1,721,002 research outputs found
Catalyst-, solvent- and desiccant-free three-component synthesis of novel C-2,N-3 disubstituted thiazolidin-4-ones
Get PDFHerein it is provided an efficient, environmentally friendly and one-pot procedure for the synthesis of a library of new and diversely substituted 1,3-thiazolidin-4-ones in short reaction times and good yields through a solvent-, catalyst- and desiccant-free three-component process. Reactions proceeded by treatment of primary benzyl(aryl)amines with aromatic aldehydes (and ketones) and 2-mercaptoacetic acid acting as both reagent and self-catalyst. All reactions were performed in sand bath instead of the commonly used oil bath avoiding the generation of undesired volatile materials proceeding of the thermal decomposition of the oils. IR, Mass and NMR experiments as well as X-ray diffraction confirmed structures of the obtained products.Fil: Abonia, Rodrigo. Universidad del Valle; ColombiaFil: Castillo, Juan. Universidad de los Andes; Colombia. Universidad del Valle; ColombiaFil: Insuasty, Braulio. Universidad del Valle; ColombiaFil: Quiroga, Jairo. Universidad del Valle; ColombiaFil: Sortino, Maximiliano Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Orgánica. Área Farmacognosia; ArgentinaFil: Nogueras, Manuel. Universidad de Jaén; EspañaFil: Cobo, Justo. Universidad de Jaén; Españ
(E)-1-(5-Methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)-3-(naphthalen-2-yl)prop-2-en-1-one
Get PDFA reaction of equimolar equivalents of 2-naphthaldehyde (1) and 1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethan-1-one (2) in ethanolic sodium hydroxide at 20 °C for 4 h gave (E)-1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)-3-(naphthalen-2-yl)prop-2-en-1-one (3) in 92% yield. Nuclear magnetic resonance spectroscopy and single-crystal X-ray diffraction were used to establish the structure of 3
Synthesis of 3-aryl-1,2,4-benzotriazines via intramolecular cyclization of solid-supported o-hydrazidoanilines
Get PDFAn efficient solid-phase protocol for the rapid generation of libraries of biologically promising 1,2,4-benzotriazines, including amino acid-derived components, is described.Fil: Cortés, Edwar. Universidad del Valle; ColombiaFil: Mendez, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Mata, Ernesto Gabino. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Abonia, Rodrigo. Universidad del Valle; ColombiaFil: Quiroga, Jairo. Universidad del Valle; ColombiaFil: Insuasty, Braulio. Universidad del Valle; Colombi
(Z)-2-(1-(5-Methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethylidene)-N-phenylhydrazine-1-carbothioamide
Get PDFReaction of equimolar equivalents of 1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethan-1-one (1) and N-phenylhydrazinecarbothioamide (2) in boiling ethanol containing a catalytic amount of concentrated hydrochloric acid for 4 h gave (Z)-2-(1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethylidene)-N-phenylhydrazine-1-carbothioamide (3) with 88% yield. The structure of 3 was established using single-crystal X-ray diffraction and magnetic resonance spectroscopy
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
Synthesis of novel thiazole-based 8,9-dihydro-7H-pyrimido[4,5-b][1,4]diazepines as potential antitumor and antifungal agents
Get PDFA new series of novel thiazole-based 8,9-dihydro-7H-pyrimido[4,5-b][1,4]diazepines 6a–g and 7a–g were obtained with high regioselectivity from the reaction of triamino- or tetraaminopyrimidines 4 and 5 with α,β-unsaturated carbonyl compounds 3a–g based on 2,4-dichlorothiazol-5-carbaldehyde 1. Twelve of the synthesized compounds were selected and tested by US National Cancer Institute (NCI) for their antitumor activity against 60 different human tumor cell lines. Compounds 7d and 7g showed important GI50 ranges of 1.28–2.98 μM and 0.35–2.78 μM respectively under in vitro assays. In addition, 6a–g and 7a–g were tested for antifungal properties against the clinical important fungi Candida albicans and Cryptococcus neoformans. Although these compounds showed moderate activities against C. albicans, the 2-amino derivatives 7a–g and mainly 7a and 7b, showed high activity against standardized and clinical isolates of C. neoformans with MIC50 = 7.8–31.2 μg/mL, MIC80 = 15.6–31.2 μg/mL and MIC100 = 15.6–62.5 μg/mL. In addition, since both compounds were fungicide rather than fungistatic these thiazole-based 8,9-dihydro-7H-pyrimido[4,5-b][1,4]diazepines appear as good candidates for further development not only as antifungal but also as antitumor drugs.Fil: Ramírez, Juan. Universidad del Valle. Departamento de Química; ColombiaFil: Svetaz, Laura Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnológico Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Orgánica. Area Farmacognosia; ArgentinaFil: Quiroga, Jairo. Universidad del Valle. Departamento de Química; ColombiaFil: Abonia, Rodrigo. Universidad del Valle. Departamento de Química; ColombiaFil: Raimondi, Marcela. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Orgánica. Area Farmacognosia; ArgentinaFil: Zacchino, Susana. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Orgánica. Area Farmacognosia; ArgentinaFil: Insuasty, Braulio. Universidad del Valle. Departamento de Química; Colombi
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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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