Syntheses and evaluation of 3-(3-bromo phenyl)-5-phenyl-1-(thiazolo [4,5-b] quinoxaline-2-yl)-2-pyrazoline derivatives

A variety of 3-(3-bromo phenyl)-5-phenyl-1-(thiazolo [4,5-b] quinoxaline-2-yl)-2-pyrazoline were obtained by the refluxing of 1-N-thiocarbamoyl 3,5-diphenyl-2-pyrazoline with 2,3-dichloroquinoxaline. The chemical structures of the compounds were elucidated by UV, IR, 1H NMR, and 13C NMR spectroscopy. The purity of the compounds was confirmed by their elemental analysis. The antiamoebic activity of these compounds was evaluated by microdilution method against HMI:IMSS strain of Entamoeba histolytica and the IC50 values were compared with the standard drug metronidazole. Some of the quinoxaline derivatives showed less IC50 values than metronidazole. To elucidate the toxic effect, MTT assay was performed using kidney epithelial cell line. The results showed that all the compounds are non-toxic.

Graphical abstractA variety of 3-(3-bromo phenyl)-5-phenyl-1-(thiazolo [4,5-b] quinoxaline-2-yl)-2-pyrazoline were obtained by the refluxing of 1-N-thiocarbamoyl 3,5-diphenyl-2-pyrazoline with 2,3-dichloroquinoxaline. The antiamoebic activity of these compounds was evaluated against Entamoeba histolytica. Some of the quinoxaline derivatives showed less IC50 values than metronidazole. To elucidate the toxic effect, MTT assay was performed using kidney epithelial cell line. The compound 18 has lowest toxicity and highest antiamoebic activity.Figure optionsDownload full-size imageDownload as PowerPoint slide