1,720,983 research outputs found
[Quinolizidinyl derivatives of tricyclic systems]
No full textSince the pharmacological screening of several lupinyl- and lu lupinyldene derivatives of three-ring systems showed several interesting activities on the C.N.S., new investigations have been undertaken in order to understand the neurochemical mechanisms underlying such activities (influence on the uptake of choline, norepinephrine and serotonin by isolated rat brain synaptosomes). Thus the series of lupinyl derivatives has been completed with N-lupinyl-2-chloroiminodibenzyl and N-lupinyl-2,3-hexamethyleneindole; moreover, for all the three-ring systems so far considered, the corresponding epi-lupinyl- and epi-lupinylidenderivatives have been prepared in order to check the significance of the steric relationships between the quinolizidine ring and the tricyclic systems. The latter compounds differ from those formerly described for the equatorial position (rather than axial) of the methylene or methine group joining the quinolizidine nucleus to the three-ring systems
Preparation of quinolizidinyl derivatives of phenothiazine and thioxanthene of pharmacological interest
No full textQuinolizidinyl derivs. of phenothiazine and thioxanthene, e.g. I, were prepd. to study the effects on the uptake and release of some neurotransmitter in rat brain synaptosomes. In one attempt to prep. the homolupinanoylphenothiazine from homolupinanoyl chloride a compd. was obtained, to which the structure of 2,4-diquinolizidinylcyclobutan-1,3-dione (II) was assigned. When heated with acids this compd. gives rise to the dilupinyl ketone, also obtained from cyanolupinane and lupinylmagnesium chloride
Quinolizidine derivatives as potential antitumoral agents
No full textThe activity against lymphocytic leukemia P 388 has been evaluated for thirteen compounds bearing a quinolizidine moiety bound respectively to a phenothiazine nucleus or other isosteric tricyclic systems (12-17), as well to a quinoxalinone (18-20) or an indole (21-24) nucleus. All tested compounds resulted inactive
[Synthesis and pharmacologic activity of 3-quinolizidine-1'-yl-5-R-indoles]
No full textBy acid action on the mixture of homolupinal diethylacetal and arylhydrazines several 3-quinolizidin-1'-yl-5-R-indoles (III a - III e) were prepared. The homolupinal diethylacetal, whose hydrolysis gives rise to the unknown aldehyde, was obtained through the action of lupinylmagnesium chloride on diethylphenylorthoformate. Compounds (III) were subjected to wide pharmacological screening; all of them exhibited calcium blocking, negative cardioinotropic and diuretic activities, while single compounds showed antiinflammatory (III d), anticonvulsant and hypoglycemic (III e) activities
Epimerization of Lupinine to Epilupinine and viceversa. Reexamination of the Structures of Lupinal and Epilupinal
No full textAlthough the epimerization of lupinine (I) has been largely investigated, a previously not obsd. compd. of formula C10H17NO was now isolated from the mixt. of alkaloids that remains after the sepn. of epilupinine (II). It is insol. in dry Et2O but sol. in EtOH, from which it is recovered as an Et2O-sol. oil that slowly returns to the Et2O-insol. solid form. For these characteristics and based on GC/MS, 1H-NMR, and IR data, it is considered as the inner salt III of the common enolic form IV of lupinal and epilupinal, with which it is in equil. when standing in soln. The oily form, but not the solid one, is able to improve the conversion of I to II, establishing the role of the aldehydes in the epimerization process. It was obsd. that also II can be converted to I. Finally, the solid lupinal described by Zaboev should be considered as being identical to the now isolated inner salt III, while the oily epilupinal of Wicky and Schumann is, indeed, a mixt. of epilupinal with a minor amt. of lupinal, which, on standing, is converted to the inner salt III of the common enolic form IV
Poor interaction of some quinolizidine derivatives with dopamine D1- and D2- type receptors
No full textThe displacement of [3H]SCH-23390 and of [3H]spiperone from striatal, dopamine D1- and D2-type receptors by several quinolizidinyl-derivatives of bi- and tricyclic systems was investigated. All tested compounds did not affect SCH-23390 binding and exhibited only weak activity on spiperone binding to D2 binding sites (Ki = 1.9 microM). Therefore the good deconditioning activity (CAR blockade in rats) of 6-chloro-1-lupinyl-3-methyl-quinoxalinone (18) must rely on interactions with other kinds of receptors
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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