18633-05-1Relevant academic research and scientific papers
Synthesis of aza derivatives of isomers of angular and complex phenothiazine rings
Ezema, Benjamin E.,Ezema, Chidimma G.,Ayogu, Jude I.,Ugwu, David I.,Onoabedje, Efeturi A.
, p. 379 - 385 (2015)
Isomeric derivatives of angular aza benzophenothiazine and complex aza benzothiazinophenothiazine rings were successfully synthesized. Reactions of 2-amino-3,5-dibromopyrazine with 6,7-dibromoquinoline-5,8-dione in anhydrous sodium carbonate gave isomeric angular aza benzophenothiazine compounds 6,9-dibromo-1,8,11-triazabenzo[a]phenothiazine-5-one and 6,9-dibromo-4,8,11-triazabenzo[a]phenothiazine-5-one. Further reactions of these compounds, in the first case, respectively with 2-amino-6-methoxypyridin-3-thiol gave the two isomeric aza complex compounds identified as 13-bromo-8-methoxy-1,9,12,15-tetraazabenzo[a][1,4]benzothiazino[3,2-c]phenothiazine and 13-bromo-8-methoxy-4,9,12,15-tetraazabenzo[a][1,4]benzothiazino[3,2-c]phenothiazine. Secondly, reactions of the same angular benzophenothiazine compounds with 4-aminopyrimidin-5-thiol gave two more complex compounds 13-bromo-1,6,8,12,15-pentaazabenzo[a][1,4]benzothiazino[3,2-c]phenothiazine and 13-bromo-4,6,8,12,15-tetraazabenzo[a][1,4]benzothiazino[3,2-c]phenothiazine. The compounds have very intense colours. Keywords: anhydrous sodium carbonate; 2-amino-3,5-dibromopyrazine; 2-amino-6-methoxypyridin-5-thiol; 4-aminopyrimidin-5-thiol; 6,7-dibromoquinoline-5,8-dione; condensation reaction.
Palladium catalyzed transformation and antimicrobial screening of novel angular azaphenothiazines
Godwin-Nwakwasi,Okoro,Ijeomah,Agbo,Ezeokonkwo
, p. 742 - 748 (2017/02/10)
Base mediated condensation reaction between 2-amino-5-bromopyrazine-3[4H]-thione and 7-chloro-5,8-quinolinequinone under anhydrous condition gave 9-bromo-1,8,11-triaza-5H-benzo[a]phenothiazin-5-one. Palladium catalyzed cross-coupling reaction between 9-bromo-1,8,11-triaza-5H-benzo[a]phenothiazin-5-one and four arylated halogeno compounds utilizing Heck-Mizoroki protocol furnished 6-substituted derivatives of the angular tetracyclic heterocycle. Structures were assigned based on spectroscopic and elemental analytical data. Antimicrobial screening of these compounds showed they were biologically active.
New Aryl Derivatives of Quinolinedione and Related Heterocyclic Compounds
Egu, Samuel Attah,Okoro, Uchechukwu Chris,Onoabedje, Efeturi Abraham
, p. 1572 - 1577 (2017/03/27)
The synthesis of new derivatives of 6,7-dibromoquinoline-5,8-dione and 6,7-dichloroquinoline-5,8-dione via palladium/Sphos-mediated Suzuki–Miyaura cross-coupling reaction is reported. The 6,7-dibromoquinoline-5,8-dione and 6,7-dichloroquinoline-5,8-dione intermediates were prepared in a three-step reaction from 8-hydroxyquinoline. The palladium-catalyzed reactions of 6,7-dibromoquinoline-5,8-dione and 6,7-dichloroquinoline-5,8-dione with a variety of aryl boronic acids provide coupled compounds in high yields. The arylation of 6,7-dibromoquinoline-5,8-dione and 6,7-dichloroquinoline-5,8-dione with 4-bromophenyl boronic acid supplied 6,6′-(1,4-phenylene)bis(7-bromoquinoline-5,8-dione) and (4-(6-(4-(6-chloro-5,8-dihydroquinolin-7-yl)phenyl)-5,8-dihydroquinolin-7-yl)phenyl)boronic acid respectively, in addition to the expected coupled compounds in moderate yields. Also, Pd(0)/PPh3 allowed the 7-chloro-6-(4-nitrophenyl)quinoline-5,8-dione and 7-chloro-6-phenylquinoline-5,8-dione to be synthesized via Heck reaction. The yields of the synthesized target molecules depend largely on the reaction conditions and the type of ligands employed. Structural assignments of the synthesized compounds were established by spectra and analytical data.
