1,721,474 research outputs found
Synthesis of N,N'-dibenzylethylenediamine via palladium-carbon-catalysed reductive alkylation
No full textReductive alkylation of ethylenediamine with benzaldehyde and hydrogen in the presence of Pd-C has been investigated in order to optimize the synthesis of N,N'-dibenzylethylenediamine; the efficiency of the procedure has been improved by minimizing undesired competing reactions of cyclization and hydrogenolysis
2-Hydroxymethyl-1,4-dioxane: synthesis, resolution and determination of the absolute configurations of the enantiomers
No full text2-Hydroxymethyl-1, 4-dioxane 3 was resolved via salt formation between its hydrogen phthalate and (R)- or (S)-1-phenylethylamine, selective crystallization of the resultant diastereomeric mixtures and subsequent recovery of its enantiomers by saponification. The progress of the resolution was followed by chiral HPLC and the absolute stereochemistry of the two enantiomers determined by comparison of their specific rotations with that of (R)-3 synthesized from enantiomerically pure (R)-1-O-benzylglycerol. The results of the synthesis of 3 and of its resolution are discussed and compared with those previously obtained for 1,2-isopropylidene glycerol evaluating the consequences of replacement of ispropylidene with an ethylene bridge
Addressing Motor Dysfunction by a Selective α6-Containing Nicotinic Receptor Antagonist
Get PDFIn the striatum, presynaptic α6-containing nicotinic receptors are crucially involved in the modulation of dopamine release. CVN417, a novel selective antagonist at this receptor subtype, attenuates motor dysfunction in a Parkinson’s disease-relevant animal model, suggesting, for this pathology, a therapeutic strategy that could greatly profit from the restricted localization of α6* nicotinic receptors in the brain
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
SEARCH FOR SELECTIVE ANTAGONISTS AT α1-ADRENORECEPTOR SUBTYPES: WB-4101 RELATED COMPOUNDS
No full textThe development of subtype selective α1 ligands is intensively pursued in order to obtain more effective and safer agents for the treatment of cardiovascular pathologies such as hypertension and arrhythmia, but also and particularly of benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS).
One of the oldest and most potent α1 antagonists is represented by WB-4101, a 2-aminomethyl-1,4-benzodioxane derivative which is slightly selective for α1A and, to a minor extent, for α1D-ARs with respect to α1B-AR and 5-HT1A serotoninergic receptor. Many structural modifications of WB-4101 have been done to improve both affinity and selectivity.1-4 Some evidences, resulting from mutagenesis and docking studies, suggest that the benzodioxane moiety and the 2,6-dimethoxyphenoxy residue of WB-4101 are, respectively, involved in conferring α1a selectivity and high α1 affinity. Consistently with these findings, our recent researches have demonstrated that removal of one or both ortho-methoxy substituents adversely affects the affinity for the three α1-AR subtypes, but not that for the 5-HT1A receptor.3
On the basis of these indications, we synthesized a number of S and R analogues of WB-4101, characterized by different substitutions at the benzodioxane and/or phenoxy fragment, in order to modulate and, hopefully, to improve the activity and selectivity profile of the parent compound. In particular, we considered derivatives with benzodioxane 8-substituted with F,4 Cl, OH or OMe 4 or fused with a cyclohexane to give a tetrahydronaphthodioxane polycycle.2 On the other hand, 2,6-dimethoxyphenyl residue was replaced by ortho methoxy substituted 1-naphthyl 2 or biphenyl systems. Finally, hybrid structures were designed combining some of the above modifications. After binding assays, which demonstrated the better α1a, α1b, α1d and 5-HT1A affinity of the S enantiomers, these latter were tested in functional assays on isolated tissues, finding that almost all were able to discriminate among the α1-AR subtypes.
1. Bolognesi M.L., Budriesi R., Cavalli A., Chiarini A., Gotti R., Leonardi A., Minarini A., Poggesi E., Recanatini M., Rosini M., Tumiatti V., Melchiorre C. J.Med.Chem. 1999, 42, 4214-4224.
2. Bolchi C., Catalano P., Fumagalli L., Gobbi M., Pallavicini M., Pedretti A., Villa L., Vistoli G., Valoti E. Bioorg.Med.Chem. 2004, 12, 4937-51.
3. Fumagalli L., Bolchi C., Colleoni S., Gobbi M., Moroni B., Pallavicini M., Pedretti A., Villa L., Vistoli G., Valoti E. Bioorg.Med.Chem. 2005, 13, 2547-2559.
4. Valoti E., Pallavicini M., Villa L., Pezzetta D. J.Org.Chem. 2001, 66, 1018-1025
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
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