Quinoxaline: An insight into the recent pharmacological advances.

Synthesis and Biological Applications of Triazole Derivatives – A Review

Procedures and Theoretical Considerations forTtesting Antimicrobial Agents in agar media

Present status of quinoxaline motifs: Excellent pathfinders in therapeutic medicine

The importance of triazole scaffold in the development of anticonvulsant agents

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

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-1,3,4oxadiazol-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 quinoxalin2(1H)-ones 5a-c. Finally, the compounds 5a-c are converted to 3-methyl-7-substituted-1-{[5-(alkylsulfanyl)-1,3,4oxadiazol-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, 1 H NMR, 13 C 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.

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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

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-1,3,4oxadiazol-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 quinoxalin2(1H)-ones 5a-c. Finally, the compounds 5a-c are converted to 3-methyl-7-substituted-1-{[5-(alkylsulfanyl)-1,3,4oxadiazol-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, H NMR, C 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 2-(3-Methyl-7-substituted-2-oxoquinoxalinyl)-5-(aryl)-1,3,4-oxadiazoles as Potential Nonsteroidal Antiinflammatory and Analgesic Agents.

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, 1 H NMR, 13 C 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...

Synthesis of Some Novel 2,4-Disubstituted Thiazoles as Possible Antimicrobial Agents

Renewable resources and waste materials can be used as viable raw materials to prepare security formulations devoid of volatile organic compounds and would essentially offer environmental protection. Therefore, chitosan (deacetylated chitin), which is a marine waste material is modified through simultaneous N-conjugation with pyrene-1-carboxaldehyde (PCA) as an aggregation caused quenching fluorophore and fluorene-2-carboxaldehyde (FCA) to obtain a smart fluorescent chitosan-based Schiff base (FCSSB). The covalent attachment could immobilize pyrene onto the chitosan, and the subsequent diluting effect of the biopolymer framework could hinder the aggregation of pyrene and, thereby, the self-quenching of fluorescence. The modified FCSSB could serve as a multi-functional material; both as a binder and a fluorophore in an eco-friendly formulation using aqueous acetic acid as the mild solvent and glycerol as the viscosity regulator. The formulation is used as a security ink to obtain single/multilayer coating/s and further prints using flexography technique. The prints that appeared invisible in daylight exhibited a blue fluorescence under 370 nm UV illumination. Moreover, the ink film presented good rub resistance and colour stability after different cycles of UV exposure. Therefore, FCSSB formulation can be readily utilized as a security ink for information decryption and could also be processed into products of diverse forms, including ink pads, coatings, printed patterns, and films. This simple, but effective approach provides additional impetus to real-life applications of biopolymers from natural/waste materials in anti-counterfeiting. 

Shivananda Wagle

Papers

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

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

Synthesis of Some New 2-(3-Methyl-7-substituted-2-oxoquinoxalinyl)-5-(aryl)-1,3,4-oxadiazoles as Potential Nonsteroidal Antiinflammatory and Analgesic Agents.

Synthesis of Some Novel 2,4-Disubstituted Thiazoles as Possible Antimicrobial Agents

Modified chitosan as a multi-functional material in eco-friendly formulation for anti-counterfeit applications