Browsing by Author "Suchetha Kumari, N.S."

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Antimicrobial and antiinflammatory studies on some 1,2,4-triazolo[3,4-b][1, 3,4]thiadiazines and 1,2,4-triazolo[3,4-b][1,3,4]thiadiazoles containing quinoxaline
(Chemical Publishing Co., 2008) Wagle, S.; Vasudeva Adhikari, A.V.; Suchetha Kumari, N.S.
The reaction of 2-(3-methyl-2-oxo quinoxalin-1(2H)-yl) acetohydrazide (1), with carbon disulphide in presence of methanolic potassium hydroxide at 0°C affords potassium dithiocarbazate (2), which on treatment with 70 % hydrazine hydrate at 100°C undergoes smooth cyclization to give 1-[(4-amino-5- mercapto-4H-1,2,4-triazol-3-yl)methyl]-3-methyl quinoxalin-2(1H)-one (3), in good yield. This triazole has been conveniently converted into title compounds, 3-methyl-1-[(6-phenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl) methyl]quinoxalin-2(1H)-one (4a-j), by condensing it with phenacyl bromides in ethanol at reflux temperature. In another reaction, the triazole 3 has been treated with aromatic carboxylic acids in presence of phosphorus oxychloride at 100°C to afford title compounds, 3-methyl-1-[(6-phenyl[1,2,4]triazolo[3,4-b] [1,3,4]thiadiazol-3-yl)-methyl]quinoxalin-2(1H)-one (5a-j). The prepared compounds have been characterized by IR, 1H NMR, 13C NMR and mass spectral data, followed by elemental analysis. These compounds were screened for their in vitro antibacterial activity against five pathogenic strains and antifungal activity against four fungi. Further, selected compounds were subjected to in vivo antiinflammatory activity. Few of them exhibited promising activity.
Synthesis of some new 2-(3-methyl-7-substituted-2-oxoquinoxalinyl)-5-(aryl) -1,3,4-oxadiazoles as potential non-steroidal anti-inflammatory and analgesic agents
(2008) Wagle, S.; Vasudeva Adhikari, A.V.; Suchetha Kumari, N.S.
Ethyl (3-methyl-7-substituted-2-oxoquinoxalin-1(2H)-yl) acetates 2a-c are prepared by the condensation of ethyl chloroacetate with 3-methyl-7-substituted quinoxalin-2(1H)-ones 1a-c. The reaction of 2a-c with hydrazine hydrate furnished 2-(3-methyl-7-substituted-2-oxoquinoxalin-1(2H)-yl) acetohydrazides 3a-c, which on cyclisation with substituted aromatic carboxylic acids in the presence of phosphorous oxychloride give 3-methyl-7-substituted-1-[(5-aryl-1,3, 4-oxadiazol-2-yl)methyl]quinoxalin-2(1H)-ones 4a-y. Further, the compounds 3a-c on cyclisation with carbon disulphide in methanolic potassium hydroxide yielded 1-[(5-mercapto-1,3,4-oxadiazol-2-yl)methyl]-3-methyl-7-substituted quinoxalin-2(1H)-ones 5a-c. Finally, the compounds 5a-c are converted to 3-methyl-7-substituted-1-{[5-(alkylsulfanyl)-1,3,4-oxadiazol-2-yl]methyl} quinoxalin-2(1H)-ones 6a-i by reacting them with different alkyl halides. The newly synthesized compounds have been characterized by IR, 1H NMR, 13C NMR and mass spectral data and elemental analysis. Selected compounds are screened for in vivo anti-inflammatory and analgesic activity. Few of them exhibited promising activity.
Synthesis of some new 4-styryltetrazolo[1,5-a]quinoxaline and 1-substituted-4-styryl[1,2,4]triazolo[4,3-a]quinoxaline derivatives as potent anticonvulsants
(2009) Wagle, S.; Vasudeva Adhikari, A.V.; Suchetha Kumari, N.S.
4-Methyltetrazolo[1,5-a]quinoxaline (3) was prepared by the azide cyclocondensation of 2-chloro-3-methylquinoxaline (2). The reaction of 3 with aromatic aldehydes furnished 4-styryltetrazolo[1,5-a]quinoxalines (4a-f). Compound 2, on treatment with hydrazine hydrate gave 2-hydrazino-3-methylquinoxaline (5). The ring closure of 5 was achieved by the reaction of orthoesters and trifluoroacetic acid to yield 4-methyl-1-(substituted)[1,2,4]triazolo[4,3-a]quinoxalines (7a-c). Further, reaction of 7a-c with different aromatic aldehydes furnished the title compounds, 4-styryl-1-(substituted)[1,2,4]triazolo[4,3-a]quinoxalines (8a-i) in good yield. In another scheme, the hydrazino compound 5 was treated with different aromatic aldehydes to yield corresponding N-arylidenehydrazino quinoxalines (6a-d). Further, the oxidative cyclization of hydrazones by nitrobenzene yielded 1-aryl-4-methyl[1,2,4]triazolo[4,3-a]quinoxalines (7d-g), which on condensation with aromatic aldehydes gave the title compounds, 1-aryl-4-styryl[1,2,4]triazolo[4,3-a]quinoxalines (8j-u). The newly synthesized compounds have been characterized by FTIR, 1H NMR, 13C NMR and mass spectral data, followed by elemental analysis. Some of the compounds were screened for in vivo anticonvulsant activity. Few of them exhibited promising results. © 2008 Elsevier Masson SAS. All rights reserved.
Synthesis of some novel 2,4-disubstituted thiazoles as possible antimicrobial agents
(2008) Wagle, S.; Vasudeva Adhikari, A.V.; Suchetha Kumari, N.S.
A series of 4-aryl-2-(3-methyl-7-substituted quinoxaline-2-one-1-yl)-1,3- thiazoles (6a-l) and 4-substituted alkyl-2-(3-methyl-7-substituted quinoxaline-2-one-1-yl)-1,3-thiazoles (8a-i) were synthesized in good yield by condensing 2-(3-methyl-7-substituted l,2-oxoquinoxalin-1(2H)-yl)ethanethioamides (5a-c) with substituted phenacyl bromide and dichloroacetone followed by treatment with secondary amines, respectively. The intermediates, 5a-c were conveniently obtained by reacting phosphorus pentasulphide with 2-(3-methyl-7-substituted-2-oxoquinoxalin-1(2H)-yl) acetamides (4a-c) which in turn were synthesized from ethyl (3-methyl-7-substituted-2-oxoquinoxalin-1(2H)- yl) acetates (3a-c) by aqueous ammonia treatment. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR, and Mass spectral and elemental analyses. These compounds were screened for in vitro antibacterial activity against five pathogenic strains and antifungal activity against four fungi. Preliminary results revealed that some of the synthesized compounds showed promising antimicrobial activity. Copyright © Taylor & Francis Group, LLC.