Antiviral agents. I. Synthesis and antiviral evaluation of trimeric naphthoquinone analogues of conocurvone
Crosby, Ian T.,Rose, Mark L.,Collis, Maree P.,De Bruyn, Paula J.,Keep, Philip L. C.,Robertson, Alan D.
, p. 768 - 784 (2008/12/22)
Conocurvone, a novel natural product isolated from the endemic Australian shrub Conosperum sp. (Proteaceae), exhibits anti-HIV activity but is a highly lipophilic compound, which suggests that there may be problems with its aqueous solubility and bioavailability. A general and convenient synthesis of trimeric naphthoquinones using the condensation of 2-hydroxynaphthoquinones and 2,3-dihaloquinones is described. The application of this method to the synthesis of a series of simpler and less lipophilic trimeric naphthoquinone simple analogues of conocurvone is also reported together with their anti-HIV activity. CSIRO 2008.
6,7-Disubstituted -5,8-quinolinedione derivatives as an antifungal agent
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Page column 5, (2008/06/13)
Novel 6,7-disubstituted-5,8-quinolinedione derivatives of general formula (I) or the process for the preparation thereof, wherein R1is C1-C20alkylmercapto or phenylamino substituted by up to 3 groups selected from halogen, aceto; R2is halogen, thiocyano or C1-C20alkylmercapto, are useful as an antifungal agent.
Inhibition of the arachidonic acid cascade by aza-2-aryl-1,4-naphthoquinone derivatives
Richwien,Wurm, Gotthard
, p. 906 - 912 (2007/10/03)
To find more potent 5-lipoxygenase(LO)-inhibitors than the up to now studied 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-3-hydroxy-1,4-naphthoquinone derivatives the analogous aza-1,4-naphthoquinones 14, 15, 16/17 as well as the 3-bromo precursors 7, 8, 9/10 and 11 were synthesized. The naphtho[2,1b][1,4] thiazin derivative 21 was included in this investigation as a quinone imine. Beside 5-LO inhibition the influence on 12-LO, COX-1 and cPLA2 was determined to investigate the selectivity of the compounds within the arachidonic acid cascade. To test the biochemical properties human granulocytes (5-LO) and human platelets (12-LO/COX-1 and cPLA2) were used. All 3-bromo compounds inhibit completely the arachidonic acid cascade by blocking the cPLA2. The 3-methoxy derivatives of the quinoline quinones 12 and 13 and the 3-hydroxyisoquinoline mixture 16/17 show 5-LO selectivity. 13 inhibits 5-LO selectively, 12 is a dual 5-LO/COX-1-inhibitor and 16/17 are dual 12-LO/COX-1-inhibitors. To verify the hypothesis that the hydroxylated 2-aryl-1,4-benzoquinone structure is the pharmacophore for 5-LO-inhibition within the class of 2-aryl-1,4-naphtho- and -aza-naphthoquinones the 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-1,4-benzoquinones 24-28 were synthesized. It was shown that the 5-methoxy and 5-hydroxy compounds 24 and 27 are highly selective and potent 5-LO-inhibitors.
New efficient syntheses of 6,7-dibromoquinoline-5,8-diones
Choi, Man Young,Lee, Byoung Se,Chi, Dae Yoon,Kim, Dong Jin
, p. 2647 - 2652 (2007/10/03)
Key intermediates for potential antitumor or antifungal agents, 2- and 3-methyl-6,7-dibromoquinoline-5,8-diones have been synthesized from 2,5-dimethoxyaniline and acrolein derivatives in three-step-one-pot with 38-41% isolation yields using Skraup reaction. The three steps are ring formation of quinoline, didemethylation, and oxidation of hydroquinone including dibromination on C6 and C7 positions.
