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 847 records · Page 47Linked to original sources
PubMed2004

Seasonal and spatial variation of polychlorinated naphthalenes and non-/mono-ortho-substituted polychlorinated biphenyls in arctic air.

Archived extracts of weekly air samples collected at remote arctic monitoring stations at Alert and Tagish, Canada, and Dunai Island, Russia, in 1994-1995 were combined into 4-week composites and analyzed for levels and seasonal trends of polychlorinated naphthalenes (PCNs) and non- and mono-ortho-substituted polychlorinated biphenyls (PCBs). Mean annual sigmaPCN concentrations were 0.69, 0.82, and 0.38 pg/m3 at Alert, Dunai, and Tagish, respectively. PCNs exhibited a seasonal trend at Alert and Dunai, with higher levels occurring during winter when air masses originating over Eurasia influence the high arctic and coincide with the haze period. Episodic, trans-Pacific transport impacted PCN concentrations at Tagish. A seasonal trend was not evident for the non-/mono-o-PCBs. The contrary PCN and non-/mono-o-PCB trends indicate that the sources of these two compound classes to arctic air differ, and that atmospheric transport from source regions has a greater influence on PCN levels than for non-/ mono-o-PCBs. PCNs apparently originating from combustion sources contribute to levels in winter, as indicated by the presence of combustion marker congeners, but evaporative emissions from source regions are likely the dominant source. PCNs contributed 71 and 75% of dioxin toxic equivalents (TEQ) relative to the non-/mono-o-PCBs at Alert and Dunai and 30% at Tagish during the winter months, demonstrating the toxicological importance of PCNs as a compound class relative to PCBs.

Air Pollutants↗
PubMed2005

An isotope exchange technique to assess mechanisms of sorption hysteresis applied to naphthalene in kerogenous organic matter.

The sorption of organic compounds to natural sorbents is often found to show hysteresis. The objective of this study was to develop an experimental technique based on the use of 14C isotopes to distinguish hysteresis due to experimental artifacts from true hysteresis due to thermodynamically irreversible processes. The study was also designed to investigate causation of true hysteresis (irreversible sorption). The technique determines the rates and the degree of isotope exchange (IE) on equilibrated sorption and desorption points at different constant bulk chemical concentrations. The technique was applied to the sorption of naphthalene (NAPH) on Beulah-Zap lignite, a low rank reference coal composed mainly of kerogen. Sorption of bulk was found to be reversible below 10(-5) g L(-1), but irreversible above 10(-4) g L(-1). Complete isotope exchange on sorption and desorption points that defined an irreversible cycle demonstrated that hysteresis was true. A comparison of normalized uptake and release kinetics of labeled and bulk NAPH at different concentrations revealed slow structural deformation processes of the sorbent during bulk sorption and desorption. This is taken as corroborating evidence for the pore deformation hypothesis of hysteresis in which incoming sorbate molecules induce quasi-reversible changes in the organic matter that lead to different pathways for sorption and desorption. Although unable to rule it out completely, the data demonstrate that physical entrapment of sorbate molecules plays a minor, if any, role to the observed hysteresis in this system.

Adsorption↗
PubMed2006

Formation and control of toxic polychlorinated compounds during incineration of wastes containing polychlorinated naphthalenes.

To estimate the potential impact on municipal solid waste (MSW) incinerator toxic equivalent (TEQ) emissions of treating wastes containing polychlorinated naphthalenes (PCNs), pilot-scale thermal treatment experiments were conducted. MSW (run 1) and MSW fortified with synthetic rubber belts containing PCNs (runs 2 and 3) were incinerated. Flue-gas and ash samples were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), coplanar polychlorinated biphenyls (co-PCBs), and PCNs. Final exhaust-gas WHO-TEQ emissions were all less than 0.1 ng/Nm3. Flue-gas TEQs were mainly from PCDFs (58-74%). When 2,3,7,8-tetrachlorodibenzo-p-dioxin relative potency factors (REPs) of specific PCN congeners from previous reports were used as estimated toxic equivalency factors to compute estimated PCN TEQs and total TEQs along with PCDDs, PCDFs, and co-PCBs, the contributions of PCNs to the total TEQs were small in ash samples and up to 28% in final exhaust gas. The TEQs in primary combustion flue gases increased through the formation of dioxins and PCNs and then decreased via secondary combustion, fabric filtration, and activated carbon adsorption. From this pilot-scale study, the incremental impact of incinerating PCN-containing wastes on annual TEQ emissions in Japan is estimated as 0.27 g of total TEQ.

