Search results for "Paraffins"
showing 10 items of 10 documents
Analytical procedures for short chain chlorinated paraffins determination - How to make them greener?
2019
Abstract The aim of the following paper was to gather current scientific information about the analytical protocols dedicated to measuring the content level of short-chain chlorinated paraffins (SCCPs) in various types of environmental samples. Moreover, the data about the basic validation parameters of applied procedures for SCCPs determination are listed. The main issue which is highlighted in the paper is the possibility of the application of green analytical chemistry (GAC) principals in the SCCPs measuring process to reduce the environmental impact of the applied methodology. Analytical methods dedicated to SCCPs determination contain a significant number of steps and require advanced …
Enantioselective addition of nitromethane to α-keto esters catalyzed by copper(ii)–iminopyridine complexes
2008
The copper complex of a chiral iminopyridine easily prepared from (R)-(-)-fenchone and picolylamine catalyzes the enantioselective Henry (nitroaldol) reaction between nitromethane and alpha-keto esters. Good yields and modest to good enantioselectivities are obtained for a wide range of alpha-keto esters, bearing aromatic, alkyl or alkenyl groups attached to the ketone carbonyl group.
Activation of propane 2-nitronate to a genotoxicant in V79-derived cell lines engineered for the expression of rat hepatic sulfotransferases
1999
2-Nitropropane (2-NP) is a genotoxic hepatocarcinogen in rats. The genotoxicity of the compound has been attributed to a sulfotransferase-mediated formation of DNA-reactive species from the anionic form of 2-NP, propane 2-nitronate (P2N). Several observations have suggested that sulfotransferases (SULTs) 1A1 and/or 1C1 may be important in the activation of P2N to a genotoxicant in rat liver, but a definite proof is lacking. In order to identify the sulfotransferase(s) of rat liver that are capable of activating P2N, we have investigated the genotoxicity of P2N in various V79-derived cell lines engineered for expression of individual forms of rat hepatic sulfotransferases. Genotoxicity was a…
Dietary lycopene decreases the initiation of liver preneoplastic foci by diethylnitrosamine in the rat
1997
To test whether carotenoids can modulate the initiation of liver preneoplasia by diethylnitrosamine (DEN) or by 2-nitropropane (2-NP) in a sequential protocol of hepatocarcinogenesis, male weanling rats were fed for three or four weeks (respectively) diets containing beta-carotene, canthaxanthin, astaxanthin, or lycopene (300 mg/kg diet) or an excess of vitamin A (15,000 retinol equivalents/kg diet) or were treated intraperitoneally with 3-methylcholanthrene. During this period, all rats were injected intraperitoneally with the initiator carcinogen, either 2-NP (6 times at 100 mg/kg body wt) or DEN (once at 100 mg/kg body wt). Three weeks after the termination of carotenoid or vitamin A fee…
Design, synthesis, and biological evaluation of nonsteroidal cycloalkane[d]isoxazole-containing androgen receptor modulators.
2012
We report here the design, preparation, and systematic evaluation of a novel cycloalkane[d]isoxazole pharmacophoric fragment-containing androgen receptor (AR) modulators. Cycloalkane[d]isoxazoles form new core structures that interact with the hydrophobic region of the AR ligand-binding domain. To systematize and rationalize the structure-activity relationship of the new fragment, we used molecular modeling to design a molecular library containing over 40 cycloalkane[d]isoxazole derivatives. The most potent compound, 4-(3a,4,5,6,7,7a-hexahydrobenzo[d]isoxazol-3-yl)-2-(trifluoromethyl)benzonitrile (6a), exhibits antiandrogenic activity significantly greater than that of the most widely used …
Finely Tuned Temperature-Controlled Cargo Release Using Paraffin-Capped Mesoporous Silica Nanoparticles
2011
[EN] Trapped: Mesoporous silica nanoparticles were loaded with a fluorescent guest and functionalized with octadecyltrimethoxysilane. The alkyl chains interact with paraffins, which build a hydrophobic layer around the particle (see picture). Upon melting of the paraffin, the guest molecule is released, as demonstrated in cells for the guest doxorubicin. The release temperature can be tuned by choosing an appropriate paraffin. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Carbon nanorings: A challenge to theoretical chemistry
2006
High-level quantum-chemical methods show that the binding in the inclusion complex of hexamethylbenzene (HMB) in 6-cycloparaphenilacetylene (6-CPPA) cannot be explained only in terms of electrostatic interactions - caused by the polarization associated to curved Ï-conjugated systems - and the inclusion of dispersion forces is definitely needed. The theoretical description of van der Waals interactions is notoriously complicated and in fact some DFT methods cannot even predict the existence of the relatively small supramolecular nanoring studied here. However, ab initio MP2 calculations agree with experimental data and show that, in the considered complex, the HMB fragment is placed at the …
The impact of baking on chlorinated paraffins: Characterization of C10–C17 chlorinated paraffins in oven-baked pastry products and unprocessed pastry…
2019
Abstract This study presents an HPLC–ESI–Q–TOF method for simultaneous quantification of short-chain chlorinated paraffins (SCCPs, C10–13) and an additional characterization of medium-chain chlorinated paraffins (MCCPs, C14–17) in oven-baked pastry products (n = 38) and unprocessed pastry dough material (n = 15). Almost 2 times higher SCCP levels were found in the dough material. ΣSCCP concentrations in products ranged from 0.3 ng g−1 to 23.0 ng g−1 (mean: 6.3 ng g−1), while the results for dough ranged from 5.8 ng g−1 to 22.8 ng g−1 (mean: 12.9 ng g−1). Regardless of the sample matrix, the most abundant CP homologue groups were hepta- and octa-chlorinated undecanes and dodecanes. The avera…
Novel ruthenium methylcyclopentadienyl complex bearing a bipyridine perfluorinated ligand shows strong activity towards colorectal cancer cells
2017
Three new compounds have been synthesized and completely characterized by analytical and spectroscopic techniques. The new bipyridine-perfluorinated ligand L1 and the new organometallic complex [Ru(η 5 -MeCp)(PPh 3 ) 2 Cl] (Ru1) crystalize in the centrosymmetric triclinic space group P1¯. Analysis of the phenotypic effects induced by both organometallic complexes Ru1 and [Ru(η 5 -MeCp)(PPh 3 )(L1)][CF 3 SO 3 ] (Ru2), on human colorectal cancer cells (SW480 and RKO) survival, showed that Ru2 has a potent anti-proliferative activity, 4–6 times higher than cisplatin, and induce apoptosis in these cells. Data obtained in a noncancerous cell line derived from normal colon epithelial cells (NCM46…
Theoretical calculation of the vibrational spectra of cis-cis-cyclooctadienes in the vapour phase.
2000
The theoretical infrared spectra of 1,3-cis-cis-cyclooctadiene (1,3-COD) and 1,5-cis-cis-cyclooctadiene (1,5-COD), were obtained by ab initio MO calculations at Hartree-Fock level. The results were compared with the available IR experimental spectra of 1,3- and 1,5-COD. The apparent agreement between theoretical and experimental data allows us to exploit two bands, found only in the case of the theoretical spectrum of 1,4-COD, as a tool for identifying 1,4-COD during its synthesis.