1,721,058 research outputs found
Synthesis of 1,2,4,-Triazolo[4',3':1,6]pyridazino[4,5-b]quinoline Derivatives
No full textThis paper reports the synthesis of 10‐phenyl‐2H‐pyridazino[4,5‐b]quinoline‐1‐thione 10 and its further transformation into the hitherto unknown 12‐phenyl‐1,2,4‐triazolo[4′,3′:1,6]pyridazino[4,5‐b]quinoline 4. 3‐Carbethoxy‐2‐dichloromethyl‐4‐phenylquinoline 8 was reacted with hydrazine to give 9 which in turn was transformed by the Lawesson Reagent into the corresponding thione 10. On treating 10 with anhydrous hydrazine, 11 was obtained and subsequently cyclized in the presence of formic or acetic acids to afford the tetracyclic derivatives 4a and 4b, respectively, in satisfactory yields. When 3‐carbethoxy‐2‐chloromethyl‐4‐phenylquinoline 5 was reacted with hydrazine, compound 7 was the sole isolated product. Copyright © 1990 Journal of Heterocyclic Chemistr
Synthesis of Functionalized Derivatives of Quinazolines and 1,4-Benzodiazepines
No full textThe 2-substituted 1,4-benzodiazepines (4 and 6) were synthesized. The reaction of 2-aminobenzophenone oximes with ethyl 4-chloroacetoacetate gave the 1,4-benzodiazepines (4) and the 1,2-dihydroquinazolines (5); the latter were treated with a base to result ring expansion giving the 1,4-benzodiazepines (6)
L,5-DIARYL-2-ALKVLPVRROLE-3-SUBSTITUTED NITRO ESTERS, SELECTIVE COX-2 INHIBITORS AND NITRIC OXIDE DONORS
No full textThe present invention relates to l,5-diaryl-2-alkylpyrrole-3-substituted nitro esters, of formula (I), which are potent and selective COX-2 inhibitors able to release NO in concentrations that make it possible to counteract the side effects due to selective COX-2 inhibition, without giving rise to hypotensive effects. (I). Where the groups R' and R" are: -H, -F, -CI, -Br, -CH3, -CF3, -OCH3, -SCH3, R1 is methyl, ethyl, trifluoromethyl, hydroxymethyl, methoxymethyl and the substituent in position -3 of the pyrrole ring is a chain, where the groups X, Y, Z, W and R2 are: X is a carbonyl or a group -(CHR3)-, Y is an oxygen atom or the group -NR3- and Z is a carbonyl or a group - (CHR3)-, or a [-CH(COOH)-] group, or a group -(NR3)-, W is an aliphatic chain substituted with one or two (-O-NO2) groups, R2 is: -H, -OH, -OCH3, or -NHR3. R3 is: -H, -CH3, -CH2CH3, [-CH2(CH3)2]. R'" is methylsulphonyl or sulphonamido. The purpose of the invention includes: preparation of the compounds of formula (I), the respective pharmaceutical formulations and use thereof for treating acute and chronic pain, for treating inflammatory disorders and for drug treatment of some forms of tumours
Polycondensed heterocycles. VII. A convenient synthesis of pyrrolo[1,2-a]quinoxaline derivatives by intramolecular aromatic nucleophilic displacement
No full text4-(4-Methyl-1-piperazinyl)-7-trifluoromethylpyrrolo[1,2-a]quinoxaline (CGS 12066B) and related analogs were prepared in good overall yield through a reaction sequence involving as a key step the intramolecular substitution of aromatic fluoride or nitro groups by a carboxamide moiety. © 1991, Taylor & Francis Group, LLC. All rights reserved
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
Polycondensed heterocycles. III. Synthesis of 5,11-dioxo-1,2,3,11a-tetrahydro-5H,11H- and 5-oxo-2,3,11,11a-tetrahydro-1H,5H-pyrrolo[2,1-c][1,4]benzothiazepine
No full textThe syntheses of 5,11‐dioxo‐1,2,3,11a‐tetrahydro‐5H11H‐ and 5‐oxo‐2,3,11,11a‐tetrahydro‐1H,5H‐pyrrolo‐[2,1‐c][1,4]benzothiazepine 10 and 11 have been studied. The former was obtained by intramolecular cyclization with CDI of N‐(2‐mercaptobenzoyl)‐L‐proline 19, prepared on one hand by demethylation of N‐(2‐methylthiobenzoyl)‐L‐proline t‐butyl ester 15, obtained via the Pummerer rearrangement of the corresponding sulphoxide 17 and successive alkaline hydrolysis, and by deprotection of the mercapto ester 18 with TFA or trimethylsilyl iodide. The ester 15 was achieved by reaction of o‐(methylthio)benzoic acid 12 with L‐proline t‐butyl ester or by treatment of the corresponding acid chloride 13 with L‐proline and successive esterification of N‐(2‐methylthiobenzoyl)‐L‐proline 16. On the other hand the proline 19 was also obtained by reduction with sodium dithionite of (S)‐bis[2‐[[2‐(hydroxycarbonyl)‐1‐pyrrolidinyl]carbonyl]phenyl] disulphide 20, prepared by condensation of bis(2‐chlorocarbonylphenyl) disulphide 14 with L‐proline. The reduction of (S)‐bis[2‐[[2‐(chloromethyl)‐1‐pyrrolidinyl]carbonyl]phenyl] disulphide 28 with sodium borohydride in boiling ethanol afforded directly the benzothiazepinone 11 in 85% yield. The disulphide 28 was synthesized treating the corresponding alcohol 24 or N‐(2‐mercaptoben‐zoyl)‐L‐prolinol 25 with thionyl chloride. Compound 25 was obtained by demethylation of the corresponding methylthio ether 26 oxidized to sulphoxide 27 via the Pummerer rearrangement. The acid chloride 14 by condensation with (S)‐2‐(chloromethyl)pyrrolidine hydrochloride gave disulphide 28 as well. The acid chlorides 13 and 14 by reaction with L‐prolinol provided respectively alcohols 26 and 24. Attempts to cyclodehydrate the mercapto alcohol 25, obtained also by reduction of disulphide 24, failed. Copyright © 1988 Journal of Heterocyclic Chemistr
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