Hydrocarbons, Chlorinated↗
PubMed2006

Polychlorinated naphthalenes in Great lakes air: assessing spatial trends and combustion inputs using PUF disk passive air samplers.

Passive air samplers made from polyurethane foam (PUF) disks housed in stainless steel chambers were deployed over four seasons during 2002-2003, at 15 sites in the Laurentian Great lakes, to assess spatial and temporal trends of polychlorinated naphthalenes (PCNs). Sampling rates, determined using depuration compounds pre-spiked into the PUF disk prior to exposure, were, on average, 2.9 +/- 1.1 m3 d(-1), consistent with previous studies employing these samplers. PCN air concentrations exhibited strong urban-rural differences-typically a few pg m(-3) at rural sites and an order of magnitude higher at urban sites (Toronto, 12-31 pg m(-3) and Chicago,13-52 pg m(-3)). The high concentrations at urban sites were attributed to continued emissions of historically used technical PCN. Contributions from combustion-derived PCNs seemed to be more important at rural locations where congeners 24 and 50, associated with wood and coal burning, were elevated. Congener 66/67, associated with incineration and other industrial thermal processes, was elevated at two sites and explained by nearby and/or upwind sources. Probability density maps were constructed for each site and for every integration period were shown to be a useful complement to seasonally integrated passive sampling data to resolve source-receptor relationship for PCNs and other pollutants.

Air Pollutants↗
PubMed2006

Competitive sorption of pyrene, phenanthrene, and naphthalene on multiwalled carbon nanotubes.

Knowledge of toxic chemical sorption by carbon nanotubes (CNTs) is critical for environmental application of CNTs as superior sorbents and for environmental risk assessment of both CNTs and toxic chemicals. Single-solute sorption results were reported in the literature, however, they cannot be used for predicting pollutant sorption by CNTs in wastewater and natural water systems where multiple organic contaminants are present. In this study, competitive sorption of pyrene, phenanthrene, and naphthalene on a multiwalled CNT material was investigated. All isotherms in single-, bi-, and tri-solute systems were fitted well by the Dubinin-Ashtakhov (DA) model. The isotherm of a given primary solute changed from being significantly nonlinear to nearly linear when competitors were added. The observed competitive sorption depended on the relative equilibrium concentrations of both primary and cosolutes. Significant competition was observed at relatively low concentrations of primary solute and high concentrations of competitors, while competition was much weaker in the case of relatively high concentrations of primary solute and low competitor concentrations. When the relative concentration of primary solute (Ce/Cs) approached 1, competition by other solutes seemed to disappear. Sorption and competition of three polycyclic aromatic hydrocarbons (PAHs) on CNTs could not be explained with either pore-filling or partition-adsorption mechanisms. A Polanyi-based surface adsorption mechanism was proposed to interpret the observed sorption and competition.

Carbon Radioisotopes↗
PubMed2002

Changing DNA grooves--a 1,4,5,8-naphthalene tetracarboxylic diimide bis-intercalator with the linker (beta-Ala)(3)-Lys in the minor groove.

We have been investigating a modular, threading DNA polyintercalator design based upon the 1,4,5,8-naphthalene tetracarboxylic diimide (NDI) intercalating unit. Previously, we have reported the NMR analysis of a bis-intercalator-DNA complex in which the peptide linker between NDI units was found to occupy the DNA major groove (Guelev, Lee, Sorey, Hoffman, Iverson, Chem. Biol. 2001, 8, 415-425). Here we describe the NMR analysis of a complex between a related bis-intercalator known to display altered DNA sequence specificity. In this case, the linker resides in the DNA minor groove. We have thus shown that within this set of sequence specific bis-intercalators, both DNA grooves can be accessed, setting the stage for longer threading polyintercalators designed to have linkers occupying both grooves in an alternating fashion.

