8-110 ppm, 4 h) to naphthalene. No significant differences were observed in the percentage of the dose eliminated as mercapturate in urine between mice (25-34%) and rats (24-35%) or at varying doses after i.p. administration. The amounts of urinary mercapturate after 4-h exposures were considerably greater in mice than rats. In mice, the ratio of diastereomeric mercapturates derived from the 1R,2S- to 1S,2R-epoxide was 1:1 at low doses (1-3 mg/kg), increased to 3:1 at intermediate doses (50 mg/kg), and decreased to 2:1 at high doses (100 and 200 mg/kg). In rats, these ratios remained less than 1:1 at all doses. After inhalation, ratios were 5 to 6:1 at low concentrations (less than 15 ppm) and decreased to 3:1 at higher concentrations (15-100 ppm) in mice, whereas in rats, the ratios were 1:1 or less for all concentrations. These studies show that mercapturates provide good assessments of internal dose, that there are not significant differences between mice and rats in the percentage eliminated as mercapturate but that the ratios of mercapturates derived from the 1R,2S- versus 1S,2R-epoxide differ markedly and are consistent with previous in vitro metabolism studies.

Acetylcysteine↗
PubMed2006

Phenanthrene degradation in Arthrobacter sp. P1-1: initial 1,2-, 3,4- and 9,10-dioxygenation, and meta- and ortho-cleavages of naphthalene-1,2-diol after its formation from naphthalene-1,2-dicarboxylic acid and hydroxyl naphthoic acids.

Arthrobacter sp. P1-1, isolated from a polycyclic aromatic hydrocarbon (PAH)-contaminated site in Hilo, HI, USA, can decompose phenanthrene (40 mg l(-1)) completely within 7 days. A detailed phenanthrene metabolism map was constructed based on metabolite analysis and replacement cultures. Initial dioxygenation occurs on 1,2-, 3,4-, and 9,10-C of phenanthrene, dominantly on 3,4-C positions. Rapid accumulation of 5,6- and 7,8-benzocoumarin suggests that phenanthrene-1,2- and -3,4-diols mainly undergo meta-cleavage. However, a trace amount of o-carboxyvinylnaphthoates and diphenic acid indicates a limited extent of ortho-cleavage of the diols. Naphthalene-1,2-diol, as a common and converged metabolite, was formed from 1-[(E)-2-carboxyvinyl]-2-naphthoic acid, naphthalene-1,2-dicarboxylic acid, and 1-hydroxy-2-naphthoic acid in separate culture tests. Naphthalene-1,2-diol is then degraded in a dominant phthalic acid pathway and a minor salicylic acid pathway. Several metabolites of phthalic acid were found, while no salicylic acid metabolites were detected. The strain P1-1 likely has a very diverse set of PAH-degrading enzymes or the enzymes having relaxed substrate-specificity.

Arthrobacter↗
PubMed1980

New cyclopenta[a]naphthalene derivatives. Synthesis of 2-(carbamylmethyl)-8-hydroxy-3H-cyclopental[a]naphthalene as a possible deoxyribonucleic acid binding agent.

8-Methoxy-1-oxo-2,3-dihydro-1H-cyclopenta]a]naphthalene (4) was converted to the oxalyl derivative (7) by treatment with diethyl oxalate in the presence of sodium ethoxide. Compound 7 in the form of the sodium salt was alkylated with ethyl bromoacetate in DMF to 2-(carbethoxymethyl)-8-methoxy-1-oxo-2,3-dihydro-1H-cyclopenta[a]naphthalene (8). Treatment of 8 with methanolic ammonia yielded the corresponding amide (9). Dealkylation of 8 with 48% HBr and subsequent esterification gave compound 10. Ammonolysis of 10 led to the amide 11, which after reduction and subsequent dehydration of the reduced product afforded the desired compound, 2-(carbamylmethyl)-8-hydroxy-3H-cyclopenta[a]naphthalene (2). Compound 2 was found to be mildly growth inhibitory to L1210 and CCRF--CEM leukemic cells in culture. From thermal transition temperature studies, compound 2 was found to bind to calf thymus DNA and the poly(deoxyribonucleotides), e.g., poly(dG).poly(dC), poly(dG-dC), poly(dA).poly(dT), and poly(dA-dT).

