Search results for "ANTHRACENE"
showing 10 items of 171 documents
Synthesis of oligomeric chains with 9,10‐dihydroanthracene units by carbanion alkylation
1988
Deprotonation of 9,10-dihydroanthracene (2) affords the monoanion 6 which is subjected to alkylation reactions with mono and bifunctional electrophiles. Crucial intermediates in syntheses using 6 are 9-(3-bromopropyl)-9,10-dihydroanthracene (7) and 1,3-bis(9,10-dihydro-9-anthryl)propane (9) since they provide access to linear oligomers in which 9,10-dihydroanthracene units are linked by trimethylene groups. The alkylation processes of these species can be extended to the structurally related polymer 4. The regio- and stereoselectivity of the alkylation reactions are investigated by 1H- and 13C-NMR spectroscopy. Oligomere Ketten mit 9,10-Dihydroanthracen-Einheiten durch Carbanionalkylierung …
Hard Cap Espresso Machines in Analytical Chemistry: What Else?
2016
A hard cap espresso machine has been used in combination with liquid chromatography with molecular fluorescence detection for the determination of polycyclic aromatic hydrocarbons (PAHs) from contaminated soils and sediments providing appropriate extraction efficiencies and quantitative results. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benz[b]fluoranthene, benz[k]fluoranthene, benz[a]pyrene, dibenz[a,h]anthracene, benz[ghi]perylene, and indeno[1,2,3-cd]pyrene were used as target compounds. It should be mentioned that the pairs benz[a]anthracene-chrysene and dibenz[a,h]anthracene-benz[ghi]perylene peaks coelute under th…
Potentiometric, NMR, and Fluorescence-Emission Studies on the Binding of Adenosine 5′-Triphosphate (ATP) by Open-Chain Polyamine Receptors Containing…
2003
The interaction in aqueous solution of adenosine 5′-triphosphate (ATP) with a series of open-chain polyamines linked at one or both ends to anthrylmethyl or naphthylmethyl fragments was followed by potentiometric titration, 1H-, 13C-, and 31P-NMR spectroscopy, and by steady-state fluorescence measurements. The results revealed greater stabilities for the compounds containing one anthracene moiety than for those with one naphthalene moiety, the stabilities of the compounds with both ends N-substituted with naphthylmethyl groups being close to those containing just one anthrylmethyl unit. The 1H-NMR spectra showed that in all systems, there is involvement of π-π stacking interactions in the s…
Overexpression of bone morphogenetic protein-6 (BMP-6) in murine epidermis suppresses skin tumor formation by induction of apoptosis and downregulati…
2001
Bone morphogenetic protein-6 (BMP-6) is a member of the transforming growth factor-beta superfamily. In murine skin, BMP-6 is highly expressed in postmitotic keratinocytes from day 15.5 p.c. till day 6 p.p. Expression in adult skin remains at very low levels, but pathological conditions such as wounding induce the expression of BMP-6. We demonstrate that tumor promotion by TPA (12-O-tetradecanoylphorbol-13-acetate) also induces expression of BMP-6 in suprabasal keratinocytes. This induction is due to post-transcriptional regulation since the level of BMP-6 mRNA remained unchanged. We performed two-stage skin carcinogenesis experiments with transgenic mice epidermally overexpressing BMP-6. T…
DFT studies of COOH tip-functionalized zigzag and armchair single wall carbon nanotubes
2011
Structure and energy calculations of pristine and COOH-modified model single wall carbon nanotubes (SWCNTs) of different length were performed at B3LYP/6-31G* level of theory. From 1 to 9 COOH groups were added at the end of the nanotube. The differences in structure and energetics of partially and fully functionalized SWCNTs at one end of the nanotube are observed. Up to nine COOH groups could be added at one end of (9,0) zigzag SWCNT in case of full functionalization. However, for (5,5) armchair SWCNT, the full functionalization was impossible due to steric crowding and rim deformation. The dependence of substituent attachment energy on the number of substituents at the carbon nanotube ri…