DNA↗
PubMed2002

Isolation and characterization of stelladerol, a new antioxidant naphthalene glycoside, and other antioxidant glycosides from edible daylily (hemerocallis) flowers.

Daylily (Hemerocallis spp.) flowers are utilized as an important ingredient in traditional Asian cuisine and are also valued for their reputed medicinal effects. In studies of the bioactive methanol and aqueous methanol extracts of lyophilized Hemerocallis cv. Stella de Oro flowers, kaempferol, quercetin, and isorhamnetin 3-O-glycosides (1-9), phenethyl beta-D-glucopyranoside (10), orcinol beta-D-glucopyranoside (11), phloretin 2'-O-beta-D-glucopyranoside (12), phloretin 2'-O-beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyranoside (13), a new naphthalene glycoside, stelladerol (14), and an amino acid (longitubanine A) (15) have been isolated. All of these compounds were tested for their antioxidant and cyclooxygenase inhibitory activities. Stelladerol was found to possess strong antioxidant properties, inhibiting lipid oxidation by 94.6% +/- 1.4 at 10 microM in an in vitro assay. Several of the flavonol 3-O-glycoside isolates also demonstrated modest antioxidant activities at 10 microM. None of the isolates inhibited cyclooxygenase activity at 100 microM.

Antioxidants↗
PubMed2000

Spectrophotometric determination of ferbam [iron(III) dimethyl dithiocarbamate] in commercial sample and wheat grains after extraction of its bathophenanthroline tetraphenylborate complex into molten naphthalene.

A procedure has been developed for the determination of iron(III) dimethyldithiocarbamate by converting it into a iron(III)-bathophenanthroline-tetraphenylborate complex, which was then extracted into molten naphthalene, and the absorbance was measured at 534 nm against a reagent blank. Beer's law is obeyed over the concentration range 0.4-20 microg mL(-)(1) in final solution. The method is sensitive and highly selective and is applied for the determination of ferbam in a commercial sample, in mixtures with various dithiocarbamates (ziram, zineb, maneb, etc.), and from wheat grains.

Dimethyldithiocarbamate↗
PubMed1995

Pyridyl-substituted tetrahydrocyclopropa[a]naphthalenes: highly active and selective inhibitors of P450 arom.

The synthesis and biological evaluation of substituted exo-1-(4-pyridyl)-1a,2,3,7b-tetrahydro-1H-cyclopropa[a]naphthalene s as inhibitors of estrogen biosynthesis is described [H (1); 4-OCH3 (2); 5-OCH3 (3); 6-OCH3 (4); 1-CH3, 6-OCH3 (5); 4-OCH3, 7-Br (6); 6-OCH3, 5-Br (7); 4-OH (8); 5-OH (9); 6-OH (10)]. The synthetic key step--the formation of the cyclopropyl ring--was accomplished using the conditions of a modified Wolff-Kishner reduction (N2H5OH/KOH; delta T) and yielded exclusively the exo-configurated diastereomers. The racemic compounds 1-10 showed an inhibition of human placental aromatase (P450 arom) exhibiting relative potencies (rp) from 3.7 to 303 (compounds 8 and 4, respectively; rp of aminoglutethimide (AG) identical to 1, fadrozole = 359). The enantiomers of 4 and 7 were separated by LPLC on tribenzoyl cellulose and by crystallization of the diastereomeric tartrates (4). (1aS,2S,7bS)-(+)-4 (absolute configuration determined by X-ray crystallographic analysis) is the active P450 arom inhibiting enantiomer of 4 and shows a rp value of 617. Compound 4 is a reversible inhibitor showing a competitive type of inhibition and a type II difference spectrum. In vitro 4 influenced other steroidogenic P450 enzymes either not at all (bovine adrenal P450 scc) or only marginally (rat testicular P450 17, bovine adrenal P450 18). In ACTH-stimulated rat adrenal tissue, 4 was less active, inhibiting corticosterone and aldosterone formation compared to AG and fadrozole, respectively. In vivo 4 was not superior to AG as far as the inhibition of the uterotrophic activity of androstenedione (juvenile SD rats) and the reduction of the plasma estradiol concentration (pregnant mares' serum gonadotropin-primed SD rats) are concerned. Compound 4 shows marked antitumor activity in the dimethylbenzanthracene-induced mammary carcinoma of the SD rat: in the postmenopausal model it is at least as active as AG; in the premenopausal experiment it is clearly superior to AG. No induction of hepatic P450 enzymes was observed in the latter experiment. The rp value of 4 toward rat ovarian P450 arom, i.e., 23 (rp of AG identical to 1), is markedly decreased compared to the human enzyme (rp value of 303). From this fact it must be concluded that 4 should be more active in the human than in the rat.