Animals↗
PubMed1994

Infrared spectroscopy of polycyclic aromatic hydrocarbon cations. 1. Matrix-isolated naphthalene and perdeuterated naphthalene.

Ionized polycyclic aromatic hydrocarbons (PAHs) are thought to constitute an important component of the interstellar medium. Despite this fact, the infrared spectroscopic properties of ionized PAHs are almost unknown. The results we present here derive from our ongoing spectroscopic study of matrix isolated PAH ions and include the spectra of the naphthalene cation, C10H8+, and its fully deuterated analog, C10D8+, between 4000 and 200 cm-1. Ions are generated in situ Lyman-alpha photoionization of the neutral precursor. Bands of the C10H8+ ion are observed at 1525.7, 1518.8, 1400.9, 1218.0, 1216.9, 1214.9, 1023.2, and 758.7 cm-1. Positions and relative intensities of these bands agree well with those in the available literature. The 758.7 cm-1 band has not previously been reported. C10D8+ ion bands appear at 1466.2, 1463.8, 1379.4, 1373.8, 1077.3, 1075.4, and 1063.1 cm-1. Compared to the analogous modes in the neutral molecule, the intensities of the cation's CC modes are enhanced by an order of magnitude, while CH modes are depressed by this same factor. Integrated absorption intensities are calculated for the strongest bands of C10H8 and for the observed bands of C10H8+. Absolute intensities derived for the naphthalene cation differ from earlier experimental results by a factor of approximately 50, and from theoretical predictions by a factor of approximately 300. Reasons for these discrepancies and from the astronomical implications of PAH cation spectra are discussed.

Astronomy↗
PubMed2002

Ozonation of 1-naphthalene, 1,5-naphthalene, and 3-nitrobenzene sulphonic acids in aqueous solutions.

Ozone oxidation kinetics of 1-naphthalene (INS), 1,5-naphthalene (1,5NDS), and 3-nitrobenzene (3NBS) sulphonic acid is reported here. The contribution of indirect free-radical pathways and direct ozone reactions are accounted for in the proposed model. Second order kinetic constants of direct reactions were estimated at around 252 (M(-1)s(-1)), 41 (M(-1)s(-1)) and 22 (M(-1)s(-1)), for INS, 1,5NDS, and 3NBS sulphonic adds, respectively. At pH 3, the indirect reaction accounted for 2%, 15% and 4% of total primary oxidation of 1NS, 1,5NBS, and 3NBS sulphonic acids, respectively. At pH 9, indirect reaction contribution increased to 73%, 84% and 48%, respectively. C4 compounds (maleic and fumaric acids), C2 (oxalic), C1 (formic) and sulphate were identified as oxidation by-products in all cases. TOC slowly decreased throughout ozonation, reaching around 40-60% and 60-70% reduction over 90 min, at pH 7 and 3, respectively.

Kinetics↗
PubMed2004

Polaromonas naphthalenivorans sp. nov., a naphthalene-degrading bacterium from naphthalene-contaminated sediment.

Strain CJ2T, capable of growth on naphthalene as a sole carbon and energy source, was isolated from coal-tar-contaminated freshwater sediment. The Gram reaction of strain CJ2T was negative. The cells were non-spore-forming, non-motile cocci (without flagella). The isolate was found to be an aerobic heterotroph capable of utilizing glucose and other simple sugars. Growth was observed between 4 and 25 degrees C (optimum, 20 degrees C) and between pH 6.0 and 9.0 (optimum, pH 7.0-7.5). The G+C content of the genomic DNA was 61.5 mol% and the major quinone was ubiquinone-8. The peptidoglycan of strain CJ2T was determined as belonging to type A1-gamma, meso-diaminopimelic acid. The major fatty acids of strain CJ2T were 16:1omega7c (67.0%), 16:0 (19.6%), 18:1omega7c (approximately 7.9%) and 10:0 3-OH (approximately 2.5%). The polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Mycolic acid and glycolipids could not be detected. Comparative 16S rDNA analysis indicated that strain CJ2T is related to the family Comamonadaceae and that the nearest phylogenetic relative was Polaromonas vacuolata 34-PT (97.1% similarity). On the basis of the physiological and molecular properties, the naphthalene-degrading isolate was designated Polaromonas naphthalenivorans sp. nov. The type strain is CJ2T (=ATCC BAA-779T=DSM 15660T).

