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Recent Applications of Gold Catalysis in Organic Synthesis
No full textThe catalysis of organic reactions by gold-catalysts has received in the past only little attention because of the preconceived opinion that gold is expensive and inert. The successful application of supported gold catalysts to pollution abatement changed this assessment and spurred on the explosion of interest in gold catalysis towards organic synthesis. Supported Au catalyst and homogeneous gold(III)-catalysts are effective in oxidation processes based on the most attractive oxidant. O-2/air, that proceed at a satisfactory rate at room temperature. selectively. and without rapid catalyst decomposition. Gold (III) salts are very effective catalysts for amination reaction of carbonyl compounds. The regio-/chemoselective interaction to the acetylenic bond is another of the more interesting features of gold catalysis. Activation of alkynes towards nucleophilic attack proved that gold salts are soft, exceptionally carbophilic Lewis acids. The dual role of Au(III) as a Lewis acid and as a transition-metal catalyst accomplished the synthesis of a variety of heterocycles through domino reactions
Multimodal techniques in magnetic resonance: Experimental apparatus for in vivo EPRI and PEDRI
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Full text linkWe 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
A new green approach to the Friedlander synthesis of quinolines
No full textA new approach to the Friedländer synthesis of quinolines is described. Polysubstituted quinolines are readily prepared under milder conditions than in other existing methods through a gold(III)-catalysed sequential condensation/annulation reaction of o-amino aromatic carbonyls and ketones containing active methylene groups
Conversion of Homochiral Amines and alpha-Amino esters to their Chiral 1,2,3,5-Substituted Pyrrole Derivatives via Gold-Catalyzed Amination/Annulation Reactions Of 2-Propynyl-1,3-Dicarbonyl Compounds
No full textHomochiral primary amines, amino alcohols and alpha -amino esters have been reacted with 2-propynyl-1,3-dicarbonyl compounds under gold catalysis leading to 1,2,5-trisubstituted 3-acylpyrrole derivatives in moderate to high yields and high enantiomeric excess
Gold-catalyzed sequential amination/annulation reactions of 2-propynyl-1,3-dicarbonyl compounds
No full textThe gold(III)-catalyzed sequential amination/annulation reaction of 2-propynyl-1,3-dicarbonyl compounds 1 with primary amines 2 produces 1,2,3,5-substituted pyrroles 4 in moderate to high yields
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