Adrenal Glands↗
PubMed1994

Naphthalenic lignan lactones as selective, nonredox 5-lipoxygenase inhibitors. Synthesis and biological activity of (methoxyalkyl)thiazole and methoxytetrahydropyran hybrids.

Combinations of structural elements found in (methoxyalkyl)thiazole 1a and methoxytetrahydropyran 2a with a naphthalenic lignan lactone produce the potent 5-lipoxygenase (5-LO) inhibitors 3 and 4. While the nature of link Y-Z has a major effect on the in vitro activity of compounds 1 and 2, inhibitors 3 and 4 retain their potencies with either an oxymethylene (Y = O, Z = CH2) or a methyleneoxy (Y = CH2, Z = O) link. Compound 4b inhibits the oxidation of arachidonic acid to 5-hydroperoxyeicosatetraenoic acid by 5-LO (IC50 = 14 nM) and the formation of leukotriene B4 in human polymorphonuclear leukocytes (IC50 = 1.5 nM) as well as in human whole blood (IC50 = 50 nM). Compound 4b is a selective 5-LO inhibitor showing no significant inhibition of human 15-lipoxygenase or porcine 12-lipoxygenase or binding to human 5-lipoxygenase-activating protein up to 10 microM and inhibits leukotriene biosynthesis by a direct, nonredox interaction with 5-LO. Compound 15, the open form of lactone 4b, is well absorbed in the rat and is transformed into the active species 4b. In addition, 15 is orally active in the rat pleurisy model (ED50 = 0.6 mg/kg) and in the functional model of antigen-induced bronchoconstriction in allergic squirrel monkeys (95% inhibition at 0.3 mg/kg).

Animals↗
PubMed1991

Nonpeptidic angiotensin II antagonists: synthesis and in vitro activity of a series of novel naphthalene and tetrahydronaphthalene derivatives.

Starting from the structure of the novel nonpeptidic angiotensin II antagonist DuP 753, a series of more rigid analogues was prepared by replacing the biphenyl part of DuP 753 with a naphthalene ring. Five different regioisomers (compounds 6a-e) were synthesized, and receptor binding in rat smooth muscle cell preparations as well as inhibition of angiotensin II induced contraction of rabbit aortic rings was measured and the order of potency was compared with predictions made on the basis of a molecular modeling study. In good agreement with the predictions, the 2,6-substituted regioisomer 6d and its analogue 7 (isomeric at the imidazole substituent) were found to be most potent, but were still weaker than DuP 753. Tetrahydronaphthalene derivatives with and without an additional methyl group in the alpha-position to the acidic function and with this same 2,6-substitution pattern (compounds listed in Table III) were then prepared with the expectation of getting a further increase in potency. Whereas the carboxylic acid derivatives 13a,b showed activity in the expected potency range, surprisingly no further potency increase was observed after replacement of the carboxylic acid function by a tetrazole (compounds 18a,b). These results may indicate that the compounds do not bind to the AT1 receptor in the same way as DuP 753.

Angiotensin II↗
PubMed1988

Topical nonsteroidal antipsoriatic agents. 2. 2,3-(Alkylidenedioxy)naphthalene analogues of lonapalene.

