Search results for "Derivative"
showing 10 items of 1074 documents
Multidrug resistance reverting activity and antitumor profile of new phenothiazine derivatives
2008
Abstract A series of easily affordable phenothiazine derivatives bearing a rigid but-2-ynyl amino side chain were synthesized and tested to evaluate the MDR reverting activity and full antitumor profile. Some compounds endowed with remarkable MDR reverting effect were identified, and the most active one ( 6c ) was shown to increase doxorubicin retention in multidrug resistant cells, suggesting a direct interaction with P-glycoprotein. Furthermore, a broad range of cellular activities were observed for different compounds. In particular, the ability of some derivatives to induce antiproliferative effects on resistant cell lines and to interfere with the G 1 phase of the cell cycle, a phase u…
Comparative studies of the Pschorr reaction in the pyrazole series. Access to the new dibenzo[e,g]pyrazolo[1,5-a][1,3]diazocine system of pharmaceuti…
2008
The diazonium tetrafluoroborate 11 obtained from 2-amino-N-methyl-N-(1-phenyl-3- methylpyrazol-5-yl)benzamide was transformed in dry acetonitrile via an ionic or radical pathway. Differences were observed with respect to ionic or radical transformations in aqueous media of the analogous diazonium hydrogen sulfate 1 derived from the same amine. In acetonitrile solution, the ionic pathway was characterized by an increased yield of 1,4-dimethyl- 3-phenyl-pyrazolo(3,4-c)isoquinolin-5-one 4 and by the formation of its isomer, the new derivative 7,9-dimethyldibenzo(e,g)pyrazolo(1,5-a)(1,3)diazocin-10(9H)-one 12. When the reaction followed a radical pathway, the pyrazolo(3,4-c)isoquinoline derivat…
Finite-size effects of Kirkwood–Buff integrals from molecular simulations
2017
The modelling of thermodynamic properties of liquids from local density fluctuations is relevant to many chemical and biological processes. The Kirkwood–Buff (KB) theory connects the microscopic structure of isotropic liquids with macroscopic properties such as partial derivatives of activity coefficients, partial molar volumes and compressibilities. Originally, KB integrals were formulated for open and infinite systems which are difficult to access with standard Molecular Dynamics (MD) simulations. Recently, KB integrals for finite and open systems were formulated (J Phys Chem Lett. 2013;4:235). From the scaling of KB integrals for finite subvolumes, embedded in larger reservoirs, with the…
Elaboration of Trans-Resveratrol Derivative-Loaded Superparamagnetic Iron Oxide Nanoparticles for Glioma Treatment
2019
In this work, new nanohybrids based on superparamagnetic iron oxide nanoparticles (SPIONs) were elaborated and discussed for the first time as nanovectors of a derivative molecule of trans-resveratrol (RSV), a natural antioxidant molecule, which can be useful for brain disease treatment. The derivative molecule was chemically synthesized (4&rsquo
Complexes of organometallic compounds
1972
Abstract The configurations of (CH 3 ) 3 PbNCS, (C 6 H 5 ) 3 PbNCS, (C 6 H 5 ) 2 Pb(NCS) 2 , (C 6 H 5 ) 3 Pb(NCS) 2 − and (C 6 H 5 ) 2 Pb(NCS) 4 2− have been investigated in the solid and (except for the insoluble diphenyl derivative) in solution. From infrared spectroscopy it is deduced that the compounds are isothiocyanates in both states, and there is evidence for a polymeric nature of the solid neutral species involving bridging through NCS. PMR and osmometric investigations show that five-coordinate species (CH 3 ) 3 Pb(NCS)·(CH 3 ) 2 CO are present in acetone solution. Possible configurations are discussed.
Development of a versatile, easy and rapid atmospheric monitor for benzene, toluene, ethylbenzene and xylenes determination in air
2009
Abstract A new procedure for the passive sampling in air of benzene, toluene, ethylbenzene and xylene isomers (BTEX) is proposed. A low-density polyethylene layflat tube filled with a mixture of solid phases provided a high versatility tool for the sampling of volatile compounds from air. Several solid phases were assayed in order to increase the BTEX absorption in the sampler and a mixture of florisil and activated carbon provided the best results. Direct head-space-gas chromatography–mass spectrometry (HS-GC–MS) measurement of the whole deployed sampler was employed for a fast determination of BTEX. Absorption isotherms were used to develop simple mathematical models for the estimation of…
Effects of cyclooxygenase-1/cyclooxygenase-2 inhibition on leukocyte/endothelial cell interactions in the rat mesentery.
2002
Nonsteroidal anti-inflammatory drugs (NSAID) inhibit cyclooxygenase activity and cause gastrointestinal damage in part by promoting leukocyte accumulation in the mucosa. Our aim was to evaluate the effects of selective blockade of the isoenzymes cyclooxygenase-1 and cyclooxygenase-2 on leukocyte adhesion in vivo. Leukocyte/endothelial cell interactions were examined in rat mesenteric venules before and after treatment with indomethacin, SC-560 (5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethylpyrazole, cyclooxygenase-1 inhibitor), DFP (5,5-dimethyl-3-(2-propoxy)-4-(4-methanesulfonyl)-2(5H)-furanone, cyclooxygenase-2 inhibitor), or SC-560 plus DFP (20 mg/kg, i.v. each). Indomethacin i…
Variational formulations and extra boundary conditions within stress gradient elasticity theory with extensions to beam and plate models
2016
Abstract The principle of minimum total potential energy and the primary principle of virtual power for stress gradient elasticity are presented as kinematic type constructs dual of analogous static type principles from the literature (Polizzotto, 2014; Polizzotto, 2015a). The extra gradient-induced boundary conditions are formulated as “boundary congruence conditions” on the microstructure’s deformation relative to the continuum, which ultimately require that the normal derivative of the stresses must vanish at the boundary surface. Two forms of the governing PDEs for the relevant boundary-value problem are presented and their computational aspects are discussed. The Timoshenko beam and th…
1,2-Methyl shift in the reaction of 4,7-dihydro-4,5-dimethyl-7-phenyl-(1,2,4)-triazolo[1,5-a]pyrimidine with tosyl azide
2000
The reaction of the heterocyclic enamine 1 with tosyl azide (2) leads to the tosylimino derivative 4 of 1,2,4-triazolo[1,5-a]pyrimidine. The extrusion of nitrogen from the primary adduct 3 is followed by a 1,2-shift of a methyl group. The structure determination of 4 is based on 1H and 13C nmr spectra including NOE measurements.
Oxidative stress induces distinct physiological responses in the two Trebouxia phycobionts of the lichen Ramalina farinacea
2010
† Background and Aims Most lichens form associations with Trebouxia phycobionts and some of them simultaneously include genetically different algal lineages. In other symbiotic systems involving algae (e.g. reef corals), the relative abundances of different endosymbiotic algal clades may change over time. This process seems to provide a mechanism allowing the organism to respond to environmental stress. A similar mechanism may operate in lichens with more than one algal lineage, likewise protecting them against environmental stresses. Here, the physiological responses to oxidative stress of two distinct Trebouxia phycobionts (provisionally named TR1 and TR9) that coexist within the lichen R…