Biodegradation, Environmental↗
PubMed2005

In situ naphthalene bioactivation and nasal airflow cause region-specific injury patterns in the nasal mucosa of rats exposed to naphthalene by inhalation.

Despite the fact that naphthalene (NA), a volatile, ubiquitous air pollutant, was recently identified as a probable human carcinogen, little is known about nasal cytotoxicity from inhaled NA. To define and compare acute nasal injury from inhalation and systemic NA exposures, male Sprague-Dawley rats were exposed to filtered air; 3.4 or 23.8 ppm NA by inhalation for 4 h; or to 0, 25, 50, 100, or 200 mg/kg NA via intraperitoneal injection. Severe cellular injury occurred exclusively in the olfactory mucosa 24 h postinhalation exposure to 3.4 ppm NA for 4 h. This level is significantly below both the current Occupational Safety and Health Administration standard (10 ppm; 8 h) for NA and the lowest observed adverse effect level (10 ppm; 2 years) for the incidence of rat olfactory neoplasms. Injury within the olfactory mucosa from inhaled NA was confined to the medial meatus, whereas systemic NA generated severe injury throughout the olfactory region. The pattern of nasal injury from inhaled NA in this study is consistent with previous studies of nasal airflow simulation within the olfactory region. The nonolfactory mucosa on the nasal septum, a high airflow region, metabolized naphthalene slowly, whereas the olfactory regions of the nasal septum and ethmoturbinates metabolized this substrate at high rates. This study concludes that 1) the incidence of acute nasal injury from systemic and inhaled NA correlates with the rates of regional microsomal NA metabolism and that 2) the nasal airflow pattern determines the pattern of olfactory mucosal injury from inhaled NA.

Animals↗
PubMed2001

Kinetics of ozone reactions with 1-naphthalene, 1,5-naphthalene and 3-nitrobenzene sulphonic acids in aqueous solutions.

This paper describes the ozone oxidation kinetics of 1-naphthalene (1 NS), 1,5-naphthalene (1,5NDS), and 3-nitrobenzene (3NBS) sulphonic acid. The presence of hydroxyl radicals and their effect on the overall rate of reaction was studied. Second order kinetic constants of direct reactions were estimated at around 252 M(-1) s(-1), 41 M(-1) s(-1) and 22 M(-1) s(-1), for 1NS, 1,5NDS, and 3NBS sulphonic acids, respectively. At pH 3, the indirect reaction accounted for 2%, 15% and 4% of total primary oxidation of 1 NS, 1,5NBS, and 3NBS sulphonic acids, respectively. At pH 9, indirect reaction contribution increased to 73%, 84% and 48%, respectively. C4 compounds (maleic and fumaric acids), C2 (oxalic), C1 (formic) and sulphate were identified as oxidation by-products in all cases. TOC slowly decreased throughout ozonation, reaching around 40-60% and 60-70% reduction over 90 minutes at pH 7 and 3, respectively.

Benzenesulfonates↗
PubMed2002

On the mechanism of arene-catalyzed lithiation: the role of arene dianions--naphthalene radical anion versus naphthalene dianion.

The use of lithium and a catalytic amount of an arene is a well-established methodology for the preparation of organolithium reagents that manifest greater reactivity than the classical lithium-arene solutions. In order to rationalize this conduct, the participation of a highly reduced species, the dianion, is proposed and its reactivity explored. Studies of kinetics and of distribution of products reveal that the electron-transfer (ET) reactivity profile of dilithium naphthalenide in its reaction with organic chlorides excludes alternative mechanisms of halogen-lithium exchange. The process generates organolithium compounds. The dianion thus emerges along with the radical anion as a suitable candidate for catalytic cycles in certain processes. Endowed with a higher redox potential than its radical anion counterpart, dilithium naphthalene displays a broader spectrum of reactivity and so increases the range of substrates suitable for lithiation. The reaction of dilithium naphthalene with THF is one example of the divergent reactivity of the radical anion and the dianion, which has been the source of apparent misinterpretation of results in the past and has now been appropriately addressed.

