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Multicomponent Approach to Libraries of Substituted Dihydroorotic Acid Amides
No full textA process featuring a sequential multicomponent reaction followed by a regioselective postcyclization strategy was implemented for the facile synthesis of N,N'-disubstituted dihydroorotic acid amides under mild conditions. We obtained, for the first time, a library of 29 derivatives, encompassing 19 Nα-substituted-N4-dihydroorotyl-4-aminophenylalanine derivatives, a key residue of gonadotropin-releasing hormone antagonist Degarelix. The corresponding products were prepared from easily accessible starting materials in good to excellent yields with broad substrate scope
Multicomponent diversity oriented synthesis of multivalent glycomimetics containing hexafluorovaline
Get PDFThe chemoselective introduction of fluorinated moieties into biologically relevant scaffolds is now an
established strategy to modulate and to study the properties of molecular leads. In this article we propose,
for the first time, the diversity oriented synthesis of multivalent glycomimetics incorporating
hexafluorovaline through a straightforward multicomponent sequential process, which occurs with high
yield and in mild conditions. The same process has been successfully applied to the chemistry of aminoglycosides
producing a neomycin-hexafluorovaline-galactose conjugate and providing a general, efficient
strategy to functionalized aminoglycosides with sugar-hexafluorovaline tags
Multi-Component Sequential Synthesis of Dihydroorotic Acid-Based Amphiphilic Molecules
Get PDFAn efficient multicomponent sequential process, which occurs
in mild condition has been exploited for the synthesis of systematically
modified amphiphilic molecules where the cationic head is tethered
to a lipophilic tail through a dihydroorotic acid linker. The process
is operatively simple, high yielding, and flexible. Such a strategy could
impact combinatorial synthesis of wide libraries of amphiphilic molecules
to be tested as transfection agents and/or as antimicrobials
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
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
A simple method for the selective deprotection of p-methoxybenzyl ethers by cerium(III) chloride heptahydrate and sodium iodide
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InternaL Lewis acid coordination as a powerful tool to promote highly strereoselective alkylation of alfa-alkyl-beta-hydroxy ketones with Grignard Reagents
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