A series of 2,3-(alkylidenedioxy)naphthalene (5a-p) analogues of lonapalene (RS-43179, 1), a 5-lipoxygenase inhibitor currently under clinical investigation for the treatment of psoriasis, has been prepared and evaluated for topical inhibitory activity against arachidonic acid induced mouse ear edema. The results of these studies demonstrate that introduction of the fused 2,3-alkylidenedioxy ring, in place of the acyclic 2,3-dialkoxy substituent pattern characteristic of the previous series, caused a modest dimunition in overall potency within the series. These results suggest a potential steric intolerance for these extended planar analogues, in comparison with their 2,3-dialkoxy predecessors.

Animals↗
PubMed1986

Topical nonsteroidal antipsoriatic agents. 1. 1,2,3,4-Tetraoxygenated naphthalene derivatives.

On the basis of previous observations that both 2,3-dihydro-2,2,3,3-tetrahydroxy-1,4-naphthoquinone (oxoline, 1) and 6-chloroisonaphthazarin (2) had demonstrated antipsoriatic activity in vivo, a series of structural derivatives of 2 were prepared and examined in the Scholtz-Dumas topical psoriasis bioassay. Of these six (5, 6, 9a, 10, 11a, 11b), the most effective compound was found to be 6-chloro-1,4-diacetoxy-2,3-dimethoxynaphthalene (RS-43179, lonapalene, 11a). An extensive series of 1,2,3,4-tetraoxygenated naphthalenes (16-74) incorporating variations of the ester, ether, and aryl substituents were prepared as analogues of 11a to examine the structural requirements for activity and were screened in vivo as inhibitors of arachidonic acid induced mouse ear edema, a topical bioassay capable of detecting 5-lipoxygenase inhibitors. Net lipophilicity, hydrolytic stability, and ring substitution play significant roles in determining the observed in vivo activity. Lonapalene (11a) is currently in clinical development as a topically applied nonsteroidal antipsoriatic agent.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1986

Selective thromboxane synthetase inhibitors. 4. 2-(1H-imidazol-1-ylmethyl) carboxylic acids of benzo[b]furan, benzo[b]thiophene, indole, and naphthalene.

The preparation of a series of 2-(1H-imidazol-1-ylmethyl)-substituted carboxylic acids of benzo[b]furan, benzo-[b]thiophene, indole, and naphthalene is described. All compounds showed a similar level of activity as TxA2 synthetase inhibitors in vitro, having IC50 values between 1 and 7 X 10(-8) M. In the cases examined, compounds had, at most, only negligible activity against PGI2 synthetase, cyclooxygenase, and steroid 11 beta-hydroxylase. The benzo[b]thiophenes generally showed the greatest potency in vivo, and compounds 72, 73, and 75 caused almost complete inhibition of thromboxane production for 6 h after oral administration of 0.5 mg/kg to conscious dogs. In the case of 73 and 75, thromboxane production was still inhibited by 80% after 24 h.

Animals↗
PubMed2003

Orally active analogues of the dopaminergic prodrug 6-(N,N-di-n-propylamino)-3,4,5,6,7,8-hexahydro-2H-naphthalen-1-one: synthesis and pharmacological activity.

A series of analogues of 6-(N,N-di-n-propylamino)-3,4,5,6,7,8-hexahydro-2H-naphthalen-1-one (6), an enone prodrug of the mixed DA D(1)/D(2) agonist 5,6-diOH-DPAT (2), was synthesized. The pharmacological profiles of these new enones and their in vivo pharmacological activities were investigated in the Ungerstedt rat rotation model for Parkinson's disease. At 0.1 mg kg(-1) po, the N-methyl-N-n-propyl (12) and the N-ethyl-N-propyl (13) analogues induced pronounced and long lasting pharmacological effects. The pharmacological profile of enone 12 was found to be similar to that of 6, while enone 13 was significantly more potent than 6 (p < 0.01). Analyses of rat brains after the administration of (-)-6 and 13 indicated the presence of hydroxylated metabolites of the parent enones. It is speculated that such metabolites are alpha'-hydroxylated enones that may constitute the first step in the formation of the corresponding catechols.