Journal Article↗
PubMed2002

Carbon networks based on 1,5-naphthalene units. Synthesis of 1,5-naphthalene nanostructures with extended pi-conjugation.

The synthesis and spectroscopic characterization of nanometer-sized conjugated molecules of 5-X-naphthylethynyl (X= NO(2), NMe(2)) units with precise length and constitution have been carried out. A new extended pi-conjugated 5-nitronaphthyl family was synthesized by palladium-catalyzed cross-coupling reaction between the protected 5-iodonaphthylethynyl 5a and 1-ethynyl-5-nitronaphthalene 9, or the resulting ethynyl compound 11 and the 1-iodo-5-nitronaphthalene 3. Catalytic oxidative dimerization of the terminal acetylene compounds permits the isolation of the corresponding 1,3-butadiyne derivatives 16-18, with the nitro groups at the ends of the conjugation, in excellent yields. A new family of conjugated 5-nitro-(naphthylethynyl)-[5-(N,N-dimethylamino)]naphthalene (20-22), was also synthesized by palladium-catalyzed cross-coupling reaction between 5-iodo-N,N-dimethylnaphthalene-1-amine (19) with the appropriate terminal acetylene (9, 11, and13 respectively). Compounds 20-22 show a fluorescence emission and also exhibit a charge-transfer absorption in the visible spectrum. X-ray structure of 20 confirms a centrosymmetric dimer association with an interplanar distance of 3.43 A, and the naphthalene rings adopt an anti conformation around the Ctbd1;C triple bond.

Journal Article↗
PubMed1988

Degradation of naphthalene-2,6- and naphthalene-1,6-disulfonic acid by a Moraxella sp.

A naphthalene-2,6-disulfonic acid (2,6NDS)-degrading Moraxella strain was isolated from an industrial sewage plant. This culture could also be adapted to naphthalene-1,6-disulfonic acid as growth substrate. Regioselective 1,2-dioxygenation effected desulfonation and catabolism to 5-sulfosalicylic acid (5SS), which also could be used as the sole carbon source. 5SS-grown cells exhibited high gentisate 1,2-dioxygenase activity. Neither 5SS- nor gentisate-grown cells oxidized 2,6NDS; therefore, 2,6NDS or an early metabolite must serve as an inducer of the initial catabolic enzyme(s).

Benzenesulfonates↗
PubMedDate not supplied

Differential pulse polarographic determination of lead in complex materials after adsorption of its N-methylethylxanthocarbamate complex on microcrystalline naphthalene or on N-methylethylxanthocarbamate-benzyldimethyltetradecylammonium-naphthalene adsorbent.

Lead is quantitatively adsorbed as the lead N-methylethylxanthocarbamate (MEXC)-benzyldimethyltetradecylammonium (BDTA) ion pair complex on microcrystalline naphthalene in the pH range 4.0-11.0. The metal is desorbed with HCI and determined by differential pulse polarography. Alternatively lead can be quantitatively adsorbed on the adsorbent (MEXC-BDTA-naphthalene) packed in a column at a flow rate of 1-2 mL/min and determined similarly. Dissolved oxygen is removed by adding a few milliliters of 4% NaBH4 solution. The detection limit is 0.12 microg/mL at the minimum instrumental settings (signal-to-noise ratio, 2). Linearity was obtained over the concentration range 0.3-20.0 microg/mL with a correlation factor of 0.9998 and a relative standard deviation of +/- 0.98%. Various parameters, such as the effect of pH, volume of aqueous phase, flow rate, and the interference of a large number of metal ions and anions, were studied in detail to optimize the conditions for the trace determination of lead in various standard alloys, standard biological materials, and environmental samples.

Adsorption↗
PubMed2006

Naphthalene amidine imide dyes by transamination of naphthalene bisimides.

Derivatives of naphthalene-1,4,5,8-tetracarboxylic acid with amidine structures have been prepared. The light absorption of the bisimide derivatives in the UV region is shifted to the visible for the amidine imides, which also fluoresce with a large Stokes shift. It has been shown how the bisimide-lactam rearrangement can be extended to amidine structures.

Journal Article↗