1,721,116 research outputs found
Boosting Catalyst Activity in Cis-Selective Semi-Reduction of Internal Alkynes by Tailoring the Assembly of All-Metal Aromatic Tri-Palladium Complexes Showcasing research from Prof. Maestri (UniPR) and Prof. Malacria (UPMC/CNRS)
No full textThrough the design of an optimised catalytic system for the semi-reduction of internal alkynes to cis-alkenes we showed that [Pd3]+ clusters with delocalized metal-metal bonds deliver desired products with complete selectivity and very low catalyst loadings (0.03 mol%)
Palladium- and Norbornene-Catalyzed Synthesis of Highly Functionalized Thiophenes: The Remarkable Effect of Electron-Poor Olefins as Ligand
No full textHighly functionalized heterocyclic compounds were synthesized by palladium and norbornene catalysis starting from ortho-substituted aryl iodides, aryl bromides and 3,4-ethylenedioxythiophene. The addition of methyl cinnamate to the reaction mixture was found to be crucial in order to obtain selectively the unsymmetrical produc
Method for preparing marmycin A and analogs thereof, and also uses thereof as antibiotics, anticancer, and antimalarials agents
No full textThe present invention relates to a process of prepn. of marmycine A and its analogs, new analogs of marmycine A, as well as the use as a marker of organoids and in pharmacy of these compds., in particular as antibiotics, anti-cancer and antipaludic. The present invention relates to a method for prepg. marmycin A and analogs I, wherein R1-R11 are independently an atom or group of atoms via copper-catalyzed coupling reaction of anthracene-9,16-diones with aminoglycosides; as an organelle marker and in pharmacy, in particular as antibiotics, anticancer, and antimalarial agents. Here, we report the chem. synthesis of marmycin A and the study of its cellular activity. The arom. core was constructed by means of a one-pot multistep reaction comprising a regioselective Diels-Alder cycloaddn., and the complex sugar backbone was introduced through a copper-catalyzed Ullmann cross-coupling, followed by a challenging Friedel-Crafts cyclization. Remarkably, fluorescence microscopy revealed that marmycin A does not target the nucleus but instead accumulates in lysosomes, thereby promoting cell death independently of genome targeting. Furthermore, a synthetic dimer of marmycin A and the lysosome-targeting agent artesunate exhibited a synergistic activity against the invasive MDA-MB-231 cancer cell line. These findings shed light on the elusive pathways through which anthraquinone derivs. act in cells, pointing towards unanticipated biol. and therapeutic applications
Pd-Catalyzed Sequential Reactions Involving C–H Bond Activation: A Green and Sustainable Tool for Natural and Industrial Product Synthesis
No full textThe following sections are included:
Introduction: Green Chemistry and Sustainability
Sequential Reactions
C–H Activation
Relevant Selected Examples
Conclusion
Reference
Catalytic Cycloaddition Reactions
No full textThis chapter covers recent developments in transition metal catalyzed cycloadditions involving alkynes. Late transition metals are the catalysts of choice for these cascades allowing a straightforward access to molecular complexity from acyclic precursors. This overview covers both mechanistic aspects and synthetic applications of this vast and fruitful domai
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
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