Bisdihydrodiols, rather than dihydrodiol oxides, are the principal microsomal metabolites of tumorigenic trans-3,4-dihydroxy-3,4-dihydrodibenz[a,h]an…
1994
Several studies on metabolism and biological activity of tumorigenic dibenz[a,h]anthracene (DBA) and its derivatives have led to the conclusion that the M-region dihydrodiol, trans-3,4-dihydroxy-3,4-dihydro-DBA (DBA-3,4-dihydrodiol), is the precursor of the ultimate mutagenic and tumorigenic metabolite of DBA with the presumed structure of a bay-region dihydrodiol oxide. Incubations of DBA-3,4-dihydrodiol (50 microM) with the microsomal hepatic fraction of Sprague-Dawley rats pretreated with Aroclor 1254 yielded more than 13 metabolites upon separation by HPLC. anti-3,4-Dihydroxy-1,2-epoxy-1,2,3,4-tetrahydro-DBA [0.27 nmol/(nmol of P450.15 min)] could be identified for the first time by UV …
A study of weathered coal spectroscopic properties
2017
Abstract Current coal industry causes significant environmental pollution and the most air pollution deaths in the world, making the development of new eco-friendly applications one of the top priorities. Coal contains up to 50 % humic substances (HS), the majority of which is humic acid (HA). HA is well known for its beneficial properties and thus compounds extracted from coal can be used to develop new applications. To address this issue, we assessed structural composition of coal HS by measuring their spectroscopic properties. As the result, obtained spectra can be used to identify information about the molecules and thus allowing describing the composition of HS. The purpose of this stu…
K-region oxides and imines derived from alkylated benz[α]anthracene congeners: synthesis, stability in aqueous media and mutagenicity
1994
The K-region oxides and imines of benz[a]anthracene, 1-methylbenz[a]anthracene, 7-methylbenz[a]anthracene, 7-ethylbenz[a]anthracene and 7,12-dimethylbenz[a]anthracene were synthesized and characterized (melting point, 1H-NMR and electron impact mass spectra, elemental analysis, IR spectroscopy). All 10 compounds showed high mutagenic activity in Salmonella typhimurium (reversion of his- strains TA97, TA98, TA100 and TA104). The arene imines were more potent than the corresponding arene oxides. Alkyl substitutions strongly influenced the activities. Furthermore, all compounds were more active when exposure took place in the absence of inorganic ions than when KCl (125 mM) was present. The in…
Luminescence properties of a cofacial dipalladium porphyrin dimer under argon and in the presence of dioxygen
2001
The preparation and luminescence properties of a dipalladium cofacial porphyrin dimer (DPA) Pd 2 (where DPA is the tetraanion of 1,8-bis(2,8,13,17-tetraethyl-3,7,12,18-tetramethylporphyrin-5-yl)anthracene) are reported and compared together with the photophysical behavior of the known monomeric (OEP)Pd and (TPP)Pd complexes. The effect of dioxygen in the presence and in the absence of the very bulky base, 1-t-butyl-5-phenylimidazole, is also investigated. The title dimer, (DPA) Pd 2, shows fluorescence and phosphorescence in the ps and ms time scale, respectively, with a global intensity lower than that of the porphyrin monomer analogues. The fluorescence sensitivity towards dioxygen quenc…
Morphological transformation and DNA adduct formation by dibenz[a,h]anthracene and its metabolites in C3H10T1/2CL8 cells.
1994
The major routes of metabolic activation of dibenz[a,h]-anthracene (DBA) have been studied in transformable C3H10T1/2CL8 (C3H10T1/2) mouse embryo fibroblasts in culture. The morphological transforming activities of three potential intermediates formed by metabolism of DBA by C3H10T1/2 cells, trans-3,4-dihydroxy-3,4-dihydro-DBA-(DBA-3,4-diol), trans-dihydroxy-3,4-dihydro-DBA-anti-1,2-oxide (DBA-3,4-diol-1,2-oxide) and DBA-5,6-oxide were determined. DBA-3,4-diol-1,2-oxide was a strong morphological transforming agent giving a mean of 73% dishes with Type II or III foci and 1.63 Type II and III foci per dish at 0.5 microgram/ml. DBA-3,4-diol produced a mean of 42% dishes with Type II or III fo…