Synthesis of new 2-(5-substituted-3-phenyl-2-pyrazolinyl)-1,3-thiazolino[5,4-b]quinoxaline derivatives and evaluation of their antiamoebic activity

In an effort to develop potent antiamoebic agents, we have synthesized chalcones (1–8), amino-5-substituted-(3-phenyl(2-pyrazolinyl))methane-1-thione derivatives (1a–8a) and 2-(5-substituted-3-phenyl-2-pyrazolinyl)-1,3-thiazolino[5,4-b]quinoxaline derivatives (1b–8b) and evaluated for their in vitro antiamoebic activity against HM1:IMSS strain of E. histolytica. All the compounds were characterized by electronic, IR, 1H NMR and mass spectroscopic data. It was observed that the antiamoebic activity enhances on modifying the structure of chalcones to the pyrazolines and further to quinoxalines. The MTT assay was performed on human kidney epithelial cell line to check the cytotoxicity of the compounds and the results were compared with metronidazole. Compound 6b showed better antiamoebic activity and less toxicity than metronidazole.

Graphical abstract Some quinoxaline derivatives (1b–8b) were synthesized and evaluated for their in vitro antiamoebic activity against HM1:IMSS strain of E. histolytica. Compound 6b showed less toxicity with better antiamoebic activity than metronidazole.Figure optionsDownload full-size imageDownload as PowerPoint slide