1,720,977 research outputs found
Structural study of ribonucleotide reductase inhibitor hydrazones. Synthesis and X-ray diffraction analysis of a copper(II)-benzoylpyridine-2-quinolinyl hydrazone complex
No full textSingle crystals as yellow needles of N-(4,8-dimethyl-quinolin-2-yl)-N'-(1-pyridin-2-yl-ethylidene)-hydrazine, HL1, 1, and N-(4-methyl-quinolin-2-yl)-N'-(phenyl-pyridin-2-yl-methylene)-hydrazine, HL2, 2, were obtained from methanol (MeOH) and analyzed via X-ray diffraction (XRD). HL2 reacted with copper(II) acetate to produce a dark red powder that gave single crystals of [Cu(L-2)(OOCCH3)] center dot 0.9C(6)H(5)CH(3), 3 center dot 0.9C(6)H(5)CH(3) when recrystallized from toluene. The conformation of the N(quinolinyl,q)C(q)-N(H)N(imine,i)-C-C(pyridine,p)-N(p) grouping is trans,trans,trans,trans or tttt, and ttcc for 1 and 2, respectively, at the solid state, as revealed via single crystal X-ray diffraction. Thus, the structure of 1 has the methyl (hydrazone) group syn to the N-H bond and syn to the N(q) and N(p) atom. On the other side, the structure of 2 is stabilized by a strong intra-molecular N-Hcenter dot center dot center dotN hydrogen bond which involves the pyridyl nitrogen atom. The molecule 1 is almost planar, the torsion angles do not deviate more than 4 from the idealized values of 0 degrees and 180 degrees. In the structure of 2 the pyridyl ring is almost coplanar with the N(q)-C(q)-NH-N(i)-C system, whereas the phenyl (Ph) ring is twisted by ca. 55 degrees. The structure of 3 has the L-2 ligand as deprotonated at the N-N function and in a cttc conformation as opposite to the ttcc one found for pure 2. The metal center is coordinated through N(q), N(i), N(p) and through an oxygen atom from a carboxylate anion. The molecular modeling analysis of 1 and 2 (semi-empirical molecular orbital at Zerner's intermediate neglect of differential overlap (ZINDO/1) level and density functional theory (DFT) methods) gave good agreement with the X-ray structures. Semi-empirical quantum mechanics analysis of 3 allowed to assign the UV-Vis spectrum that is characterized by strong absorptions in the visible, UVA and UVB regions. Owing to the ribonucleotide reductase inhibitory activity of the ligand, to the ascertained anticancer activity shown previously by related copper(II)-hydrazone complexes, and to the oxygen radical scavenger activity of several copper(II)-complexes, 3 is potentially anticancer and anti-inflammatory
Chelating agents as potential antitumorals: alfa-(N)-heterocyclic hydrazones and bis-alfa-(N)-heterocyclic hydrazones
No full textA number of pyruvic acid and methylpyruvate alpha-(N)-heterocyclic hydrazones has been synthesized. Bis-heterocyclic hydrazones were obtained from reaction with pyruvic carboxaldehyde. Some complexes of Ni(II) were prepared and characterized as neutral complexes. All these compounds have been evaluated for cytotoxicity against P388 and HL-60 leukemia
On the isomerism/tautomerism of hydrazones. Crystal structures, study in solution and theoretical calculation of new series of α-N-heterocyclic hydrazones
No full texti.f. 1.92
New 1-[quinolyl(4)]-1,2,3-triazoles: synthesis and evaluation of antiinflammatory and analgesic properties. II
No full textSeveral 1-[quinolyl(4)]-1,2,3-triazoles were synthesized by 1,3-dipolar cycloaddition of 4-azidoquinolines with activated methylene compounds. The synthesized compounds, tested for antiinflammatory and analgesic activities, resulted moderately active as antiinflammatories, but with a very interesting analgesic activity, sometimes higher than that of indomethacin, used as reference drug. Some of the triazole derivatives were evaluated also as antimicrobial, but none of them exhibited activity
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
New quinoline derivatives: synthesis and evaluation for antiinflammatory and analgesic properties - Note I
No full textNew 4-anilinoquinoline-3-carboxylic acids, N-[3-carboxyquinolyl (4)]anthranilic acids and their corresponding esters were synthetized by reacting 4-chloro-3-carbethoxyquinolines with substituted anilines and methyl anthranilate respectively. All the compounds were tested for antiinflammatory and analgesic activities. Some derivatives showed a significant antiinflammatory activity comparable to that of indomethacin
New alfa -(N)-heterocyclic hydrazones: evaluation of anticancer, anti-HIV and antimicrobial activity
No full textPyrazolo[4,3-c]quinolines. Synthesis and specific inhibition of benzodiazepine receptor binding (Note I)
No full textA series of 2-arylpyrazolo[4,3-c] quinolin-3-one derivatives, bearing different substituents in the two aromatic rings, were prepared and tested for their ability to displace [H-3] flunitrazepam from rat brain membranes. Some compounds have shown an affinity for receptors comparable and sometimes higher than that of CGS series
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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