Search results for "Fluorene"
showing 10 items of 82 documents
Determination of amphetamines in hair by integrating sample disruption, clean-up and solid phase derivatization
2016
The utility of matrix solid phase dispersion (MSPD) for the direct analysis of amphetamines in hair samples has been evaluated, using liquid chromatography (LC) with fluorescence detection and precolumn derivatization. The proposed approach is based on the employment of MSPD for matrix disruption and clean-up, followed by the derivatization of the analytes onto the dispersant-sample blend. The fluorogenic reagent 9-fluorenylmethyl chloroformate (FMOC) has been used for derivatization. Different conditions for MSPD, analyte purification and solid phase derivatization have been tested, using amphetamine (AMP), methamphetamine (MET), ephedrine (EPE) and 3,4-methylenedioxymethamphetamine (MDMA)…
Monoradicals and Diradicals of Dibenzofluoreno[3,2-b]fluorene Isomers: Mechanisms of Electronic Delocalization
2020
The preparation of a series of dibenzo- and tetrabenzo-fused fluoreno[3,2-b]fluorenes is disclosed, and the diradicaloid properties of these molecules are compared with those of a similar, previously reported series of anthracene-based diradicaloids. Insights on the diradical mode of delocalization tuning by constitutional isomerism of the external naphthalenes has been explored by means of the physical approach (dissection of the electronic properties in terms of electronic repulsion and transfer integral) of diradicals. This study has also been extended to the redox species of the two series of compounds and found that the radical cations have the same stabilization mode by delocalization…
Fluorescence of Newo-Carborane Compounds with Different Fluorophores: Can it be Tuned?
2014
Two sets of o-carborane derivatives incorporating fluorene and anthracene fragments as fluorophore groups have been successfully synthesized and characterized, and their photophysical properties studied. The first set, comprising fluorene-containing carboranes 6-9, was prepared by catalyzed hydrosilylation reactions of ethynylfluorene with appropriate carboranylsilanes. The compound 1-[(9,9-dioctyl-fluorene-2-yl)ethynyl]carborane (11) was synthesized by the reaction of 9,9-dioctyl-2-ethynylfluorene and decaborane (B10H14). Furthermore, reactions of the lithium salt of 11 with 1 equivalent of 4-(chloromethyl)styrene or 9-(chloromethyl)anthracene yielded compounds 12 and 13. Members of the se…
Stable expression of rat cytochrome P450IA2 cDNA and hydroxylation of 17β-estradiol and 2-aminofluorene in V79 Chinese hamster cells
1991
In continuation of our work toward the establishment of a working cell bank for metabolic and toxicological studies, V79 Chinese hamster cells were genetically engineered for stable expression of rat cytochrome P450IA2. Full-length cDNA encoding rat P450IA2 was obtained by searching a cDNA library made from Aroclor 1254-induced rat liver mRNA and by joining a small 5'-end fragment to a fragment containing the rest of the cDNA. The sequence of the cDNA was confirmed by DNA sequencing and comparison to a previously published cDNA sequence. The reconstructed full-length cDNA was inserted into a simian virus 40 early promoter-containing eukaryotic expression vector and cotransferred with the ne…
Use of HepG2 cell line for direct or indirect mutagens screening: comparative investigation between comet and micronucleus assays.
2003
International audience; In the present study, DNA-damage and clastogenic or aneugenic effects of genotoxic compounds were examined in a metabolically competent human cell line (HepG2 cells) using the micronucleus and the comet assays. Compounds with various action mechanisms were tested: direct mutagens such as 4-nitroquinoline-N-oxide (4-NQO) and methyl methanesulfonate (MMS) and indirect mutagens requiring biotransformation to be active such as N-nitrosodimethylamine (NDMA), benzo[a]pyrene (B[a]P) and 2-acetylaminofluorene (2-AAF). The compounds were first tested for cytotoxicity by measuring their effects on RNA synthesis inhibition in HepG2 cells. 4-NQO, B[a]P and 2-AAF were the most po…
New polyamine drugs as more effective antichagas agents than benznidazole in both the acute and chronic phases.
2018
Abstract Despite the continuous research effort that has been made in recent years to find ways to treat the potentially life threatening Chagas disease (CD), this remains the third most important infectious disease in Latin America. CD is an important public health problem affecting 6–7 million people. Since the need to search for new drugs for the treatment of DC persists, in this article we present a panel of new polyamines based on the tripodal structure of tris(2-aminomethyl)amine (tren) that can be prepared at low cost with high yields. Moreover, these polyamines present the characteristic of being water-soluble and resistant to the acidic pH values of stomach, which would allow their…
Rhodanine-based dyes absorbing in the entire visible spectrum
2017
A series of new broad-absorbing dyes based on rhodanine derivatives conjugated with triarylamines using Q5 a fluorene backbone was synthesized. Spectroscopic and electrochemical characterizations, along with theoretical calculations at the B3LYP/cc-pVDZ level, revealed interesting properties of the dyes, which make the dyes efficiently absorb in the entire visible spectrum.
Pyrolytic formation of polyaromatic hydrocarbons from steroid hormones
2011
Author's version of an article published in Food Chemisty, 124 (4), 1466-1472. Also available from the publisher: hhtp://dx.doi.org/10.1016/j.foodchem.2010.07.109 Four steroid hormones, namely androsterone, cholesterol, estrone and estradiol, have been pyrolysed at 300, 400 and 500 °C and the pyrolysates from these have been analysed by GC-MS. The results indicate that these formed different products under the pyrolysis and most of them evolved into polycyclic aromatic hydrocarbons during their residence in the pyrolysis chamber at high temperatures. The products from the pyrolysates, at all temperatures, were analysed for similarities and differences using multivariate data analysis. The p…
Gas—liquid chromatographic analyses
1985
Abstract The gas chromatographic retention behaviour of methylethyl, 1-methylpropyl, 2-methylpropyl, 1,2-dimethylpropyl, 1-methylbutyl and 3-methylbutyl esters of benzoic and o-, m- and p-chlorobenzoic acids on low-polarity (SE-30) and polar (OV-351) capillary columns under several temperature-programmed and isothermal conditions is reported. The retention data and the Kovats retention indices for all 24 components are given and the separation of a complex mixture is discussed. The retention index increments have been used to examine the effects of chain branching and chlorine substitution. The results are compared with those for n-alkyl benzoates and monochlorobenzoates.
Efficacy of Ozonation Treatments of Smoked Fish for Reducing Its Benzo[a]pyrene Concentration and Toxicity
2017
Ozone is widely used in food processing, for example, to decompose mycotoxins or pesticide residues, to extend the shelf life of products, and for sanitation. The objective of this study was to assess the possibility of expanding the application of ozone for oxidative degradation of polycyclic aromatic hydrocarbons (PAHs). The evaluation was conducted by ozonation of a benzo[a]pyrene (BaP) standard solution and smoked fish (sprats) contaminated with PAHs. The effect of ozonation was immediate in the BaP solution; 89% of this toxic compound was decomposed after only 1 min of treatment. However, the impact of ozonation on the smoked sprats was less pronounced, even after prolonged treatment. …