2-Naphthylamine↗
PubMed2003

Orally active oxime derivatives of the dopaminergic prodrug 6-(N,N-di-n-propylamino)-3,4,5,6,7,8-hexahydro-2H-naphthalen-1-one. Synthesis and pharmacological activity.

A series of racemic and enantiomerically pure oxime derivatives of the potential anti-Parkinson prodrug 6-(N,N-di-n-propylamino)-3,4,5,6,7,8-hexahydro-2H-naphthalen-1-one (1) were synthesized and pharmacologically evaluated. The oximes induced rotational behavior in the Ungerstedt rat rotation model for Parkinson's disease after oral administration. Especially the unsubstituted oxime ((-)-3) and the acetyl-oxime ((-)-10) induced a pronounced and long lasting effect. In this model, large individual differences were observed in responsiveness to treatment between rats. Though less potent than the parent prodrug, the oxime derivatives of (+/-)-1 and (-)-1 can be orally active, acting as cascade prodrugs.

Administration, Oral↗
PubMed2004

4-(tetralin-1-yl)- and 4-(naphthalen-1-yl)alkyl derivatives of 1-cyclohexylpiperazine as sigma receptor ligands with agonist sigma2 activity.

Several 1-cyclohexylpiperazine derivatives related to sigma(2) receptor ligand 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine (33, K(i) = 0.34 nM) were synthesized and tested in radioligand binding assays, to attempt a structure-affinity relationship study. Intermediate alkyl chain length and methoxyl group position on the tetralin nucleus were varied. A few naphthalene analogues were also prepared. High affinities were found in sigma(2) receptor binding for almost all compounds, some of which displayed K(i) values in subnanomolar range, but low sigma(2)/sigma(1) selectivities were found. The highest sigma(2) affinities were displayed by compounds with an intermediate alkyl chain of three (32 and 43) or five methylenes (39 and 46). Quite high sigma(1) receptor affinity was found for compounds with a four-methylene chain; 36 (K(i) = 0.036 nM) and 45 (K(i) = 0.22 nM) displaying good sigma(1)/sigma(2) selectivity (406- and 139-fold, respectively). Moreover, homologues of compound 33 displayed also satisfactory selectivities over dopamine D(2)-like, serotonin 5-HT(3), and adrenergic alpha(1) receptors. These compounds and a few others were tested in the inhibition of the electrically evoked contractions in guinea pig bladder and were demonstrated to be full sigma(2) agonists. The activity values correlated well to the affinity scale (EC(50) in microM range). 33 and related compounds are proposed as a class of potential antineoplastic and PET diagnosis agents.

Animals↗
PubMed2005

Heteroaryl-substituted naphthalenes and structurally modified derivatives: selective inhibitors of CYP11B2 for the treatment of congestive heart failure and myocardial fibrosis.

Recently we proposed inhibition of aldosterone synthase (CYP11B2) as a novel strategy for the treatment of congestive heart failure and myocardial fibrosis. In this study the synthesis and biological evaluation of heteroaryl-substituted naphthalenes and quinolines (1-31) is described. Key step for the preparation of the compounds was a Suzuki cross-coupling. Activity of the compounds was determined in vitro using human CYP11B2 and selectivity was evaluated toward the human steroidogenic enzymes CYP11B1, CYP19, and CYP17. A large number of highly active and selective inhibitors of CYP11B2 was identified. The most active inhibitor was the 6-cyano compound 8 (IC50 = 3 nM) showing a competitive type of inhibition (K(i) value = 1.9 nM). The 6-ethoxy derivative 5 was found to be the most selective CYP11B2 inhibitor (IC50 = 12 nM; K(i) value = 8 nM; CYP11B1 IC50 = 5419 nM; selectivity factor = 451), showing no inhibition of human CYP3A4 (50 nM) and CYP2D6 (20 nM). Docking and molecular dynamics studies using our homology modeled CYP11B2 structure with selected compounds were performed. Caco-2 cell experiments revealed a large number of medium and highly permeable compounds and metabolic studies with 2 using rat liver microsomes showed sufficient stability.

Aromatase↗