Synthesis characterization and biological evaluation of 1 2 4 oxadiazole quinoxaline and pyrano fused pyrazole derivatives

Abstract

Natural products and their analogs have contributed majorly to medical therapy, especially for various diseases like cancer and infectious diseases. However, natural products also carry challenges for drug discovery, such as technical barriers to screening, isolation, characterization, and optimization in the pharmaceutical industry. Thus, it is a common strategy to structurally modified the natural molecules to improve their medical therapy. A number of the natural products possess hetero atoms in their structure motifs, known as heterocyclic compounds, and are the key classes of organic chemistry. 1,2,4-oxadiazole, quinoxaline, and pyrano fused pyrazole are the heterocyclic compounds containing various heteroatoms oxygen, and nitrogen possess various biological activities. newlineThere are various isomers of oxadiazole exits out of which 1,2,4-oxadiazole, 1,2,5-oxadiazole, and 1,3,4-oxadiazole are having very good biological activities and appear in various pharmaceutical drugs eg. raltegravir, butalamine, fasiplon, oxolamine, and pleconaril. This 3,5-disubstituted 1,2,4-oxadiazole possesses prominent biological importance and there are various ways by which these substituted oxadiazoles derivatives are synthesized. newlineQuinoxaline is again a class of heterocyclic compounds and is formed by the fusion of benzene and pyrazine ring. The common procedure to prepare quinoxaline is the simple condensation of substituted o-phenylenediamine with and#945;-dicarbonyl compounds to afford diversely functionalized quinoxaline. The various quinoxaline derivatives containing triazolo, pyrazole, indolo, macrocycles, and benzoxazepine showed good biological properties. newlinePyrano fused pyrazole is one more class of heterocyclic compound and is formed by the two or multicomponent condensation of and#946;-ketoesters, hydrazine monohydrate/phenylhydrazine, malononitrile, and substituted benzaldehyde. This class of compounds is of great interest due to its vast biological importance like anti- cancer, anti-inflammatory, anti-microbial, analgesic, and enzyme